To identify coatings and analyze the anti-detection capabilities of camouflage patterns, material samples can be prepared using the super-pixel segmentation method. A spectral polarization imaging system is developed,...To identify coatings and analyze the anti-detection capabilities of camouflage patterns, material samples can be prepared using the super-pixel segmentation method. A spectral polarization imaging system is developed, based on the principle of bidirectional reflectance distribution function(BRDF), to obtain spectral reflection intensities of coatings at full spatial angles, and use polarization images to calculate the refractive index by the Fresnel equation. The index is then coupled into TorranceSparrow model to simulate the spectral scattering intensity to mutually verify the experimental results. The spectral scattering characteristics of standard camouflage patterns are then revealed and pinpoint the signature band and the angle of reflecting sensitivity.展开更多
For conventional optical polarization imaging of underwater target,the polarization degree of backscatter should be pre-measured by averaging the pixel intensities in the no target region of the polarization images,an...For conventional optical polarization imaging of underwater target,the polarization degree of backscatter should be pre-measured by averaging the pixel intensities in the no target region of the polarization images,and the polarization property of the target is assumed to be completely depolarized.When the scattering background is unseen in the field of view or the target is polarized,conventional method is helpless in detecting the target.An improvement is to use lots of co-polarization and cross polarization detection components.We propose a polarization subtraction method to estimate depolarization property of the scattering noise and target signal.And experiment in a quartz cuvette container is performed to demonstrate the effectiveness of the proposed method.The results show that the proposed method can work without scattering background reference,and further recover the target along with smooth surface for polarization preserving response.This study promotes the development of optical polarization imaging systems in underwater environments.展开更多
Ovarian cancer is one of the most aggressive and heterogeneous female tumors in the world,and serous ovarian cancer(SOC)is of particular concern for being the leading cause of ovarian cancer death.Due to its clinical ...Ovarian cancer is one of the most aggressive and heterogeneous female tumors in the world,and serous ovarian cancer(SOC)is of particular concern for being the leading cause of ovarian cancer death.Due to its clinical and biological complexities,ovarian cancer is still considered one of the most di±cult tumors to diagnose and manage.In this study,three datasets were assembled,including 30 cases of serous cystadenoma(SCA),30 cases of serous borderline tumor(SBT),and 45 cases of serous adenocarcinoma(SAC).Mueller matrix microscopy is used to obtain the polarimetry basis parameters(PBPs)of each case,combined with a machine learning(ML)model to derive the polarimetry feature parameters(PFPs)for distinguishing serous ovarian tumor(SOT).The correlation between the mean values of PBPs and the clinicopathological features of serous ovarian cancer was analyzed.The accuracies of PFPs obtained from three types of SOT for identifying dichotomous groups(SCA versus SAC,SCA versus SBT,and SBT versus SAC)were 0.91,0.92,and 0.8,respectively.The accuracy of PFP for identifying triadic groups(SCA versus SBT versus SAC)was 0.75.Correlation analysis between PBPs and the clinicopathological features of SOC was performed.There were correlations between some PBPs(δ,β,q_(L),E_(2),rqcross,P_(2),P_(3),P_(4),and P_(5))and clinicopathological features,including the International Federation of Gynecology and Obstetrics(FIGO)stage,pathological grading,preoperative ascites,malignant ascites,and peritoneal implantation.The research showed that PFPs extracted from polarization images have potential applications in quantitatively differentiating the SOTs.These polarimetry basis parameters related to the clinicopathological features of SOC can be used as prognostic factors.展开更多
Optical clearing improves the penetration depth of optical measurements in turbid tissues.Polarization imaging has been demonstrated as a potentially promising tool for detecting cancers in superficial tissues,but its...Optical clearing improves the penetration depth of optical measurements in turbid tissues.Polarization imaging has been demonstrated as a potentially promising tool for detecting cancers in superficial tissues,but its limited depth of detection is a major obstacle to the effective application in clinical diagnosis.In the present paper,detection depths of two polarization imaging methods,i.e.,rotating linear polarization imaging(RLPI)and degree of polarization imaging(DOPI),are examined quantitatively using both experiments and Monte Carlo simulations.The results show that the contrast curves of RLPI and DOPI are different.The characteristic depth of DOPI scales with transport mean free path length,and that of RLPI increases slightly with g.Both characteristic depths of RLPI and DOPI are on the order of transport mean free path length and the former is almost twice as large as the latter.It is expected that they should have different response to optical clearing process in tissues.展开更多
The contrast mechanism of different polarization imaging techniques for melanoma in mouse skin is st udied using both experiments and Monte Carlo simulations.Total intensity,linear polariz-ation diference imaging(DPI)...The contrast mechanism of different polarization imaging techniques for melanoma in mouse skin is st udied using both experiments and Monte Carlo simulations.Total intensity,linear polariz-ation diference imaging(DPI),degree of polarization imaging(DOPI)and'rotating linearpolarization imaging(RLPl)are applied and the relative contrasts of these polarization imagingmethods between the normal and cancerous tissues are compared.A two-layer absorption-scat-tering model is proposed to explain the contrast mechanism of the polarization imaging formelanoma.By taking into account of both scattering of symmetrical and asymmetrical scat terersand absorption of inter-scatterer medium,the two-layer model reproduces the relative con trastsfor polarization images observed in experiments.The simulation results also show that,theparameters of polarization imaging change more dramatically with the variation of absorption inthe bottom layer than the top layer.展开更多
We apply diferent polarization imaging techniques for cancerous liver tissues,and compare the relative contrasts for difference polarization imaging(DPI),degree of polarization imaging(DOPI)and rotating linear polariz...We apply diferent polarization imaging techniques for cancerous liver tissues,and compare the relative contrasts for difference polarization imaging(DPI),degree of polarization imaging(DOPI)and rotating linear polarization imaging(RLPI).Experimental results show that a number of polarization imaging parameters are capable of differentiating cancerous cells in isotropic liver tisues.To analyze the contrast mechanism of the cancer:-sensitive polarization imaging parameters,we propose a scattering model cont aining two types of spherical scatterers and carry on Monte Carlo simula tions based on this bi-component model.Both the experimental and Monte Carlo simulated results show that the RLPI technique can provide a good imaging contrast of cancerous tissues.The bi-component scattering model provides a useful tool to ana-lyze the contrast mechanism of polarization imaging of cancerous tissues.展开更多
Differential polarization imaging has been widely used to selectively probe the target embedded in turbid medium.A thorough understanding of image quality involved in differential polarization imaging is essential for...Differential polarization imaging has been widely used to selectively probe the target embedded in turbid medium.A thorough understanding of image quality involved in differential polarization imaging is essential for practical use.Using polarized light Monte Carlo simulations,it has been investigated how the state of polarization of incident light and the optical properties of scattering medium affect the image contrast.The contrast for linear polarization is similar to that for circular polarization in the isotropic medium comprising small-particles.The image quality is more pronounced for circular polarization in the isotropic medium containing large-particles and the birefringent medium.Furthermore,differential polarization imaging provides better image quality for the birefringent medium compared with isotropic medium.The effect of particle-size and birefringence on the polarization characteristics of target light and backscattered light is investigated.With the help of numerical results,the polarization characteristics of target light and backscattered light,the image quality is well explained in the turbid medium mentioned above.展开更多
Recently,infrared polarization imaging technology has become a research hotspot due to its ability to better resolve the physicochemical properties of objects and significantly enhance the target characteristics.Howev...Recently,infrared polarization imaging technology has become a research hotspot due to its ability to better resolve the physicochemical properties of objects and significantly enhance the target characteristics.However,the traditional infrared polarization imaging is limited to similar imaging mechanism restrictions,and it is difficult to acquire the polarization information of a wide-area posture in real time.Therefore,we report a combination of hardware and software for super-wide-field-of-view long-wave infrared gaze polarization imaging technology.Utilizing the non-similar imaging theory and adopting the inter-lens coupling holographic linegrid infrared polarization device scheme,we designed the infrared gazing polarized lens with a field-of-view of over 160°.Based on the fusion of infrared intensity images and infrared polarization images,a multi-strategy detail feature extraction and fusion network is constructed.Super-wide-field-of-view(150°×120°),large face array(1040×830),detail-rich infrared fusion images are acquired during the test.We have accomplished the tasks of vehicle target detection and infrared camouflage target recognition efficiently using the fusion images,and verified the superiority of recognizing far-field targets.Our implementation should enable and empower applications in machine vision,intelligent driving,and target detection under complex environments.展开更多
Extended depth-of-field(DoF)imaging enhances longitudinal clarity but traditionally fails to record polarization information.Here,we propose a liquid-crystal Pancharatnam-Berry(PB)phase element that extends DoF while ...Extended depth-of-field(DoF)imaging enhances longitudinal clarity but traditionally fails to record polarization information.Here,we propose a liquid-crystal Pancharatnam-Berry(PB)phase element that extends DoF while sensing polarization ellipticity.Leveraging cubic-phase-induced defocus-insensitive point spread functions,a 10 cm DoF is achieved in a 10-cm-focal-length 4f system.Linear PB phases enable spin-orbit interactions to detect polarization states,overcoming irreversible polarization loss in conventional methods.This dual-functionality system integrates DoF extension with polarization sensing,enhancing multidimensional imaging capabilities and holding promise for advancing machine vision,microscopic imaging,and optical detection by merging depth clarity with polarization-based object differentiation.展开更多
Asan emerging poserful tool to provide structural informstion af tissue specimens label-freely,Mueller matrix(MM)polarimetry has garnered extensive attention in biomedical studies and pathological diagnois.However,for...Asan emerging poserful tool to provide structural informstion af tissue specimens label-freely,Mueller matrix(MM)polarimetry has garnered extensive attention in biomedical studies and pathological diagnois.However,for the commonly used constant-step rotating MM polarimetricsystem,beam drift induæd by the rotation of polarization eements can lead to distortions in messurement results,severely affect ing MM imaging accuracy.Here,based on our previous study,we prоровe an optimizad self-registration method to mitigate the psæudo-depolarization effects introduced by image artifacts in constant-step rotatin g MM polarimetry.By addresing the prevalent issue of beam drift and image distortions in such polarimetric imaging systems,the effectivenes of the proposed method is experimentally validated using tissue samples.The result.s demonstrate a significant enhanæment in the accuIrsсy of depolarization parameter estimation after applying the optimized self-registration method.Furthermore,the method enhances the coarseness and contrsst of MM-derived parameters images,thereby bolstering their capacity to characterize tissuestructures.The optimized self-registration method proposed in this study can provide an innovstive spproach for quantitative tissue polarimetry bssæd on constant-step ro tating MM messurement,and contribute to the advanæment of polarimetric imaging technology in biomedical applications.展开更多
The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact...The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact, quantification, rapidity, and high sensitivity, is expected to be used for auxiliary diagnosis of colorectal cancer. Herein, the differences in colorectal tissues of four pathological types were studied using this powerful technology. Polarized light imaging combined with the Mueller matrix decomposition (MMPD) method was applied to extract structural features that may be related to colorectal tumors. It demonstrated that parameters δ and θ could reflect the structural differences of colorectal tumors. Preliminary simulated experiment results revealed that the parameter δ was related to the fiber density, and the parameter θ was related to the fiber angle. Then Tamura image texture analysis was used to quantitatively describe tissues of different pathological types, and the results showed that the coarseness, contrast, directionality, and roughness of the four groups were statistically different. Texture analysis based on the quantitative data of the four dimensions could be applied for the identification of benign and malignant colorectal tumors.展开更多
In view of the problem that current mainstream fusion method of infrared polarization image—Multiscale Geometry Analysis method only focuses on a certain characteristic to image representation.And spatial domain fusi...In view of the problem that current mainstream fusion method of infrared polarization image—Multiscale Geometry Analysis method only focuses on a certain characteristic to image representation.And spatial domain fusion method,Principal Component Analysis(PCA)method has the shortcoming of losing small target,this paper presents a new fusion method of infrared polarization images based on combination of Nonsubsampled Shearlet Transformation(NSST)and improved PCA.This method can make full use of the effectiveness to image details expressed by NSST and the characteristics that PCA can highlight the main features of images.The combination of the two methods can integrate the complementary features of themselves to retain features of targets and image details fully.Firstly,intensity and polarization images are decomposed into low frequency and high frequency components with different directions by NSST.Secondly,the low frequency components are fused with improved PCA,while the high frequency components are fused by joint decision making rule with local energy and local variance.Finally,the fused image is reconstructed with the inverse NSST to obtain the final fused image of infrared polarization.The experiment results show that the method proposed has higher advantages than other methods in terms of detail preservation and visual effect.展开更多
Multispectral and polarized focusing and imaging are key functions that are vitally important for a broad range of optical applications.Conventional techniques generally require multiple shots to unveil desired optica...Multispectral and polarized focusing and imaging are key functions that are vitally important for a broad range of optical applications.Conventional techniques generally require multiple shots to unveil desired optical information and are implemented via bulky multi-pass systems or mechanically moving parts that are difficult to integrate into compact and integrated optical systems.Here,a design of ultra-compact transversely dispersive metalens capable of both spectrum and polarization ellipticity recognition and reconstruction in just a single shot is demonstrated with both coherent and incoherent light.Our design is well suited for integrated and high-speed optical information analysis and can significantly reduce the size and weight of conventional devices while simplifying the process of collecting optical information,thereby promising for various applications,including machine vision,minimized spectrometers,material characterization,remote sensing,and other areas which require comprehensive optical analysis.展开更多
Based on the characteristics that human eyes are sensitive to brightness and color, the lightness information of visible image and degree of linear polarization and polarization angle were fused in hue-saturation- va...Based on the characteristics that human eyes are sensitive to brightness and color, the lightness information of visible image and degree of linear polarization and polarization angle were fused in hue-saturation- value（HSV） space. To meet the observation of human eyes, hue adjustment based on color transfer was carried out to the fused image and hue was adjusted by polynomial fitting method. Hue adjustment method was improved considering the complicated real mapping relationship between hue gray scale of fused image and reference template image. The result shows that the color fusion method presented in this paper is superior to the traditional pseudo-color method and it is helpful to recognize the target from the environment correctly. The fusion result can reflect the difference of object＇s polarization characteristic, and get a natural fused image effect.展开更多
Mueller matrix imaging is emerging for the quantitative characterization of pathological microstructures and is especially sensitive to fibrous structures.Liver fibrosis is a characteristic of many types of chronic li...Mueller matrix imaging is emerging for the quantitative characterization of pathological microstructures and is especially sensitive to fibrous structures.Liver fibrosis is a characteristic of many types of chronic liver diseases.The clinical diagnosis of liver fibrosis requires time-consuming multiple staining processes that specifically target on fibrous structures.The staining proficiency of technicians and the subjective visualization of pathologists may bring inconsistency to clinical diagnosis.Mueller matrix imaging can reduce the multiple staining processes and provide quantitative diagnostic indicators to characterize liver fibrosis tissues.In this study,a fibersensitive polarization feature parameter(PFP)was derived through the forward sequential feature selection(SFS)and linear discriminant analysis(LDA)to target on the identification of fibrous structures.Then,the Pearson correlation coeffcients and the statistical T-tests between the fiber-sensitive PFP image textures and the liver fibrosis tissues were calculated.The results show the gray level run length matrix(GLRLM)-based run entropy that measures the heterogeneity of the PFP image was most correlated to the changes of liver fibrosis tissues at four stages with a Pearson correlation of 0.6919.The results also indicate the highest Pearson correlation of 0.9996 was achieved through the linear regression predictions of the combination of the PFP image textures.This study demonstrates the potential of deriving a fiber-sensitive PFP to reduce the multiple staining process and provide textures-based quantitative diagnostic indicators for the staging of liver fibrosis.展开更多
Recently,Mueller matrix(MM)polarimetric imaging-assisted pathology detection methods are showing great potential in clinical diagnosis.However,since our human eyes cannot observe polarized light directly,it raises a n...Recently,Mueller matrix(MM)polarimetric imaging-assisted pathology detection methods are showing great potential in clinical diagnosis.However,since our human eyes cannot observe polarized light directly,it raises a notable challenge for interpreting the measurement results by pathologists who have limited familiarity with polarization images.One feasible approach is to combine MM polarimetric imaging with virtual staining techniques to generate standardized stained images,inheriting the advantages of information-abundant MM polarimetric imaging.In this study,we develop a model using unpaired MM polarimetric images and bright-field images for generating standard hematoxylin and eosin(H&E)stained tissue images.Compared with the existing polarization virtual staining techniques primarily based on the model training with paired images,the proposed Cycle-Consistent Generative Adversarial Networks(CycleGAN)-based model simplifies data acquisition and data preprocessing to a great extent.The outcomes demonstrate the feasibility of training CycleGAN with unpaired polarization images and their corresponding bright-field images as a viable approach,which provides an intuitive manner for pathologists for future polarization-assisted digital pathology.展开更多
Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present ...Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present polarimeters usually perform a series of intensity measurements to carry out the polarization detection,making the process bulky and time-consuming.Thereby,compact and broadband-available polarimetry within a single snapshot is urgently demanded.We propose an all-liquid-crystal polarimeter for broadband polarization detection.It is cascaded by a q-plate and a polarization grating.The former is electrically tuned to meet the half-wave condition,whereas the latter is driven to deviate from this condition.After a polarized light passes through this device followed by a polarizer,its amplitude contrast and phase difference between orthogonal spins are read directly from the diffraction pattern.The intensity contrast between±1st orders depicts the amplitude contrast,whereas the rotating angle of the dark split reveals the phase difference.The Stokes parameters can be calculated accordingly.The polarimeter works in a broad spectral range of 470 to 1100 nm.Through presetting a q-plate array,polarization imaging is demonstrated.It supplies an all-liquid-crystal and full-visible-band tunable Stokes polarimeter that significantly promotes advances in polarization optics.展开更多
Non-line-of-sight[NLOS]imaging enables the detection and reconstruction of hidden objects around corners,offering promising applications in autonomous driving,remote sensing,and medical diagnosis.However,existing stea...Non-line-of-sight[NLOS]imaging enables the detection and reconstruction of hidden objects around corners,offering promising applications in autonomous driving,remote sensing,and medical diagnosis.However,existing steady-state NLOS imaging methods face challenges in achieving high efficiency and precision due to the need for multiple diffuse reflections and incomplete Fourier amplitude sampling.This study proposes,to our knowledge,a novel steady-state NLOS imaging technique via polarization differential correlography[PDC-NLOS].By employing the polarization difference of the laser speckle,the method designs a single-shot polarized speckle illumination strategy.The fast and stable real-time encoding for hidden objects ensures stable imaging quality of the PDC-NLOS system.The proposed method demonstrates millimeter-level imaging resolution when imaging horizontally and vertically striped objects.展开更多
The shadows similar to the vehicle and the spots caused by vehicle lamps need to be accurately detected in the vehicle segmentation involved in the video-based traffic parameter measurement. Generally, the road surfac...The shadows similar to the vehicle and the spots caused by vehicle lamps need to be accurately detected in the vehicle segmentation involved in the video-based traffic parameter measurement. Generally, the road surface is different from the vehicle surface in the gray-level architecture. An invariant gray-level architecture-the extremum image in the changing illumination environment is derived and a novel algorithm is presented for detecting shadows and spots. The gray-level structure that is not sensitive to the illumination is employed in the algorithm and the road surface mistaken as vehicles can be removed.展开更多
This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of t...This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of the polarization information of the target-reflected light into account and expands the application field of underwater polarization imaging.Independent component analysis was used to separate the target light and backscattered light. Theoretical analysis and proof-of-concept experiments were employed to demonstrate the effectiveness of the proposed method in estimating target information. The proposed method showed superiority in accurately estimating the target information compared with other polarization imaging methods.展开更多
基金supported by the Jilin Province Science and Technology Development Plan Item (No.20240402068GH)。
文摘To identify coatings and analyze the anti-detection capabilities of camouflage patterns, material samples can be prepared using the super-pixel segmentation method. A spectral polarization imaging system is developed, based on the principle of bidirectional reflectance distribution function(BRDF), to obtain spectral reflection intensities of coatings at full spatial angles, and use polarization images to calculate the refractive index by the Fresnel equation. The index is then coupled into TorranceSparrow model to simulate the spectral scattering intensity to mutually verify the experimental results. The spectral scattering characteristics of standard camouflage patterns are then revealed and pinpoint the signature band and the angle of reflecting sensitivity.
基金National Natural Science Foundation of China(Nos.11847069,11847127)Science Foundation of North University of China(No.XJJ20180030)。
文摘For conventional optical polarization imaging of underwater target,the polarization degree of backscatter should be pre-measured by averaging the pixel intensities in the no target region of the polarization images,and the polarization property of the target is assumed to be completely depolarized.When the scattering background is unseen in the field of view or the target is polarized,conventional method is helpless in detecting the target.An improvement is to use lots of co-polarization and cross polarization detection components.We propose a polarization subtraction method to estimate depolarization property of the scattering noise and target signal.And experiment in a quartz cuvette container is performed to demonstrate the effectiveness of the proposed method.The results show that the proposed method can work without scattering background reference,and further recover the target along with smooth surface for polarization preserving response.This study promotes the development of optical polarization imaging systems in underwater environments.
基金supported by the Guangming District Economic Development Special Fund(2020R01043).
文摘Ovarian cancer is one of the most aggressive and heterogeneous female tumors in the world,and serous ovarian cancer(SOC)is of particular concern for being the leading cause of ovarian cancer death.Due to its clinical and biological complexities,ovarian cancer is still considered one of the most di±cult tumors to diagnose and manage.In this study,three datasets were assembled,including 30 cases of serous cystadenoma(SCA),30 cases of serous borderline tumor(SBT),and 45 cases of serous adenocarcinoma(SAC).Mueller matrix microscopy is used to obtain the polarimetry basis parameters(PBPs)of each case,combined with a machine learning(ML)model to derive the polarimetry feature parameters(PFPs)for distinguishing serous ovarian tumor(SOT).The correlation between the mean values of PBPs and the clinicopathological features of serous ovarian cancer was analyzed.The accuracies of PFPs obtained from three types of SOT for identifying dichotomous groups(SCA versus SAC,SCA versus SBT,and SBT versus SAC)were 0.91,0.92,and 0.8,respectively.The accuracy of PFP for identifying triadic groups(SCA versus SBT versus SAC)was 0.75.Correlation analysis between PBPs and the clinicopathological features of SOC was performed.There were correlations between some PBPs(δ,β,q_(L),E_(2),rqcross,P_(2),P_(3),P_(4),and P_(5))and clinicopathological features,including the International Federation of Gynecology and Obstetrics(FIGO)stage,pathological grading,preoperative ascites,malignant ascites,and peritoneal implantation.The research showed that PFPs extracted from polarization images have potential applications in quantitatively differentiating the SOTs.These polarimetry basis parameters related to the clinicopathological features of SOC can be used as prognostic factors.
基金supported by National Natural Science Foundation of China(grants 60778044 and 10974114)Ministry of Science and Technology(grant 2006CB70570).
文摘Optical clearing improves the penetration depth of optical measurements in turbid tissues.Polarization imaging has been demonstrated as a potentially promising tool for detecting cancers in superficial tissues,but its limited depth of detection is a major obstacle to the effective application in clinical diagnosis.In the present paper,detection depths of two polarization imaging methods,i.e.,rotating linear polarization imaging(RLPI)and degree of polarization imaging(DOPI),are examined quantitatively using both experiments and Monte Carlo simulations.The results show that the contrast curves of RLPI and DOPI are different.The characteristic depth of DOPI scales with transport mean free path length,and that of RLPI increases slightly with g.Both characteristic depths of RLPI and DOPI are on the order of transport mean free path length and the former is almost twice as large as the latter.It is expected that they should have different response to optical clearing process in tissues.
基金supported by the National Natural Science Foundation of China(NSFC)Grant Nos.10974114,11174178,61205199the Knowledge Innovation Program of Basic Research Projects of Shenzhen Grant No.JCY20130402145002404.
文摘The contrast mechanism of different polarization imaging techniques for melanoma in mouse skin is st udied using both experiments and Monte Carlo simulations.Total intensity,linear polariz-ation diference imaging(DPI),degree of polarization imaging(DOPI)and'rotating linearpolarization imaging(RLPl)are applied and the relative contrasts of these polarization imagingmethods between the normal and cancerous tissues are compared.A two-layer absorption-scat-tering model is proposed to explain the contrast mechanism of the polarization imaging formelanoma.By taking into account of both scattering of symmetrical and asymmetrical scat terersand absorption of inter-scatterer medium,the two-layer model reproduces the relative con trastsfor polarization images observed in experiments.The simulation results also show that,theparameters of polarization imaging change more dramatically with the variation of absorption inthe bottom layer than the top layer.
基金supported by the National Natural Science Foundation of China(NSFC)Grants No.10974114,11174178,41106034Open Fund of Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes,Jinan University.
文摘We apply diferent polarization imaging techniques for cancerous liver tissues,and compare the relative contrasts for difference polarization imaging(DPI),degree of polarization imaging(DOPI)and rotating linear polarization imaging(RLPI).Experimental results show that a number of polarization imaging parameters are capable of differentiating cancerous cells in isotropic liver tisues.To analyze the contrast mechanism of the cancer:-sensitive polarization imaging parameters,we propose a scattering model cont aining two types of spherical scatterers and carry on Monte Carlo simula tions based on this bi-component model.Both the experimental and Monte Carlo simulated results show that the RLPI technique can provide a good imaging contrast of cancerous tissues.The bi-component scattering model provides a useful tool to ana-lyze the contrast mechanism of polarization imaging of cancerous tissues.
基金Doctoral Fund Project of Henan Polytechnic University(No.B2019-20)Key Scientific Research Projects of Henan Colleges and Universities(Nos.21A510004,20B430005)Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JM6008)。
文摘Differential polarization imaging has been widely used to selectively probe the target embedded in turbid medium.A thorough understanding of image quality involved in differential polarization imaging is essential for practical use.Using polarized light Monte Carlo simulations,it has been investigated how the state of polarization of incident light and the optical properties of scattering medium affect the image contrast.The contrast for linear polarization is similar to that for circular polarization in the isotropic medium comprising small-particles.The image quality is more pronounced for circular polarization in the isotropic medium containing large-particles and the birefringent medium.Furthermore,differential polarization imaging provides better image quality for the birefringent medium compared with isotropic medium.The effect of particle-size and birefringence on the polarization characteristics of target light and backscattered light is investigated.With the help of numerical results,the polarization characteristics of target light and backscattered light,the image quality is well explained in the turbid medium mentioned above.
基金National Natural Science Foundation of China(62171467)Natural Science Foundation of Hebei Province(F2021506004)。
文摘Recently,infrared polarization imaging technology has become a research hotspot due to its ability to better resolve the physicochemical properties of objects and significantly enhance the target characteristics.However,the traditional infrared polarization imaging is limited to similar imaging mechanism restrictions,and it is difficult to acquire the polarization information of a wide-area posture in real time.Therefore,we report a combination of hardware and software for super-wide-field-of-view long-wave infrared gaze polarization imaging technology.Utilizing the non-similar imaging theory and adopting the inter-lens coupling holographic linegrid infrared polarization device scheme,we designed the infrared gazing polarized lens with a field-of-view of over 160°.Based on the fusion of infrared intensity images and infrared polarization images,a multi-strategy detail feature extraction and fusion network is constructed.Super-wide-field-of-view(150°×120°),large face array(1040×830),detail-rich infrared fusion images are acquired during the test.We have accomplished the tasks of vehicle target detection and infrared camouflage target recognition efficiently using the fusion images,and verified the superiority of recognizing far-field targets.Our implementation should enable and empower applications in machine vision,intelligent driving,and target detection under complex environments.
基金supported by the National Key Research and Development Program of China(No.2022YFA1404800)the National Natural Science Foundation of China(Nos.12474298,12174309,and 12074313)+2 种基金the Natural Science Basic Research Program of Shaanxi(No.2025-JC-JCQN-063)the Fundamental Research Funds for the Central Universities(No.5000230111)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2025022)。
文摘Extended depth-of-field(DoF)imaging enhances longitudinal clarity but traditionally fails to record polarization information.Here,we propose a liquid-crystal Pancharatnam-Berry(PB)phase element that extends DoF while sensing polarization ellipticity.Leveraging cubic-phase-induced defocus-insensitive point spread functions,a 10 cm DoF is achieved in a 10-cm-focal-length 4f system.Linear PB phases enable spin-orbit interactions to detect polarization states,overcoming irreversible polarization loss in conventional methods.This dual-functionality system integrates DoF extension with polarization sensing,enhancing multidimensional imaging capabilities and holding promise for advancing machine vision,microscopic imaging,and optical detection by merging depth clarity with polarization-based object differentiation.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.62335007.
文摘Asan emerging poserful tool to provide structural informstion af tissue specimens label-freely,Mueller matrix(MM)polarimetry has garnered extensive attention in biomedical studies and pathological diagnois.However,for the commonly used constant-step rotating MM polarimetricsystem,beam drift induæd by the rotation of polarization eements can lead to distortions in messurement results,severely affect ing MM imaging accuracy.Here,based on our previous study,we prоровe an optimizad self-registration method to mitigate the psæudo-depolarization effects introduced by image artifacts in constant-step rotatin g MM polarimetry.By addresing the prevalent issue of beam drift and image distortions in such polarimetric imaging systems,the effectivenes of the proposed method is experimentally validated using tissue samples.The result.s demonstrate a significant enhanæment in the accuIrsсy of depolarization parameter estimation after applying the optimized self-registration method.Furthermore,the method enhances the coarseness and contrsst of MM-derived parameters images,thereby bolstering their capacity to characterize tissuestructures.The optimized self-registration method proposed in this study can provide an innovstive spproach for quantitative tissue polarimetry bssæd on constant-step ro tating MM messurement,and contribute to the advanæment of polarimetric imaging technology in biomedical applications.
文摘The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact, quantification, rapidity, and high sensitivity, is expected to be used for auxiliary diagnosis of colorectal cancer. Herein, the differences in colorectal tissues of four pathological types were studied using this powerful technology. Polarized light imaging combined with the Mueller matrix decomposition (MMPD) method was applied to extract structural features that may be related to colorectal tumors. It demonstrated that parameters δ and θ could reflect the structural differences of colorectal tumors. Preliminary simulated experiment results revealed that the parameter δ was related to the fiber density, and the parameter θ was related to the fiber angle. Then Tamura image texture analysis was used to quantitatively describe tissues of different pathological types, and the results showed that the coarseness, contrast, directionality, and roughness of the four groups were statistically different. Texture analysis based on the quantitative data of the four dimensions could be applied for the identification of benign and malignant colorectal tumors.
基金Open Fund Project of Key Laboratory of Instrumentation Science&Dynamic Measurement(No.2DSYSJ2015005)Specialized Research Fund for the Doctoral Program of Ministry of Education Colleges(No.20121420110004)
文摘In view of the problem that current mainstream fusion method of infrared polarization image—Multiscale Geometry Analysis method only focuses on a certain characteristic to image representation.And spatial domain fusion method,Principal Component Analysis(PCA)method has the shortcoming of losing small target,this paper presents a new fusion method of infrared polarization images based on combination of Nonsubsampled Shearlet Transformation(NSST)and improved PCA.This method can make full use of the effectiveness to image details expressed by NSST and the characteristics that PCA can highlight the main features of images.The combination of the two methods can integrate the complementary features of themselves to retain features of targets and image details fully.Firstly,intensity and polarization images are decomposed into low frequency and high frequency components with different directions by NSST.Secondly,the low frequency components are fused with improved PCA,while the high frequency components are fused by joint decision making rule with local energy and local variance.Finally,the fused image is reconstructed with the inverse NSST to obtain the final fused image of infrared polarization.The experiment results show that the method proposed has higher advantages than other methods in terms of detail preservation and visual effect.
基金We are grateful for financial supports from National Key Research and Development Program of China(Grant No.2021YFF0502700)National Natural Science Foundation of China(Grant Nos.52275429,62205117,61835008)+1 种基金Knowledge Innovation Program of Wuhan-Shuguang,Innovation project of Optics Valley Laboratory(Grant No.OVL2021ZD002)Hubei Provincial Natural Science Foundation of China(Grant Nos.2020CFA004,2022CFB792).
文摘Multispectral and polarized focusing and imaging are key functions that are vitally important for a broad range of optical applications.Conventional techniques generally require multiple shots to unveil desired optical information and are implemented via bulky multi-pass systems or mechanically moving parts that are difficult to integrate into compact and integrated optical systems.Here,a design of ultra-compact transversely dispersive metalens capable of both spectrum and polarization ellipticity recognition and reconstruction in just a single shot is demonstrated with both coherent and incoherent light.Our design is well suited for integrated and high-speed optical information analysis and can significantly reduce the size and weight of conventional devices while simplifying the process of collecting optical information,thereby promising for various applications,including machine vision,minimized spectrometers,material characterization,remote sensing,and other areas which require comprehensive optical analysis.
基金Sponsored by the National High Technology Research and Development Program of China ("863"Program) (2006AA09Z207)
文摘Based on the characteristics that human eyes are sensitive to brightness and color, the lightness information of visible image and degree of linear polarization and polarization angle were fused in hue-saturation- value（HSV） space. To meet the observation of human eyes, hue adjustment based on color transfer was carried out to the fused image and hue was adjusted by polynomial fitting method. Hue adjustment method was improved considering the complicated real mapping relationship between hue gray scale of fused image and reference template image. The result shows that the color fusion method presented in this paper is superior to the traditional pseudo-color method and it is helpful to recognize the target from the environment correctly. The fusion result can reflect the difference of object＇s polarization characteristic, and get a natural fused image effect.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11974206 and 61527826).
文摘Mueller matrix imaging is emerging for the quantitative characterization of pathological microstructures and is especially sensitive to fibrous structures.Liver fibrosis is a characteristic of many types of chronic liver diseases.The clinical diagnosis of liver fibrosis requires time-consuming multiple staining processes that specifically target on fibrous structures.The staining proficiency of technicians and the subjective visualization of pathologists may bring inconsistency to clinical diagnosis.Mueller matrix imaging can reduce the multiple staining processes and provide quantitative diagnostic indicators to characterize liver fibrosis tissues.In this study,a fibersensitive polarization feature parameter(PFP)was derived through the forward sequential feature selection(SFS)and linear discriminant analysis(LDA)to target on the identification of fibrous structures.Then,the Pearson correlation coeffcients and the statistical T-tests between the fiber-sensitive PFP image textures and the liver fibrosis tissues were calculated.The results show the gray level run length matrix(GLRLM)-based run entropy that measures the heterogeneity of the PFP image was most correlated to the changes of liver fibrosis tissues at four stages with a Pearson correlation of 0.6919.The results also indicate the highest Pearson correlation of 0.9996 was achieved through the linear regression predictions of the combination of the PFP image textures.This study demonstrates the potential of deriving a fiber-sensitive PFP to reduce the multiple staining process and provide textures-based quantitative diagnostic indicators for the staging of liver fibrosis.
基金Shenzhen Key Fundamental Research Project(No.JCYJ20210324120012035).
文摘Recently,Mueller matrix(MM)polarimetric imaging-assisted pathology detection methods are showing great potential in clinical diagnosis.However,since our human eyes cannot observe polarized light directly,it raises a notable challenge for interpreting the measurement results by pathologists who have limited familiarity with polarization images.One feasible approach is to combine MM polarimetric imaging with virtual staining techniques to generate standardized stained images,inheriting the advantages of information-abundant MM polarimetric imaging.In this study,we develop a model using unpaired MM polarimetric images and bright-field images for generating standard hematoxylin and eosin(H&E)stained tissue images.Compared with the existing polarization virtual staining techniques primarily based on the model training with paired images,the proposed Cycle-Consistent Generative Adversarial Networks(CycleGAN)-based model simplifies data acquisition and data preprocessing to a great extent.The outcomes demonstrate the feasibility of training CycleGAN with unpaired polarization images and their corresponding bright-field images as a viable approach,which provides an intuitive manner for pathologists for future polarization-assisted digital pathology.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1203700)the National Natural Science Foundation of China(Grant Nos.62405129 and 62035008)+4 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20241197)the China Postdoctoral Science Foundation(Grant No.2024T170396)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240678)the Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2024ZB684)the Fundamental Research Funds for the Central Universities(Grant No.021314380244).
文摘Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present polarimeters usually perform a series of intensity measurements to carry out the polarization detection,making the process bulky and time-consuming.Thereby,compact and broadband-available polarimetry within a single snapshot is urgently demanded.We propose an all-liquid-crystal polarimeter for broadband polarization detection.It is cascaded by a q-plate and a polarization grating.The former is electrically tuned to meet the half-wave condition,whereas the latter is driven to deviate from this condition.After a polarized light passes through this device followed by a polarizer,its amplitude contrast and phase difference between orthogonal spins are read directly from the diffraction pattern.The intensity contrast between±1st orders depicts the amplitude contrast,whereas the rotating angle of the dark split reveals the phase difference.The Stokes parameters can be calculated accordingly.The polarimeter works in a broad spectral range of 470 to 1100 nm.Through presetting a q-plate array,polarization imaging is demonstrated.It supplies an all-liquid-crystal and full-visible-band tunable Stokes polarimeter that significantly promotes advances in polarization optics.
基金supported by the National Natural Science Foundation of China(Nos.62427803,62031018,and U23A20283)the Jiangsu Provincial Key Research and Development Program(No.BE2022391)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_0644)。
文摘Non-line-of-sight[NLOS]imaging enables the detection and reconstruction of hidden objects around corners,offering promising applications in autonomous driving,remote sensing,and medical diagnosis.However,existing steady-state NLOS imaging methods face challenges in achieving high efficiency and precision due to the need for multiple diffuse reflections and incomplete Fourier amplitude sampling.This study proposes,to our knowledge,a novel steady-state NLOS imaging technique via polarization differential correlography[PDC-NLOS].By employing the polarization difference of the laser speckle,the method designs a single-shot polarized speckle illumination strategy.The fast and stable real-time encoding for hidden objects ensures stable imaging quality of the PDC-NLOS system.The proposed method demonstrates millimeter-level imaging resolution when imaging horizontally and vertically striped objects.
文摘The shadows similar to the vehicle and the spots caused by vehicle lamps need to be accurately detected in the vehicle segmentation involved in the video-based traffic parameter measurement. Generally, the road surface is different from the vehicle surface in the gray-level architecture. An invariant gray-level architecture-the extremum image in the changing illumination environment is derived and a novel algorithm is presented for detecting shadows and spots. The gray-level structure that is not sensitive to the illumination is employed in the algorithm and the road surface mistaken as vehicles can be removed.
基金This work was supported by the Key Laboratory of Optical Engineering,Chinese Academy of Sciences(No.QC20191097)the National Natural Science Foundation of China(NSFC)(Nos.62075175 and 62005203).
文摘This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of the polarization information of the target-reflected light into account and expands the application field of underwater polarization imaging.Independent component analysis was used to separate the target light and backscattered light. Theoretical analysis and proof-of-concept experiments were employed to demonstrate the effectiveness of the proposed method in estimating target information. The proposed method showed superiority in accurately estimating the target information compared with other polarization imaging methods.
