2006 International Conference on Image Processing, 2006
Snakes, or active contours, have been widely used in image processing applications. Typical roadb... more Snakes, or active contours, have been widely used in image processing applications. Typical roadblocks to consistent performance include limited capture range, noise sensitivity, and poor convergence to concavities. This paper proposes a new design for the snake external force, called vector field convolution (VFC), to address these problems. Qualitative and quantitative comparisons with the gradient vector flow (GVF) external force are presented in this paper to show the advantages of this innovation.
Snakes, or active contours, have been widely used in image processing applications. Typical roadb... more Snakes, or active contours, have been widely used in image processing applications. Typical roadblocks to consistent performance include limited capture range, noise sensitivity, and poor convergence to concavities. This paper proposes a new external force for active contours, called vector field convolution (VFC), to address these problems. VFC is calculated by convolving the edge map generated from the image with the user-defined vector field kernel. We propose two structures for the magnitude function of the vector field kernel, and we provide an analytical method to estimate the parameter of the magnitude function. Mixed VFC is introduced to alleviate the possible leakage problem caused by choosing inappropriate parameters. We also demonstrate that the standard external force and the gradient vector flow (GVF) external force are special cases of VFC in certain scenarios. Examples and comparisons with GVF are presented in this paper to show the advantages of this innovation, including superior noise robustness, reduced computational cost, and the flexibility of tailoring the force field.
Newly isolated serotypes of AAV readily cross the endothelial barrier to provide efficient transg... more Newly isolated serotypes of AAV readily cross the endothelial barrier to provide efficient transgene delivery throughout the body. However, tissue-specific expression is preferred in most experimental studies and gene therapy protocols. Previous efforts to restrict gene expression to the myocardium often relied on direct injection into heart muscle or intracoronary perfusion. Here, we report an AAV vector system employing the cardiac troponin T (cTnT) promoter. Using luciferase and enhanced green fluorescence protein (eGFP), the efficiency and specificity of cardiac reporter gene expression using AAV serotype capsids: AAV-1, 2, 6, 8 or 9 were tested after systemic administration to 1-week-old mice. Luciferase assays showed that the cTnT promoter worked in combination with each of the AAV serotype capsids to provide cardiomyocyte-specific gene expression, but AAV-9 followed closely by AAV-8 was the most efficient. AAV9-mediated gene expression from the cTnT promoter was 640-fold greater in the heart compared with the next highest tissue (liver). eGFP fluorescence indicated a transduction efficiency of 96% using AAV-9 at a dose of only 3.15Â10 10 viral particles per mouse. Moreover, the intensity of cardiomyocyte eGFP fluorescence measured on a cell-by-cell basis revealed that AAV-mediated gene expression in the heart can be modeled as a Poisson distribution, requiring an average of nearly two vector genomes per cell to attain an 85% transduction efficiency.
Proceedings of 1st International Conference on Image Processing, 2000
We introduce the Anisotropic Diffusion Pyramid (ADP), a structure for multiresolution image proce... more We introduce the Anisotropic Diffusion Pyramid (ADP), a structure for multiresolution image processing. We also develop the ADP for use in region-based segmentation. The pyramid is constructed using the anisotropic diffusion equations, creating an efficient scale-space representation. Segmentation is accomplished using pyramid node linking. Since anisotropic diffusion preserves edge localization as the scale is increased, the region boundaries in the
Most of the existing watermarking processes becomevulnerable when the attacker knows the watermar... more Most of the existing watermarking processes becomevulnerable when the attacker knows the watermark insertionalgorithm. This paper presents an invisible spatial domain watermarkinsertion algorithm for which we show that the watermarkcan be recovered, ...
2004 International Conference on Image Processing, 2004. ICIP '04., 2004
Ankle cartilage surface segmentation is a prestep to compute the cartilage thickness which is use... more Ankle cartilage surface segmentation is a prestep to compute the cartilage thickness which is used to evaluate the treatment of ankle joint diseases. Because of the un-ideal imaging condition, the acquired ankle images are often noised and the cartilage parts in the images are often disconnected, thus traditional techniques such as gradient-based edge detection are not suitable for the segmentation
2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, 2007
Page 1. QUANTIFICATION OF CARDIAC DYSSYNCHRONY IN MICE AFTER MYOCARDIAL INFARCTION USING HIGH RES... more Page 1. QUANTIFICATION OF CARDIAC DYSSYNCHRONY IN MICE AFTER MYOCARDIAL INFARCTION USING HIGH RESOLUTION ULTRASOUND Yinbo Li, Christopher D. Garson, Yaqin Xu, Scott T. Acton*, Brent A. French and John A. Hossack ...
2006 International Conference on Image Processing, 2006
Cardiac parameters such as end-systolic volume, ejection fraction and myocardial mass are essenti... more Cardiac parameters such as end-systolic volume, ejection fraction and myocardial mass are essential to the diagnosis and treatment of cardiovascular disease (CVD). Traditionally, these parameters are calculated based on manual myocardial segmentation by a trained technician. Fast, accurate, and automatic segmentation would provide researchers with an increased subject pool, an enhanced understanding of CVD, and may lead to the development of new therapies. In this paper we propose an automated algorithm for myocardial segmentation. This method utilizes speckle reducing anisotropic diffusion to assist the automated contour initialization. Speckle tracking segmentation (STS) is then applied throughout the cardiac cycle to track the myocardial borders. This approach, compared to standard active contour techniques, reduces the RMSE to ground truth by an order of magnitude.
In area morphology, the area open±close (AOC) and close±open (ACO) operations are based on ®lteri... more In area morphology, the area open±close (AOC) and close±open (ACO) operations are based on ®ltering the connected components in the image level sets. Unlike traditional morphology that enforces the shape of the structuring element on image region boundaries, area morphology allows removal of small features without boundary distortion. This study de®nes ascending and descending objects that depend on the area of the connected components of the level sets. The major contribution of the paper is to de®ne image edges at the boundaries of the ascending and descending objects. From this area morphology approach, thin, closed contours are provided that are suitable for use in image segmentation. A notable strength of the area morphology edge detector is that it does not require the use of a threshold. The edge maps are Euclidean invariant and causal, and yield good performance in terms of edge localization and the suppression of below-scale detail. The results demonstrate the superior performance of the area operator-based edge detection over the conventional techniques.
2006 Fortieth Asilomar Conference on Signals, Systems and Computers, 2006
We propose a constrained active surface model, called the rigid body surface, that deforms via ri... more We propose a constrained active surface model, called the rigid body surface, that deforms via rigid body transformation. In each iteration, the surface is deformed first via partial differential equations and then the least-squares estimate of the rigid body transformation between the deformed surface and predefined surface is calculated. The rigid body transformation estimate is based upon the singular value
2006 International Conference on Image Processing, 2006
Snakes, or active contours, have been widely used in image processing applications. Typical roadb... more Snakes, or active contours, have been widely used in image processing applications. Typical roadblocks to consistent performance include limited capture range, noise sensitivity, and poor convergence to concavities. This paper proposes a new design for the snake external force, called vector field convolution (VFC), to address these problems. Qualitative and quantitative comparisons with the gradient vector flow (GVF) external force are presented in this paper to show the advantages of this innovation.
Snakes, or active contours, have been widely used in image processing applications. Typical roadb... more Snakes, or active contours, have been widely used in image processing applications. Typical roadblocks to consistent performance include limited capture range, noise sensitivity, and poor convergence to concavities. This paper proposes a new external force for active contours, called vector field convolution (VFC), to address these problems. VFC is calculated by convolving the edge map generated from the image with the user-defined vector field kernel. We propose two structures for the magnitude function of the vector field kernel, and we provide an analytical method to estimate the parameter of the magnitude function. Mixed VFC is introduced to alleviate the possible leakage problem caused by choosing inappropriate parameters. We also demonstrate that the standard external force and the gradient vector flow (GVF) external force are special cases of VFC in certain scenarios. Examples and comparisons with GVF are presented in this paper to show the advantages of this innovation, including superior noise robustness, reduced computational cost, and the flexibility of tailoring the force field.
Newly isolated serotypes of AAV readily cross the endothelial barrier to provide efficient transg... more Newly isolated serotypes of AAV readily cross the endothelial barrier to provide efficient transgene delivery throughout the body. However, tissue-specific expression is preferred in most experimental studies and gene therapy protocols. Previous efforts to restrict gene expression to the myocardium often relied on direct injection into heart muscle or intracoronary perfusion. Here, we report an AAV vector system employing the cardiac troponin T (cTnT) promoter. Using luciferase and enhanced green fluorescence protein (eGFP), the efficiency and specificity of cardiac reporter gene expression using AAV serotype capsids: AAV-1, 2, 6, 8 or 9 were tested after systemic administration to 1-week-old mice. Luciferase assays showed that the cTnT promoter worked in combination with each of the AAV serotype capsids to provide cardiomyocyte-specific gene expression, but AAV-9 followed closely by AAV-8 was the most efficient. AAV9-mediated gene expression from the cTnT promoter was 640-fold greater in the heart compared with the next highest tissue (liver). eGFP fluorescence indicated a transduction efficiency of 96% using AAV-9 at a dose of only 3.15Â10 10 viral particles per mouse. Moreover, the intensity of cardiomyocyte eGFP fluorescence measured on a cell-by-cell basis revealed that AAV-mediated gene expression in the heart can be modeled as a Poisson distribution, requiring an average of nearly two vector genomes per cell to attain an 85% transduction efficiency.
Proceedings of 1st International Conference on Image Processing, 2000
We introduce the Anisotropic Diffusion Pyramid (ADP), a structure for multiresolution image proce... more We introduce the Anisotropic Diffusion Pyramid (ADP), a structure for multiresolution image processing. We also develop the ADP for use in region-based segmentation. The pyramid is constructed using the anisotropic diffusion equations, creating an efficient scale-space representation. Segmentation is accomplished using pyramid node linking. Since anisotropic diffusion preserves edge localization as the scale is increased, the region boundaries in the
Most of the existing watermarking processes becomevulnerable when the attacker knows the watermar... more Most of the existing watermarking processes becomevulnerable when the attacker knows the watermark insertionalgorithm. This paper presents an invisible spatial domain watermarkinsertion algorithm for which we show that the watermarkcan be recovered, ...
2004 International Conference on Image Processing, 2004. ICIP '04., 2004
Ankle cartilage surface segmentation is a prestep to compute the cartilage thickness which is use... more Ankle cartilage surface segmentation is a prestep to compute the cartilage thickness which is used to evaluate the treatment of ankle joint diseases. Because of the un-ideal imaging condition, the acquired ankle images are often noised and the cartilage parts in the images are often disconnected, thus traditional techniques such as gradient-based edge detection are not suitable for the segmentation
2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, 2007
Page 1. QUANTIFICATION OF CARDIAC DYSSYNCHRONY IN MICE AFTER MYOCARDIAL INFARCTION USING HIGH RES... more Page 1. QUANTIFICATION OF CARDIAC DYSSYNCHRONY IN MICE AFTER MYOCARDIAL INFARCTION USING HIGH RESOLUTION ULTRASOUND Yinbo Li, Christopher D. Garson, Yaqin Xu, Scott T. Acton*, Brent A. French and John A. Hossack ...
2006 International Conference on Image Processing, 2006
Cardiac parameters such as end-systolic volume, ejection fraction and myocardial mass are essenti... more Cardiac parameters such as end-systolic volume, ejection fraction and myocardial mass are essential to the diagnosis and treatment of cardiovascular disease (CVD). Traditionally, these parameters are calculated based on manual myocardial segmentation by a trained technician. Fast, accurate, and automatic segmentation would provide researchers with an increased subject pool, an enhanced understanding of CVD, and may lead to the development of new therapies. In this paper we propose an automated algorithm for myocardial segmentation. This method utilizes speckle reducing anisotropic diffusion to assist the automated contour initialization. Speckle tracking segmentation (STS) is then applied throughout the cardiac cycle to track the myocardial borders. This approach, compared to standard active contour techniques, reduces the RMSE to ground truth by an order of magnitude.
In area morphology, the area open±close (AOC) and close±open (ACO) operations are based on ®lteri... more In area morphology, the area open±close (AOC) and close±open (ACO) operations are based on ®ltering the connected components in the image level sets. Unlike traditional morphology that enforces the shape of the structuring element on image region boundaries, area morphology allows removal of small features without boundary distortion. This study de®nes ascending and descending objects that depend on the area of the connected components of the level sets. The major contribution of the paper is to de®ne image edges at the boundaries of the ascending and descending objects. From this area morphology approach, thin, closed contours are provided that are suitable for use in image segmentation. A notable strength of the area morphology edge detector is that it does not require the use of a threshold. The edge maps are Euclidean invariant and causal, and yield good performance in terms of edge localization and the suppression of below-scale detail. The results demonstrate the superior performance of the area operator-based edge detection over the conventional techniques.
2006 Fortieth Asilomar Conference on Signals, Systems and Computers, 2006
We propose a constrained active surface model, called the rigid body surface, that deforms via ri... more We propose a constrained active surface model, called the rigid body surface, that deforms via rigid body transformation. In each iteration, the surface is deformed first via partial differential equations and then the least-squares estimate of the rigid body transformation between the deformed surface and predefined surface is calculated. The rigid body transformation estimate is based upon the singular value
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Papers by Scott Acton