Computed tomography has been proven to be useful for non-destructive inspection of structures and materials. We build a three-dimensional imaging system with the photonically generated incoherent noise source and the ...Computed tomography has been proven to be useful for non-destructive inspection of structures and materials. We build a three-dimensional imaging system with the photonically generated incoherent noise source and the Schottky barrier diode detector in the terahertz frequency band （90–140GHz）. Based on the computed tomography technique, the three-dimensional image of a ceramic sample is reconstructed successfully by stacking the slices at different heights. The imaging results not only indicate the ability of terahertz wave in the non-invasive sensing and non-destructive inspection applications, but also prove the effectiveness and superiority of the uni-traveling-carrier photodiode as a terahertz source in the imaging applications.展开更多
Array-based multi-modal surface wave imaging technology represents a significant breakthrough in the field of ambient noise surface wave imaging.By incorporating overtone surface wave dispersion curves,this method pro...Array-based multi-modal surface wave imaging technology represents a significant breakthrough in the field of ambient noise surface wave imaging.By incorporating overtone surface wave dispersion curves,this method provides new independent constraints for subsurface structure inversion,significantly enhancing the detection capability of low-velocity structures.However,when applied to 3D velocity structure imaging,the array-based surface wave method requires dividing the study area into multiple sub-arrays,imposing high demands on the number and spatial distribution density of stations.In practical applications,due to limitations such as geographical constraints,economic costs,and time,station deployment often struggles to meet these requirements.To address this technical bottleneck,this study innovatively proposes a single-array station pair random sampling method.This approach extracts dispersion curves by randomly selecting different combinations of station pairs from a single array and inverts the phase velocity distributions at spatial grid points by the spatial phase-velocity further inversion(SPFI) technology.This approach can achieve 3D velocity structure imaging of multi-modal surface waves based on a single array comprising only a few dozen stations.To validate the effectiveness of the method,we applied it to Zhaoshu Island in the Xisha Islands—a typical island area where station deployment is challenging.The imaging results clearly reveal three low-velocity layers near the surface,at 100 meters,and around 250 meters depth,which are highly consistent with island drilling data and the characteristics of reef growth controlled by sea-level changes.The new method proposed in this study significantly reduces the implementation cost of multi-mode surface wave imaging,improves its applicability in complex environments,and provides important technical support for subsequent in-depth research.展开更多
The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random t...The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random telegraph signal noise in the pixel source follower based on the binomial distribution is set up. The number of electrons captured or released by the oxide traps in the unit time is described as the random variables which obey the binomial distribution. As a result,the output states and the corresponding probabilities of the first and the second samples of the correlated double sampling circuit are acquired. The standard deviation of the output states after the correlated double sampling circuit can be obtained accordingly. In the simulation section, one hundred thousand samples of the source follower MOSFET have been simulated,and the simulation results show that the proposed model has the similar statistical characteristics with the existing models under the effect of the channel length and the density of the oxide trap. Moreover, the noise histogram of the proposed model has been evaluated at different environmental temperatures.展开更多
The discovery of dark noise in retinal photoreceptors resulted in a long-lasting controversy over its origin and the underlying mechanisms.Here,we used a novel ultra-weak biophoton imaging system（UBIS） to detect bio...The discovery of dark noise in retinal photoreceptors resulted in a long-lasting controversy over its origin and the underlying mechanisms.Here,we used a novel ultra-weak biophoton imaging system（UBIS） to detect biophotonic activity（emission） under dark conditions in rat and bullfrog（Rana catesbeiana） retinas in vitro.We found a significant temperature-dependent increase in biophotonic activity that was completely blocked either by removing intracellular and extracellular Ca^（2＋）together or inhibiting phosphodiesterase 6.These findings suggest that the photon-like component of discrete dark noise may not be caused by a direct contribution of the thermal activation of rhodopsin,but rather by an indirect thermal induction of biophotonic activity,which then activates the retinal chromophore of rhodopsin.Therefore,this study suggests a possible solution regarding the thermal activation energy barrier for discrete dark noise,which has been debated for almost half a century.展开更多
To overcome the problem of insufficient expression of fine texture when gradient mode is used as an image feature extraction operator in traditional PM model,which leads to excessive diffusion in these fine texture re...To overcome the problem of insufficient expression of fine texture when gradient mode is used as an image feature extraction operator in traditional PM model,which leads to excessive diffusion in these fine texture regions and texture ambiguity,this paper proposes ANRDPM(Anti-noise and Reverse Diffusion PM model)noise reduction model based on the new anti-noise coefficient and reverse diffusion concept.In this model,the meter gradient operator is used as the image feature extractor to solve the shortage of the traditional gradient operator in the ability to express details.Secondly,a new anti-noise coefficient based on Gaussian curvature and noise intensity is proposed to solve the problem that the meter gradient operator is allergic to large noise points.In addition,a reverse diffusion filter based on a local variance of residuals is introduced to enhance the smoothed texture information in the image.Finally,the new model is discretized by a finite difference algorithm,and simulation results show that the proposed ANRDPM model not only performs well in smoothing image noise,but also effectively protects image texture information and structural integrity.展开更多
The distribution of shear-wave velocities in the subsurface is generally used to assess the potential forseismic liquefaction and soil amplification effects and to classify seismic sites. Newly developeddistributed ac...The distribution of shear-wave velocities in the subsurface is generally used to assess the potential forseismic liquefaction and soil amplification effects and to classify seismic sites. Newly developeddistributed acoustic sensing (DAS) technology enables estimation of the shear-wave distribution as ahigh-density seismic observation system. This technology is characterized by low maintenance costs,high-resolution outputs, and real-time data transmission capabilities, albeit with the challenge ofmanaging massive data generation. Rapid and efficient interpretation of data is the key to advancingapplication of the DAS technology. In this study, field tests were carried out to record ambient noise overa short period using DAS technology, from which the surface-wave dispersion curves were extracted. Inorder to reduce the influence of directional effects on the results, an unsupervised clustering method isused to select appropriate clusters to extract the Green's function. A combination of a genetic algorithmand Monte Carlo (GA-MC) simulation is proposed to invert the subsurface velocity structure. Thestratigraphic profiles obtained by the GA-MC method are in agreement with the borehole profiles.Compared to other methods, the proposed optimization method not only improves the solution qualitybut also reduces the solution time.展开更多
Computed tomography colonography(CTC)has become a key examination in detecting colonic polyps and colorectal carcinoma(CRC).It is particularly useful after incomplete optical colonoscopy(OC)for patients with sedation ...Computed tomography colonography(CTC)has become a key examination in detecting colonic polyps and colorectal carcinoma(CRC).It is particularly useful after incomplete optical colonoscopy(OC)for patients with sedation risks and patients anxious about the risks or potential discomfort associated with OC.CTC's main advantages compared with OC are its non-invasive nature,better patient compliance,and the ability to assess the extracolonic disease.Despite these advantages,ionizing radiation remains the most significant burden of CTC.This opinion review comprehensively addresses the radiation risk of CTC,incorporating imaging technology refinements such as automatic tube current modulation,filtered back projections,lowering the tube voltage,and iterative reconstructions as tools for optimizing low and ultra-low dose protocols of CTC.Future perspectives arise from integrating artificial intelligence in computed tomography machines for the screening of CRC.展开更多
In this paper,an image processing method for improving the quality of optical coherence tomography(OCT)images is proposed.Wavelet denoising based on context modeling and contrast enhancement by means of the contrast m...In this paper,an image processing method for improving the quality of optical coherence tomography(OCT)images is proposed.Wavelet denoising based on context modeling and contrast enhancement by means of the contrast measure in the wavelet domain is carried out on the OCT images in succession.Three parameters are selected to assess the effectiveness of the method.It is shown from the results that the proposed method can not only enhance the contrast of images,but also improve signal-to-noise ratio.Compared with two other typical algorithms,it has the best visual effect.展开更多
Objectives:When detecting changes in synthetic aperture radar(SAR)images,the quality of the difference map has an important impact on the detection results,and the speckle noise in the image interferes with the extrac...Objectives:When detecting changes in synthetic aperture radar(SAR)images,the quality of the difference map has an important impact on the detection results,and the speckle noise in the image interferes with the extraction of change information.In order to improve the detection accuracy of SAR image change detection and improve the quality of the difference map,this paper proposes a method that combines the popular deep neural network with the clustering algorithm.Methods:Firstly,the SAR image with speckle noise was constructed,and the FFDNet architecture was used to retrain the SAR image,and the network parameters with better effect on speckle noise suppression were obtained.Then the log ratio operator is generated by using the reconstructed image output from the network.Finally,K-means and FCM clustering algorithms are used to analyze the difference images,and the binary map of change detection results is generated.Results:The experimental results have high detection accuracy on Bern and Sulzberger’s real data,which proves the effectiveness of the method.展开更多
Aiming at the problem that the traditional watershed image segmentation algorithm is sensitive to noise and prone to ＂over-segmentation＂, an image segmentation method based on improved watershed algorithm is propose...Aiming at the problem that the traditional watershed image segmentation algorithm is sensitive to noise and prone to ＂over-segmentation＂, an image segmentation method based on improved watershed algorithm is proposed. First, the denoising method is used to denoise the tea image by using the differential equation denoising model The interference of the image on the image segmentation, the protection of the tea image of the edge of the tea information; and then use the watershed algorithm to denoise the tea image after the split. The simulation results show that this method can effectively avoid the influence of noise on image segmentation, and get a good image of ,louug leaves of tea image.展开更多
Skin lesions are in a category of disease that is both common in humans and a major cause of death.The classification accuracy of skin lesions is a crucial determinant of the success rate of curing lethal diseases.Dee...Skin lesions are in a category of disease that is both common in humans and a major cause of death.The classification accuracy of skin lesions is a crucial determinant of the success rate of curing lethal diseases.Deep Convolutional Neural Networks(CNNs)are now the most prevalent computer algorithms for the purpose of disease classification.As with all algorithms,CNNs are sensitive to noise from imaging devices,which often contaminates the quality of the images that are fed into them.In this paper,a deep CNN(Inception-v3)is used to study the effect of image noise on the classification of skin lesions.Gaussian noise,impulse noise,and noise made up of a compound of the two are added to an image dataset,namely the Dermofit Image Library from the University of Edinburgh.Evaluations,based on t-distributed Stochastic Neighbor Embedding(t-SNE)visualization,Receiver Operating Characteristic(ROC)analysis,and saliency maps,demonstrate the reliability of the Inception-v3 deep CNN in classifying noisy skin lesion images.展开更多
One of the main drawbacks of Digital Holography(DH)is the coherent nature of the light source,which severely corrupts the quality of holographic reconstructions.Although numerous techniques to reduce noise in DH have ...One of the main drawbacks of Digital Holography(DH)is the coherent nature of the light source,which severely corrupts the quality of holographic reconstructions.Although numerous techniques to reduce noise in DH have provided good results,holographic noise suppression remains a challenging task.We propose a novel framework that combines the concepts of encoding multiple uncorrelated digital holograms,block grouping and collaborative filtering to achieve quasi noise-free DH reconstructions.The optimized joint action of these different image-denoising methods permits the removal of up to 98%of the noise while preserving the image contrast.The resulting quality of the hologram reconstructions is comparable to the quality achievable with non-coherent techniques and far beyond the current state of art in DH.Experimental validation is provided for both singlewavelength and multi-wavelength DH,and a comparison with the most used holographic denoising methods is performed.展开更多
There are various applied electro-optical devices, which utilize light emitting didoe(LED) chip array for applications to displays and opto-electronic sensors. In those devices, it is the one of the critical technical...There are various applied electro-optical devices, which utilize light emitting didoe(LED) chip array for applications to displays and opto-electronic sensors. In those devices, it is the one of the critical technical issues to minimize uncertain fluctuations including optical power and optical density. Due to variation in operating environment of a device, those are not corrected precisely by controlling parameters based on simple relation between parameters and resultant abovementioned outputs.Therefore, there is essential need to correct outputs in real-time based on correction function generated from the consideration on various operation condition. In this article, we introduce an output correction method through reporting real-time image noise reduction in the application to electro-photography with LED print head. In the technology of LED print head, as differences in optical characteristics between each LED cause vertical image noise, it should be corrected in order to obtain images that are comparable or better in quality compared to those produced by the conventional laser scanning method. Even though it seems that the method used to obtain uniform light power from each LED can solve this problem, it does not work well for high-resolution printing. Therefore, a scan method involving correction by a printed and scanned pattern is introduced through this work. The scan method is composed of correction patterns to minimize printing noise by its shape, the correction algorithm to calculate the optimized value and the printing algorithm to control gray levels in real-time precisely. We believe that the developed correction method upgrades the printing quality of the LPH printer better than commercial printers. The developed correction method can also be applied to various application areas that use an array-type light source such as display systems and lighting systems.展开更多
基金Supported by the Hundred Talents Program of Chinese Academy of Sciencesthe National Basic Research Program of China under Grant No 2014CB339803+2 种基金the Major National Development Project of Scientific Instrument and Equipment under Grant No2011YQ150021the National Natural Science Foundation of China under Grant Nos 61575214,61574155,61404149 and 61404150the Shanghai Municipal Commission of Science and Technology under Grant Nos 14530711300,15560722000 and 15ZR1447500
文摘Computed tomography has been proven to be useful for non-destructive inspection of structures and materials. We build a three-dimensional imaging system with the photonically generated incoherent noise source and the Schottky barrier diode detector in the terahertz frequency band （90–140GHz）. Based on the computed tomography technique, the three-dimensional image of a ceramic sample is reconstructed successfully by stacking the slices at different heights. The imaging results not only indicate the ability of terahertz wave in the non-invasive sensing and non-destructive inspection applications, but also prove the effectiveness and superiority of the uni-traveling-carrier photodiode as a terahertz source in the imaging applications.
基金supported by the National Key Research and Development Program of China(Grant No.2022-22)the National Natural Science Foundation of China(Grant Nos.42374062, 42430102, 42206068)the Independent Research Project of the South China Sea Institute of Oceanology,Chinese Academy of Sciences(Grant No.SCSIO2023QY05)。
文摘Array-based multi-modal surface wave imaging technology represents a significant breakthrough in the field of ambient noise surface wave imaging.By incorporating overtone surface wave dispersion curves,this method provides new independent constraints for subsurface structure inversion,significantly enhancing the detection capability of low-velocity structures.However,when applied to 3D velocity structure imaging,the array-based surface wave method requires dividing the study area into multiple sub-arrays,imposing high demands on the number and spatial distribution density of stations.In practical applications,due to limitations such as geographical constraints,economic costs,and time,station deployment often struggles to meet these requirements.To address this technical bottleneck,this study innovatively proposes a single-array station pair random sampling method.This approach extracts dispersion curves by randomly selecting different combinations of station pairs from a single array and inverts the phase velocity distributions at spatial grid points by the spatial phase-velocity further inversion(SPFI) technology.This approach can achieve 3D velocity structure imaging of multi-modal surface waves based on a single array comprising only a few dozen stations.To validate the effectiveness of the method,we applied it to Zhaoshu Island in the Xisha Islands—a typical island area where station deployment is challenging.The imaging results clearly reveal three low-velocity layers near the surface,at 100 meters,and around 250 meters depth,which are highly consistent with island drilling data and the characteristics of reef growth controlled by sea-level changes.The new method proposed in this study significantly reduces the implementation cost of multi-mode surface wave imaging,improves its applicability in complex environments,and provides important technical support for subsequent in-depth research.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61372156 and 61405053)the Natural Science Foundation of Zhejiang Province of China(Grant No.LZ13F04001)
文摘The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random telegraph signal noise in the pixel source follower based on the binomial distribution is set up. The number of electrons captured or released by the oxide traps in the unit time is described as the random variables which obey the binomial distribution. As a result,the output states and the corresponding probabilities of the first and the second samples of the correlated double sampling circuit are acquired. The standard deviation of the output states after the correlated double sampling circuit can be obtained accordingly. In the simulation section, one hundred thousand samples of the source follower MOSFET have been simulated,and the simulation results show that the proposed model has the similar statistical characteristics with the existing models under the effect of the channel length and the density of the oxide trap. Moreover, the noise histogram of the proposed model has been evaluated at different environmental temperatures.
基金supported by the National Natural Science Foundation of China (31070961)the Sci-Tech Support Plan of Hubei Province,China (2014BEC086)the Research Team Fund of South Central University for Nationalities,China (XTZ15014)
文摘The discovery of dark noise in retinal photoreceptors resulted in a long-lasting controversy over its origin and the underlying mechanisms.Here,we used a novel ultra-weak biophoton imaging system（UBIS） to detect biophotonic activity（emission） under dark conditions in rat and bullfrog（Rana catesbeiana） retinas in vitro.We found a significant temperature-dependent increase in biophotonic activity that was completely blocked either by removing intracellular and extracellular Ca^（2＋）together or inhibiting phosphodiesterase 6.These findings suggest that the photon-like component of discrete dark noise may not be caused by a direct contribution of the thermal activation of rhodopsin,but rather by an indirect thermal induction of biophotonic activity,which then activates the retinal chromophore of rhodopsin.Therefore,this study suggests a possible solution regarding the thermal activation energy barrier for discrete dark noise,which has been debated for almost half a century.
基金funded by National Nature Science Foundation of China,grant number 61302188.
文摘To overcome the problem of insufficient expression of fine texture when gradient mode is used as an image feature extraction operator in traditional PM model,which leads to excessive diffusion in these fine texture regions and texture ambiguity,this paper proposes ANRDPM(Anti-noise and Reverse Diffusion PM model)noise reduction model based on the new anti-noise coefficient and reverse diffusion concept.In this model,the meter gradient operator is used as the image feature extractor to solve the shortage of the traditional gradient operator in the ability to express details.Secondly,a new anti-noise coefficient based on Gaussian curvature and noise intensity is proposed to solve the problem that the meter gradient operator is allergic to large noise points.In addition,a reverse diffusion filter based on a local variance of residuals is introduced to enhance the smoothed texture information in the image.Finally,the new model is discretized by a finite difference algorithm,and simulation results show that the proposed ANRDPM model not only performs well in smoothing image noise,but also effectively protects image texture information and structural integrity.
基金supported by the National Natural Science Foundation of China(Grant Nos.42225702 and 42077235)the Natural Science Foundation of Jiangsu Province(Grant No.BK20211086)the open fund of the Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources.
文摘The distribution of shear-wave velocities in the subsurface is generally used to assess the potential forseismic liquefaction and soil amplification effects and to classify seismic sites. Newly developeddistributed acoustic sensing (DAS) technology enables estimation of the shear-wave distribution as ahigh-density seismic observation system. This technology is characterized by low maintenance costs,high-resolution outputs, and real-time data transmission capabilities, albeit with the challenge ofmanaging massive data generation. Rapid and efficient interpretation of data is the key to advancingapplication of the DAS technology. In this study, field tests were carried out to record ambient noise overa short period using DAS technology, from which the surface-wave dispersion curves were extracted. Inorder to reduce the influence of directional effects on the results, an unsupervised clustering method isused to select appropriate clusters to extract the Green's function. A combination of a genetic algorithmand Monte Carlo (GA-MC) simulation is proposed to invert the subsurface velocity structure. Thestratigraphic profiles obtained by the GA-MC method are in agreement with the borehole profiles.Compared to other methods, the proposed optimization method not only improves the solution qualitybut also reduces the solution time.
文摘Computed tomography colonography(CTC)has become a key examination in detecting colonic polyps and colorectal carcinoma(CRC).It is particularly useful after incomplete optical colonoscopy(OC)for patients with sedation risks and patients anxious about the risks or potential discomfort associated with OC.CTC's main advantages compared with OC are its non-invasive nature,better patient compliance,and the ability to assess the extracolonic disease.Despite these advantages,ionizing radiation remains the most significant burden of CTC.This opinion review comprehensively addresses the radiation risk of CTC,incorporating imaging technology refinements such as automatic tube current modulation,filtered back projections,lowering the tube voltage,and iterative reconstructions as tools for optimizing low and ultra-low dose protocols of CTC.Future perspectives arise from integrating artificial intelligence in computed tomography machines for the screening of CRC.
基金supported by the National Natural Science Foundation of China(Grant Nos.60637020 and 60677012)the Tianjin Foundation of Natural Science(No.09JCZDJC18300).
文摘In this paper,an image processing method for improving the quality of optical coherence tomography(OCT)images is proposed.Wavelet denoising based on context modeling and contrast enhancement by means of the contrast measure in the wavelet domain is carried out on the OCT images in succession.Three parameters are selected to assess the effectiveness of the method.It is shown from the results that the proposed method can not only enhance the contrast of images,but also improve signal-to-noise ratio.Compared with two other typical algorithms,it has the best visual effect.
文摘Objectives:When detecting changes in synthetic aperture radar(SAR)images,the quality of the difference map has an important impact on the detection results,and the speckle noise in the image interferes with the extraction of change information.In order to improve the detection accuracy of SAR image change detection and improve the quality of the difference map,this paper proposes a method that combines the popular deep neural network with the clustering algorithm.Methods:Firstly,the SAR image with speckle noise was constructed,and the FFDNet architecture was used to retrain the SAR image,and the network parameters with better effect on speckle noise suppression were obtained.Then the log ratio operator is generated by using the reconstructed image output from the network.Finally,K-means and FCM clustering algorithms are used to analyze the difference images,and the binary map of change detection results is generated.Results:The experimental results have high detection accuracy on Bern and Sulzberger’s real data,which proves the effectiveness of the method.
文摘Aiming at the problem that the traditional watershed image segmentation algorithm is sensitive to noise and prone to ＂over-segmentation＂, an image segmentation method based on improved watershed algorithm is proposed. First, the denoising method is used to denoise the tea image by using the differential equation denoising model The interference of the image on the image segmentation, the protection of the tea image of the edge of the tea information; and then use the watershed algorithm to denoise the tea image after the split. The simulation results show that this method can effectively avoid the influence of noise on image segmentation, and get a good image of ,louug leaves of tea image.
文摘Skin lesions are in a category of disease that is both common in humans and a major cause of death.The classification accuracy of skin lesions is a crucial determinant of the success rate of curing lethal diseases.Deep Convolutional Neural Networks(CNNs)are now the most prevalent computer algorithms for the purpose of disease classification.As with all algorithms,CNNs are sensitive to noise from imaging devices,which often contaminates the quality of the images that are fed into them.In this paper,a deep CNN(Inception-v3)is used to study the effect of image noise on the classification of skin lesions.Gaussian noise,impulse noise,and noise made up of a compound of the two are added to an image dataset,namely the Dermofit Image Library from the University of Edinburgh.Evaluations,based on t-distributed Stochastic Neighbor Embedding(t-SNE)visualization,Receiver Operating Characteristic(ROC)analysis,and saliency maps,demonstrate the reliability of the Inception-v3 deep CNN in classifying noisy skin lesion images.
基金supported by DATABENC_Progetto SNECS-PON03PE_00163_1 Social Network delle Entitàdei Centri Storici.
文摘One of the main drawbacks of Digital Holography(DH)is the coherent nature of the light source,which severely corrupts the quality of holographic reconstructions.Although numerous techniques to reduce noise in DH have provided good results,holographic noise suppression remains a challenging task.We propose a novel framework that combines the concepts of encoding multiple uncorrelated digital holograms,block grouping and collaborative filtering to achieve quasi noise-free DH reconstructions.The optimized joint action of these different image-denoising methods permits the removal of up to 98%of the noise while preserving the image contrast.The resulting quality of the hologram reconstructions is comparable to the quality achievable with non-coherent techniques and far beyond the current state of art in DH.Experimental validation is provided for both singlewavelength and multi-wavelength DH,and a comparison with the most used holographic denoising methods is performed.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government(Grant No.2015R1C1A1A01053888)the Yeungnam University Research Grant(Grant No.216A580022)
文摘There are various applied electro-optical devices, which utilize light emitting didoe(LED) chip array for applications to displays and opto-electronic sensors. In those devices, it is the one of the critical technical issues to minimize uncertain fluctuations including optical power and optical density. Due to variation in operating environment of a device, those are not corrected precisely by controlling parameters based on simple relation between parameters and resultant abovementioned outputs.Therefore, there is essential need to correct outputs in real-time based on correction function generated from the consideration on various operation condition. In this article, we introduce an output correction method through reporting real-time image noise reduction in the application to electro-photography with LED print head. In the technology of LED print head, as differences in optical characteristics between each LED cause vertical image noise, it should be corrected in order to obtain images that are comparable or better in quality compared to those produced by the conventional laser scanning method. Even though it seems that the method used to obtain uniform light power from each LED can solve this problem, it does not work well for high-resolution printing. Therefore, a scan method involving correction by a printed and scanned pattern is introduced through this work. The scan method is composed of correction patterns to minimize printing noise by its shape, the correction algorithm to calculate the optimized value and the printing algorithm to control gray levels in real-time precisely. We believe that the developed correction method upgrades the printing quality of the LPH printer better than commercial printers. The developed correction method can also be applied to various application areas that use an array-type light source such as display systems and lighting systems.
