Abstract: An embodiment of a method for reducing chroma noise in digital image data and of a corresponding image processor. Chrominance components are subjected to low-pass filtering. The strength of the low-pass filtering is modulated in accordance with the dynamic range of the luminance signal and the dynamic range of each of the two chrominance signals in order to avoid color bleeding at image-object edges. Moreover, the low-pass filtering is selectively applied to pixels with similar luminance and chrominance values only. A combination of down-sampling and up-sampling units is employed so that comparatively small filter kernels may be used for removing chroma noise with low spatial frequency.

Abstract: An image processing apparatus suitable for processing a digital image in YCrCb color space, the image having an initial luminance plane Y and two initial Cr, Cb chrominance planes, the processing apparatus including a first block that receives the initial luminance plane Y of the digital image and processes and modifies the initial luminance plane Y in order to provide a modified luminance plane Y in output; a color artifact correction block, operating in parallel with the first block, the correction block receiving the initial planes Y, Cr, Cb of the image and modifying the initial chrominance planes Cr and Cb through a pixel by pixel processing approach with a mobile working window, the correction block having a false colors correction sub-block and a purple fringing correction sub-block, or both, the sub-blocks structured to modify values of the initial Cr, Cb chrominance planes based on information contained in the initial Cr, Cb chrominance planes and also based on information contained in the initial lu

Abstract: An embodiment of a method for reducing chroma noise in digital image data and of a corresponding image processor. Chrominance components are subjected to low-pass filtering. The strength of the low-pass filtering is modulated in accordance with the dynamic range of the luminance signal and the dynamic range of each of the two chrominance signals in order to avoid color bleeding at image-object edges. Moreover, the low-pass filtering is selectively applied to pixels with similar luminance and chrominance values only. A combination of down-sampling and up-sampling units is employed so that comparatively small filter kernels may be used for removing chroma noise with low spatial frequency.

Abstract: A method calculates statistical parameters in function of stochastic momentums of the pixel intensities of a same primary color or complementary hue of a first working window (2k+1)×(2k+1), and of at least a second working window of smaller size, both centered on the pixel to be filtered and in choosing, as a function of the values of these statistical parameters, for each pixel of the color image to be filtered, the most appropriate filtering algorithm for enhancing as much as possible the contour sharpness and reducing noise and artifacts.

Abstract: An image processing apparatus suitable for processing a digital image in YCrCb color space, the image having an initial luminance plane Y and two initial Cr, Cb chrominance planes, the processing apparatus including a first block that receives the initial luminance plane Y of the digital image and processes and modifies the initial luminance plane Y in order to provide a modified luminance plane Y in output; a color artifact correction block, operating in parallel with the first block, the correction block receiving the initial planes Y, Cr, Cb of the image and modifying the initial chrominance planes Cr and Cb through a pixel by pixel processing approach with a mobile working window, the correction block having a false colors correction sub-block and a purple fringing correction sub-block, or both, the sub-blocks structured to modify values of the initial Cr, Cb chrominance planes based on information contained in the initial Cr, Cb chrominance planes and also based on information contained in the initial lu

Abstract: Color image signals, as derived, e.g., by interpolating the output from a color filter array are arranged in pixels, each pixel having associated detected color information for a first color as well as undetected filled-in color information for at least a second and a third color. The images are thus exposed to false color and zipper effect artifacts, and are subject to processing preferably including the steps of: checking the images for the presence of zipper effect artifacts, and i) if the checking reveals the presence of zipper effect artifacts, applying a zipper effect removal process to the image signals; ii) if the checking fails to reveal the presence of zipper effect artifacts, applying a false color removal process to the image signals. False color and zipper effect artifacts are thus preferably both reduced by adaptively using the zipper effect removal process and the false color removal process.

Abstract: A method calculates statistical parameters in function of stochastic momentums of the pixel intensities of a same primary color or complementary hue of a first working window (2k+1)×(2k+1), and of at least a second working window of smaller size, both centered on the pixel to be filtered and in choosing, as a function of the values of these statistical parameters, for each pixel of the color image to be filtered, the most appropriate filtering algorithm for enhancing as much as possible the contour sharpness and reducing noise and artifacts.

Abstract: Subdivision per basic color channels of grey level data generated by a color sensor is no longer required according to a novel color interpolation method of an image acquired by a digital color sensor generating grey levels for each image pixel as a function of the filter applied to the sensor by interpolating the values of missing colors of each image pixel for generating triplets or pairs of values of primary colors or complementary base hues for each image pixel. The method may include calculating spatial variation gradients of primary colors or complementary base hues for each image pixel and storing the information of directional variation of primary color or complementary base hue in look-up tables pertaining to each pixel.

Abstract: Color image signals, as derived, e.g., by interpolating the output from a color filter array are arranged in pixels, each pixel having associated detected color information for a first color as well as undetected filled-in color information for at least a second and a third color. The images are thus exposed to false color and zipper effect artifacts, and are subject to processing preferably including the steps of: checking the images for the presence of zipper effect artifacts, and i) if said checking reveals the presence of zipper effect artifacts, applying a zipper effect removal process to said image signals; ii) if said checking fails to reveal the presence of zipper effect artifacts, applying a false color removal process to said image signals. False color and zipper effect artifacts are thus preferably both reduced by adaptively using the zipper effect removal process and the false color removal process.

Abstract: Subdivision per basic color channels of grey level data generated by a color sensor is no longer required according to a novel color interpolation method of an image acquired by a digital color sensor generating grey levels for each image pixel as a function of the filter applied to the sensor by interpolating the values of missing colors of each image pixel for generating triplets or pairs of values of primary colors or complementary base hues for each image pixel. The method may include calculating spatial variation gradients of primary colors or complementary base hues for each image pixel and storing the information of directional variation of primary color or complementary base hue in look-up tables pertaining to each pixel.