An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now axe widely used in ...An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now axe widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearance models. When the predictive results are evaluated, for forward model, the output color appearance space is converted to the uniform color space based on CAM and is evaluated, while for reverse model, because the prediction precision is insufficient, we try to convert the color appearance space, which is the cylinder space, to the cube space similar to the red, green, and blue (RGB) space, and the results show that the precision is obviously improved.展开更多
A psychophysical experiment under constant stimuli is conducted on a CRT display to measure the visual suprathreshold color differences for five color centers recommended by CIE under the same five background colors.T...A psychophysical experiment under constant stimuli is conducted on a CRT display to measure the visual suprathreshold color differences for five color centers recommended by CIE under the same five background colors.The performances of four CIELAB-based,three CIECAM02-based,and two OSA-UCS-based formulas are tested.Detailed analysis results indicate the existence of chromatic crispening effect.CIEDE2000 performs best for the gray center and gray background,whereas CAM02-LCD and CAM02-UCS have the best performance for non-neutral backgrounds.CAM02-LCD significantly outperforms all other formulas for all color centers under all background colors.展开更多
According to the color constancy theory, a modified variation Retinex is proposed for improving the visibility of the dark regions in images under insufficient and/or non-uniform lighting conditions. A new penalty fun...According to the color constancy theory, a modified variation Retinex is proposed for improving the visibility of the dark regions in images under insufficient and/or non-uniform lighting conditions. A new penalty functional based on nonlinear diffusion and correlation between the reflectance and the given image is designed for the intensity image enhancement, followed by adaptive color compensation. With high computational efficiency achieved by an improved multi-resolution algorithm, simulation results prove that the proposed method shows more colorful and vivid visual performance, and achieves wider dynamic range with higher objective standard values.展开更多
文摘An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now axe widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearance models. When the predictive results are evaluated, for forward model, the output color appearance space is converted to the uniform color space based on CAM and is evaluated, while for reverse model, because the prediction precision is insufficient, we try to convert the color appearance space, which is the cylinder space, to the cube space similar to the red, green, and blue (RGB) space, and the results show that the precision is obviously improved.
文摘A psychophysical experiment under constant stimuli is conducted on a CRT display to measure the visual suprathreshold color differences for five color centers recommended by CIE under the same five background colors.The performances of four CIELAB-based,three CIECAM02-based,and two OSA-UCS-based formulas are tested.Detailed analysis results indicate the existence of chromatic crispening effect.CIEDE2000 performs best for the gray center and gray background,whereas CAM02-LCD and CAM02-UCS have the best performance for non-neutral backgrounds.CAM02-LCD significantly outperforms all other formulas for all color centers under all background colors.
基金supported by the National "863" Project of China under Grant No.2007AA701121the NDS&T's Key Laboratory Foundation under Grant No.X80c6106.
文摘According to the color constancy theory, a modified variation Retinex is proposed for improving the visibility of the dark regions in images under insufficient and/or non-uniform lighting conditions. A new penalty functional based on nonlinear diffusion and correlation between the reflectance and the given image is designed for the intensity image enhancement, followed by adaptive color compensation. With high computational efficiency achieved by an improved multi-resolution algorithm, simulation results prove that the proposed method shows more colorful and vivid visual performance, and achieves wider dynamic range with higher objective standard values.
