Showing papers on "Color gradient published in 2002"
Patent•
2 Oct 2002TL;DR: In this paper, a trap generator is used to provide a trap color given two input colors, such that the color of the trap zone is nearly imperceptible in the presence of the two initial colors.
Abstract: A method of correction for toner misregistration in color printing systems, specifically for run length encoded image data. This method, called “trapping”, usually involves extending the color separations one or more pixels to overlay the edge. The color of the “trap zone” is chosen such that it is nearly imperceptible in the presence of the two initial colors. Our approach assumes the existence of a “trap generator”, which provides a trap color given two input colors. In run length encoded image format, the image is comprised of an array of “scanlines”, consisting of a string of “runs” that are specified by a minimum position in the fast (horizontal) direction, a length, and a color. We describe a method of trapping involving the following steps: 1) inspecting the run lengths in each scanline to determine the color edges of the image; 2) sending the colors at the boundaries to the trap generator to determine the trap color; and 3) modifying the intersecting runs with the trap color. The result is an efficient elimination of the edge defects at color boundaries, which is enabled by the run length encoded image format.
21 citations
24 Jun 2002
TL;DR: A novel merged-color histogram (MCH) method for color image retrieval is proposed to facilitate matching between similar colors by means of color quantization and palette merging.
Abstract: Conventional histogram-based image retrieval algorithms usually find only intersecting areas of the color-component distributions of images, and thus work well in matching images with exact colors instead of similar colors, especially for computer generated pictures. This could be greatly affected by overall variations, such as intensity changes. A novel merged-color histogram (MCH) method for color image retrieval is proposed to facilitate matching between similar colors by means of color quantization and palette merging. Color quantization compacts the color information and matches each color instead of color components, and matching of similar colors is accomplished using palette merging. Experimental results show that the proposed MCH method is about 11-32% more precise in the first 20 retrievals for the same image query, and is able to recall 14%-23% more relevant images in the first 100 retrievals, as compared to the conventional RGB-based histogram method.
21 citations
TL;DR: The proposed color map maintains an aesthetically pleasing color image that automatically reproduces to a monotonic grayscale with discrete, quantifiable saturation levels.
Abstract: Default color maps on color images often reproduce to confusing grayscale images. The proposed color map maintains an aesthetically pleasing color image that automatically reproduces to a monotonic grayscale with discrete, quantifiable saturation levels.
17 citations
11 Aug 2002
TL;DR: A combination of a skin chrominance-based image segmentation with a color vector gradient-based edge detection and a novel approach to hand posture recognition based on phase-only correlation are applied to classify a subset of static hand postures of the Japanese sign language.
Abstract: A system for the detection of human faces and for the classification of hand postures in color images is presented. We first propose to apply a combination of a skin chrominance-based image segmentation with a color vector gradient-based edge detection to efficiently detect faces and hands. A statistical model for face detection based on invariant moments is then used to discriminate between faces and hands in the segmented images. A novel approach to hand posture recognition based on phase-only correlation is finally applied to classify a subset of static hand postures of the Japanese sign language, each posture representing a given phoneme, and also to discriminate between hand postures and the image scene background. Experiments show that the additional use of the color gradient significantly improves the correct rate of face detection, and that the phase-only correlation filter yields a high rate of discrimination between different static hand postures as well as between hand postures and the scene background.
13 citations
Patent•
28 Oct 2002
TL;DR: In this article, a method and apparatus for image compression in block units, and particularly to the image editor, color equalizer and error diffuser functions thereof, is presented, where processing is done in blocks of 4×4 pixels.
Abstract: The present invention relates to a method and apparatus for image compression in block units, and particularly to the image editor, color equalizer and error diffuser functions thereof. According to this image compression method, processing is done in blocks of 4×4 pixels. In each block, two representative colors and two interpolated colors that are gained by linear interpolation between the two representative colors, i.e., four colors in total, are used. One of these four colors is allotted to each pixel. The image editor function directly edits the reference relationship between the representative color and the color of the pixels. The color equalizer function performs encoding by taking differences in coloring between a TV and a PC monitor in consideration, thereby reproducing images similar to colors seen by the PC user on the TV of a game machine. The error diffuser function produces a pseudo realization of colors that do not correspond to the representative and interpolated colors by mixing different colors in pixel units.
8 citations
Patent•
24 Jun 2002TL;DR: In this paper, the set of palette colors is determined based on the distribution of colors in the input digital image supplemented by a distribution of important colors, where the number of palette colours is less than the possible input colors.
Abstract: Disclosed is a method for converting an input digital color image having a set of possible input colors to an output digital color image having a set of palette colors, the number of palette colors being less than the number of possible input colors, wherein the set of palette colors is determined based on the distribution of colors in the input digital image supplemented by a distribution of important colors.
4 citations
1 May 2002
TL;DR: In this paper, the visibility threshold of a color gradient across the screen is determined for specific application of mobile displays using a double-stimulus subjective test, where each pair of stimuli is shown twice to the subjects: once with the two stimuli of the pair simultaneously, and once with two stimuli from the pair time-sequentially.
Abstract: The visibility threshold of a color gradient across the screen is determined for the specific application of mobile displays. The color gradient was implemented as a change in saturation or in hue from the center of the screen towards the edges in horizontal direction. Its visibility threshold is determined in a double-stimulus subjective test. To investigate the influence of the way stimuli are presented in this type of tests, each pair of stimuli is shown twice to the subjects: once with the two stimuli of the pair simultaneously, and once with the two stimuli of the pair time-sequentially. The results exhibit a remarkable difference in the effect of the way stimuli are presented between the visibility in a saturation gradient and in a hue gradient.
2 citations
16 Dec 2002
TL;DR: This paper shall propose a new scheme that incorporates both CIQBM and Partial LBG that can dynamically adjust the number of colors needed according to the content of the image; in other words, without damaging the image quality, this new scheme will use as few colors as possible to present the color image.
Abstract: The Indexed color mode is used mainly in order to lower the number of colors and thus the need for memory space. When the RGB mode is used to describe pixel values, there are totally 16,777,216 colors for each color image; however, an ordinary color image usually does not need so many colors. Generally, 256 colors are enough for common color images; that is, it is usually more than adequate to select 256 representative colors according to the content of the image. However, some images can be so simple in color structure that not so many as 256 colors (e.g. 128 colors, 64 colors) are necessary. In this paper, we shall propose a new scheme that incorporates both CIQBM and Partial LBG. Our new scheme can dynamically adjust the number of colors needed according to the content of the image; in other words, without damaging the image quality, our new scheme will use as few colors as possible to present the color image. As a result, it will reduce the storage demand and save transmission time for images over networks.
2 citations