AIM To use a computerized shape-from-shading technique to characterize the topography of the small intestinal mucosa.METHODS Videoclips comprised of 100-200 images each were obtained from the distal duodenum in 8 celi...AIM To use a computerized shape-from-shading technique to characterize the topography of the small intestinal mucosa.METHODS Videoclips comprised of 100-200 images each were obtained from the distal duodenum in 8 celiac and 8 control patients.Images with high texture were selected from each videoclip and projected from two to three dimensions by using grayscale pixel brightness as the Z-axis spatial variable.The resulting images for celiac patients were then ordered using the Marsh score to estimate the degree of villous atrophy,and compared with control data.RESULTS Topographic changes in celiac patient three-dimensional constructs were often more variable as compared to controls.The mean absolute derivative in elevation was 2.34 ± 0.35 brightness units for celiacs vs 1.95 ± 0.28 for controls(P = 0.014).The standard deviation of the derivative in elevation was 4.87 ± 0.35 brightness units for celiacs vs 4.47 ± 0.36 for controls(P = 0.023).Celiac patients with Marsh ⅢC villous atrophy tended to have the largest topographic changes.Plotted in two dimensions,celiac data could be separated from controls with 80% sensitivity and specificity.CONCLUSION Use of shape-from-shading to construct three-dimensional projections approximating the actual spatial geometry of the small intestinal substrate is useful to observe features not readily apparent in two-dimensional videocapsule images.This method represents a potentially helpful adjunct to detect areas of pathology during videocapsule analysis.展开更多
This paper translates the recognifion of curvatare radius in robot moving in bent pipe into an issue of shape-from-shading, and introduces genetic algorithms into the optimizaton process to improve the efficiency of o...This paper translates the recognifion of curvatare radius in robot moving in bent pipe into an issue of shape-from-shading, and introduces genetic algorithms into the optimizaton process to improve the efficiency of optimization.Experiments prove that thes method can satisfy the autonomous control requrement for robot moving in bent pipe in both speed and accuray.展开更多
文摘AIM To use a computerized shape-from-shading technique to characterize the topography of the small intestinal mucosa.METHODS Videoclips comprised of 100-200 images each were obtained from the distal duodenum in 8 celiac and 8 control patients.Images with high texture were selected from each videoclip and projected from two to three dimensions by using grayscale pixel brightness as the Z-axis spatial variable.The resulting images for celiac patients were then ordered using the Marsh score to estimate the degree of villous atrophy,and compared with control data.RESULTS Topographic changes in celiac patient three-dimensional constructs were often more variable as compared to controls.The mean absolute derivative in elevation was 2.34 ± 0.35 brightness units for celiacs vs 1.95 ± 0.28 for controls(P = 0.014).The standard deviation of the derivative in elevation was 4.87 ± 0.35 brightness units for celiacs vs 4.47 ± 0.36 for controls(P = 0.023).Celiac patients with Marsh ⅢC villous atrophy tended to have the largest topographic changes.Plotted in two dimensions,celiac data could be separated from controls with 80% sensitivity and specificity.CONCLUSION Use of shape-from-shading to construct three-dimensional projections approximating the actual spatial geometry of the small intestinal substrate is useful to observe features not readily apparent in two-dimensional videocapsule images.This method represents a potentially helpful adjunct to detect areas of pathology during videocapsule analysis.
文摘This paper translates the recognifion of curvatare radius in robot moving in bent pipe into an issue of shape-from-shading, and introduces genetic algorithms into the optimizaton process to improve the efficiency of optimization.Experiments prove that thes method can satisfy the autonomous control requrement for robot moving in bent pipe in both speed and accuray.
