Abstract: Methods and apparatus are provided for electronically trapping a selected digital color image pixel. A plurality of pixels that surround the selected pixel are identified, a colorant value of each of the surrounding pixels is compared with a corresponding colorant value of the selected pixel, one of the surrounding pixels is identified to control trapping of the selected pixel, and the selected pixel is trapped based on a relationship between a colorant value of the selected pixel and a corresponding colorant value of the identified controlling pixel.

Abstract: Methods and apparatus are provided for electronically trapping a selected digital color image pixel. A plurality of pixels that surround the selected pixel are identified, a colorant value of each of the surrounding pixels is compared with a corresponding colorant value of the selected pixel, one of the surrounding pixels is identified to control trapping of the selected pixel, and the selected pixel is trapped based on a relationship between a colorant value of the selected pixel and a corresponding colorant value of the identified controlling pixel.

Abstract: From a raster page, patches of connected pixels of the same color are identified. Patches of at least a predetermined sized, typically corresponding to text or line art objects, are subjected to a lossless compression. Patches below the predetermined size, typically corresponding to image or photo objects, are substantially subjected to a lossy compression. The patch predetermined size controls the mix of lossless and lossy compression procedures. Optimum compression is achieved by maximizing the lossless compression while attaining a targeted compression ratio. Various features include efficient recognition and encoding of patches, refined treatment of the boundaries between the lossless- and the lossy-compressed pixels, adaptive compression ratio control, and fail-safe compression provisions.

Abstract: From a raster page, patches of connected pixels of the same color are identified. Patches of at least a predetermined sized, typically corresponding to text or line art objects, are subjected to a lossless compression. Patches below the predetermined size, typically corresponding to image or photo objects, are substantially subjected to a lossy compression. The patch predetermined size controls the mix of lossless and lossy compression procedures. Optimum compression is achieved by maximizing the lossless compression while attaining a targeted compression ratio. Various features include efficient recognition and encoding of patches, refined treatment of the boundaries between the lossless- and the lossy-compressed pixels, adaptive compression ratio control, and fail-safe compression provisions.

Abstract: An apparatus and method for providing bit-rate reduction and reconstruction of image data. Bit-rate reduction of 32-bit CMYK combinations into 16-bit code words is performed on a pixel by pixel basis by stepwise calculations or by using LUTs. Bit-rate reduction takes place during PostScript.RTM. interpretation where the output image pixels are generated in a possibly arbitrary order. Bit expansion from 16-bit code words to 32-bit data for 8 bits per component of the CMYK image values is performed while real time printing, preferably by direct table look up. During bit-rate reduction, the image data may be non-linearly corrected to compensate for perceptual non-uniformities and for non-linearities in the input/output relationship of the reproduction device. Quantization and coding may be accomplished by thresholding the non-linearly corrected image data by values from a dither array.

Abstract: The present invention is a method for calibrating color reproduction devices such as printers and for stabilizing the print colors generated by a computer controlled color reproduction device. Further, the present invention acts to standardize the print colors produced across a family or series of color reproduction devices. It may be incorporated into a color management system used to produce consistent colors across a variety of reproduction devices. In the first embodiment of the present invention, an object scanning device and an object color reproduction device are used. In the second embodiment, an object densitometer is used as the measuring device to measure densities. In yet another embodiment, an object colorimeter is used as the measuring device to measure CIE values. The present invention enables generation of a set of calibration curves for correcting the color output of the color reproduction device.

Abstract: A color separation scanner comprising a movable support arranged for mounting thereon of a two-dimensional input picture to be scanned and color separation sensing apparatus arranged for sensing the two-dimensional input picture for providing electrical signals representing color separations of the two-dimensional picture, the color separation sensing apparatus including a scanning head having a plurality of generally parallel CCD arrays, associated with dichroic filter means and operative for simultaneous scanning of the two-dimensional input picture.