To eliminate rotation deviation of sequential images mosaic when measuring linear dimensions of large scale parts with computer vision, a novel algorithm based on the chain code searching method is proposed. After ima...To eliminate rotation deviation of sequential images mosaic when measuring linear dimensions of large scale parts with computer vision, a novel algorithm based on the chain code searching method is proposed. After image preprocessing, including image filtering, image segmentation, and edge detection, the chain code length of the contour line can be searched out by the proposed method. Then, the angle from the contour line to the coordinate axis is computed with the length of the contour line. After that, the sequence is rotated in the opposite direction and the rotation deviation is eliminated. It is prepared for the next mosaic of sequences in eliminating shifting deviation. Experiments are carried out on parts with a linear profile rotating angle from 0° to 9°. The results show that compared with the commonly used Hough transform, the new method has higher precision and faster speed, which is important in realizing online high precision measurements of large scale parts with a linear profile.展开更多
Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot...Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot be processed on deep space probes, thus the rich landmark features in the sequential images must be selected. The contribution of landmark features to navigation accuracy is usually measured in terms of observability degrees, but the traditional method only observes the locally optimal landmarks at a single moment, and the navigation accuracy will be affected by the gradual decrease of observability degrees when observing the same landmark several times in a row before landmarks are reoptimized. In this paper, we first establish of autonomous navigation model of planetary landing segment based on sequential images. Then we construct a sequential image observability degree for multiple observations, proving that it is a convex function, and giving the interval of the minimum value point, which guides the selection of landmarks with the highest observability for multiple moments. Finally, numerical simulations were conducted and verified that using sequential image observability degree to optimize landmarks for navigation can achieve higher navigation accuracy than traditional single moment selection methods, and it can provide theoretical support for the sequential image autonomous navigation in the landing segment of deep space exploration.展开更多
Microstructural classification is typically done manually by human experts,which gives rise to uncertainties due to subjectivity and reduces the overall efficiency.A high-throughput characterization is proposed based ...Microstructural classification is typically done manually by human experts,which gives rise to uncertainties due to subjectivity and reduces the overall efficiency.A high-throughput characterization is proposed based on deep learning,rapid acquisition technology,and mathematical statistics for the recognition,segmentation,and quantification of microstructure in weathering steel.The segmentation results showed that this method was accurate and efficient,and the segmentation of inclusions and pearlite phase achieved accuracy of 89.95%and 90.86%,respectively.The time required for batch processing by MIPAR software involving thresholding segmentation,morphological processing,and small area deletion was 1.05 s for a single image.By comparison,our system required only 0.102 s,which is ten times faster than the commercial software.The quantification results were extracted from large volumes of sequential image data(150 mm^(2),62,216 images,1024×1024 pixels),which ensure comprehensive statistics.Microstructure information,such as three-dimensional density distribution and the frequency of the minimum spatial distance of inclusions on the sample surface of 150 mm^(2),were quantified by extracting the coordinates and sizes of individual features.A refined characterization method for two-dimensional structures and spatial information that is unattainable when performing manually or with software is provided.That will be useful for understanding properties or behaviors of weathering steel,and reducing the resort to physical testing.展开更多
A series of NOAA AVHRR data over the East China Sea were collected from the ground station of the Second Institute of Oceanography, Hangzhou, China. Three methods, including a functional analytic method (FAM), a maxim...A series of NOAA AVHRR data over the East China Sea were collected from the ground station of the Second Institute of Oceanography, Hangzhou, China. Three methods, including a functional analytic method (FAM), a maximum cross correlation (MCC)'method and a correlation relaxation (C - R) method, are applied to derive the sea surface current field from sequential satellite images in the area of the East China Sea. Several preprocessing steps, such as geometric correction, SST determination, image projection, image navigation and grey value normalization as well as land and cloud mask are performed. The results from the three methods reflect the general current system in this area reasonably.展开更多
To realize the high-precision vision measurement for large scale machine parts, a new vision measurement method based on dimension features of sequential partial images is proposed. Instead of mosaicking the partial i...To realize the high-precision vision measurement for large scale machine parts, a new vision measurement method based on dimension features of sequential partial images is proposed. Instead of mosaicking the partial images, extracting the dimension features of the sequential partial images and deriving the part size according to the relationships between the sequential images is a novel method to realize the high- precision and fast measurement of machine parts. To overcome the corresponding problems arising from the relative rotation between two sequential partial images, a rectifying method based on texture features is put forward to effectively improve the processing speed. Finally, a case study is provided to demonstrate the analysis procedure and the effectiveness of the proposed method. The experiments show that the relative error is less than 0. 012% using the sequential image measurement method to gauge large scale straight-edge parts. The measurement precision meets the needs of precise measurement for sheet metal parts.展开更多
The growth patterns of mammary fat pads and glandular tissues inside the fat pads may be related with the risk factors of breast cancer.Quantitative measurements of this relationship are available after segmentation o...The growth patterns of mammary fat pads and glandular tissues inside the fat pads may be related with the risk factors of breast cancer.Quantitative measurements of this relationship are available after segmentation of mammary pads and glandular tissues.Rat fat pads may lose continuity along image sequences or adjoin similar intensity areas like epidermis and subcutaneous regions.A new approach for automatic tracing and segmentation of fat pads in magnetic resonance imaging(MRI) image sequences is presented,which does not require that the number of pads be constant or the spatial location of pads be adjacent among image slices.First,each image is decomposed into cartoon image and texture image based on cartoon-texture model.They will be used as smooth image and feature image for segmentation and for targeting pad seeds,respectively.Then,two-phase direct energy segmentation based on Chan-Vese active contour model is applied to partitioning the cartoon image into a set of regions,from which the pad boundary is traced iteratively from the pad seed.A tracing algorithm based on scanning order is proposed to accurately trace the pad boundary,which effectively removes the epidermis attached to the pad without any post processing as well as solves the problem of over-segmentation of some small holes inside the pad.The experimental results demonstrate the utility of this approach in accurate delineation of various numbers of mammary pads from several sets of MRI images.展开更多
This letter presents an autofocus （AF） method to position a high-magnification microscope lens that automatically captures hundreds of images from a single moving slide. These images are taken by a mobile clinic uni...This letter presents an autofocus （AF） method to position a high-magnification microscope lens that automatically captures hundreds of images from a single moving slide. These images are taken by a mobile clinic unit in a rural location, and are later automatically processed and revised by a remote specialist. This process requires high focus precision to enable image processing techniques to achieve proper results. Low focusing times are also required for the system to be operative. We propose a novel method that combines two focus measures with an adapted searching scheme to cope with both constraints.展开更多
We propose a computational method for generating sequential kinoforms of real-existing full-color three- dimensional （3D） objects and realizing high-quality 3D imaging. The depth map and color information are obtain...We propose a computational method for generating sequential kinoforms of real-existing full-color three- dimensional （3D） objects and realizing high-quality 3D imaging. The depth map and color information are obtained using non-contact full-color 3D measurement system based on binocular vision. The obtained full-color 3D data are decomposed into multiple slices with RGB channels. Sequential kinoforms of each channel are calculated and reconstructed using a Fresnel-diffraction-based algorithm called the dynamic- pseudorandom-phase tomographic computer holography （DPP-TCH）. Color dispersion introduced by different wavelengths is well compensated by zero-padding operation in the red and green channels of object slices. Numerical reconstruction results show that the speckle noise and color-dispersion are well suppressed and that high-quality full-color holographic 3D imaging is feasible. The method is useful for improving the 3D image quality in holographic displays with pixelated phase-type spatial light modulators （SLMs）.展开更多
基金The National Natural Science Foundation of China(No.50805023)the Program for Special Talent in Six Fields of Jiangsu Province(No.2008144)Jiangsu Provincial Science and Technology Achievement Transformation Project(No.BA2010093)
文摘To eliminate rotation deviation of sequential images mosaic when measuring linear dimensions of large scale parts with computer vision, a novel algorithm based on the chain code searching method is proposed. After image preprocessing, including image filtering, image segmentation, and edge detection, the chain code length of the contour line can be searched out by the proposed method. Then, the angle from the contour line to the coordinate axis is computed with the length of the contour line. After that, the sequence is rotated in the opposite direction and the rotation deviation is eliminated. It is prepared for the next mosaic of sequences in eliminating shifting deviation. Experiments are carried out on parts with a linear profile rotating angle from 0° to 9°. The results show that compared with the commonly used Hough transform, the new method has higher precision and faster speed, which is important in realizing online high precision measurements of large scale parts with a linear profile.
基金supported by the National Natural Science Foundation of China(Grant Number U20B2055)the National Natural Science Fund for Distinguished Young Scholars of China(Grant Number 61525301)
文摘Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot be processed on deep space probes, thus the rich landmark features in the sequential images must be selected. The contribution of landmark features to navigation accuracy is usually measured in terms of observability degrees, but the traditional method only observes the locally optimal landmarks at a single moment, and the navigation accuracy will be affected by the gradual decrease of observability degrees when observing the same landmark several times in a row before landmarks are reoptimized. In this paper, we first establish of autonomous navigation model of planetary landing segment based on sequential images. Then we construct a sequential image observability degree for multiple observations, proving that it is a convex function, and giving the interval of the minimum value point, which guides the selection of landmarks with the highest observability for multiple moments. Finally, numerical simulations were conducted and verified that using sequential image observability degree to optimize landmarks for navigation can achieve higher navigation accuracy than traditional single moment selection methods, and it can provide theoretical support for the sequential image autonomous navigation in the landing segment of deep space exploration.
基金supported by the National Key Research and Development Program of China(No.2017YFB0702303).
文摘Microstructural classification is typically done manually by human experts,which gives rise to uncertainties due to subjectivity and reduces the overall efficiency.A high-throughput characterization is proposed based on deep learning,rapid acquisition technology,and mathematical statistics for the recognition,segmentation,and quantification of microstructure in weathering steel.The segmentation results showed that this method was accurate and efficient,and the segmentation of inclusions and pearlite phase achieved accuracy of 89.95%and 90.86%,respectively.The time required for batch processing by MIPAR software involving thresholding segmentation,morphological processing,and small area deletion was 1.05 s for a single image.By comparison,our system required only 0.102 s,which is ten times faster than the commercial software.The quantification results were extracted from large volumes of sequential image data(150 mm^(2),62,216 images,1024×1024 pixels),which ensure comprehensive statistics.Microstructure information,such as three-dimensional density distribution and the frequency of the minimum spatial distance of inclusions on the sample surface of 150 mm^(2),were quantified by extracting the coordinates and sizes of individual features.A refined characterization method for two-dimensional structures and spatial information that is unattainable when performing manually or with software is provided.That will be useful for understanding properties or behaviors of weathering steel,and reducing the resort to physical testing.
文摘A series of NOAA AVHRR data over the East China Sea were collected from the ground station of the Second Institute of Oceanography, Hangzhou, China. Three methods, including a functional analytic method (FAM), a maximum cross correlation (MCC)'method and a correlation relaxation (C - R) method, are applied to derive the sea surface current field from sequential satellite images in the area of the East China Sea. Several preprocessing steps, such as geometric correction, SST determination, image projection, image navigation and grey value normalization as well as land and cloud mask are performed. The results from the three methods reflect the general current system in this area reasonably.
文摘To realize the high-precision vision measurement for large scale machine parts, a new vision measurement method based on dimension features of sequential partial images is proposed. Instead of mosaicking the partial images, extracting the dimension features of the sequential partial images and deriving the part size according to the relationships between the sequential images is a novel method to realize the high- precision and fast measurement of machine parts. To overcome the corresponding problems arising from the relative rotation between two sequential partial images, a rectifying method based on texture features is put forward to effectively improve the processing speed. Finally, a case study is provided to demonstrate the analysis procedure and the effectiveness of the proposed method. The experiments show that the relative error is less than 0. 012% using the sequential image measurement method to gauge large scale straight-edge parts. The measurement precision meets the needs of precise measurement for sheet metal parts.
基金Supported by National Basic Research Program of China (No.2003CB716103)partially supported by the US Army Breast Cancer Research Program (DAMD17-03-1-0446)
文摘The growth patterns of mammary fat pads and glandular tissues inside the fat pads may be related with the risk factors of breast cancer.Quantitative measurements of this relationship are available after segmentation of mammary pads and glandular tissues.Rat fat pads may lose continuity along image sequences or adjoin similar intensity areas like epidermis and subcutaneous regions.A new approach for automatic tracing and segmentation of fat pads in magnetic resonance imaging(MRI) image sequences is presented,which does not require that the number of pads be constant or the spatial location of pads be adjacent among image slices.First,each image is decomposed into cartoon image and texture image based on cartoon-texture model.They will be used as smooth image and feature image for segmentation and for targeting pad seeds,respectively.Then,two-phase direct energy segmentation based on Chan-Vese active contour model is applied to partitioning the cartoon image into a set of regions,from which the pad boundary is traced iteratively from the pad seed.A tracing algorithm based on scanning order is proposed to accurately trace the pad boundary,which effectively removes the epidermis attached to the pad without any post processing as well as solves the problem of over-segmentation of some small holes inside the pad.The experimental results demonstrate the utility of this approach in accurate delineation of various numbers of mammary pads from several sets of MRI images.
基金supported by the CONACYT/204212the DGEST of the Mexican Government under the PROMEP/107.5/10/5417
文摘This letter presents an autofocus （AF） method to position a high-magnification microscope lens that automatically captures hundreds of images from a single moving slide. These images are taken by a mobile clinic unit in a rural location, and are later automatically processed and revised by a remote specialist. This process requires high focus precision to enable image processing techniques to achieve proper results. Low focusing times are also required for the system to be operative. We propose a novel method that combines two focus measures with an adapted searching scheme to cope with both constraints.
基金supported by the National Natural Science Foundation of China (No. 60772124)the International Cooperation Project of Science and Technology Commission of Shanghai Municipality (No. 09530708700)the Shanghai University Innovation Funds for Graduates (Nos. SHUCX101060 and SHUCX102195)
文摘We propose a computational method for generating sequential kinoforms of real-existing full-color three- dimensional （3D） objects and realizing high-quality 3D imaging. The depth map and color information are obtained using non-contact full-color 3D measurement system based on binocular vision. The obtained full-color 3D data are decomposed into multiple slices with RGB channels. Sequential kinoforms of each channel are calculated and reconstructed using a Fresnel-diffraction-based algorithm called the dynamic- pseudorandom-phase tomographic computer holography （DPP-TCH）. Color dispersion introduced by different wavelengths is well compensated by zero-padding operation in the red and green channels of object slices. Numerical reconstruction results show that the speckle noise and color-dispersion are well suppressed and that high-quality full-color holographic 3D imaging is feasible. The method is useful for improving the 3D image quality in holographic displays with pixelated phase-type spatial light modulators （SLMs）.
