摘要:
This invention minimizes the color errors associated with performing conversion and/or correction of color digital image data using multi-dimensional look-up tables of a limited size. By distributing the errors across the color gamut it is possible to reduce the average color error as well as the maximum color errors associated with linear or conventional linear or nonlinear, e.g. cube-root or logarithmic, remapping schemes. The resulting advantage will be color images with greatly reduced artifacts.
摘要:
This invention provides a method for mapping an input color space to an output color space in such a way that the color reproduction characteristics of the saturated colors can be adjusted in a custom manner, while maintaining the desired tone reproduction on the neutral axis. This is accomplished by defining independently a tone transformation and a transformation for a plurality of highly saturated colors. A transformation is formed for the remaining color values having the specified transforms for the neutral and saturated colors as boundary values. In the preferred embodiment multi-dimensional look-up tables are used to implement the transform.
摘要:
A method for transforming input color values of a digital image to produce suitable output color values for use by a particular device is disclosed. In this method a plurality of color transforms are stored, each such transform responds to input color values of a digital image and produces output color values which can be used by the particular device. In the method an intermediate transform which is user desirable for transforming the input color values is formed by interpolating between the plurality of transforms.
摘要:
A method of making a thin lens having a desired high order curvature includes the steps of providing a layer of transparent photoresist; generating a continuous tone exposure pattern for exposing the photoresist such that when exposed and developed the layer of photoresist will possess the desired high order curvature; exposing the layer of photoresist; and developing the layer to produce the thin lens.
摘要:
A digital halftone image is produced by providing a binary bit image pattern having a minimum visual noise for each density level in the image, and the binary bit patterns being correlated in a manner that reduces visual noise resulting from transitions between patterns. The patterns are addressed by pixel density and x,y location to produce a halftone image. The patterns are generated by employing a stochastic minimization technique with a constraint to insure correlation between patterns.
摘要:
A method and apparatus for mapping a first color space into a second color space which allows a user to specify or constrain the mapping for a subset of the points within the first color space and determine the remaining unconstrained points according to a preexisting or default mapping.
摘要:
A digital halftone image is produced by providing a binary bit image pattern having a minimum visual noise for each density level in an image. The patterns are produced by employing a stochastic combinatorial minimization technique and a human visual system modulation transfer function (MTF) weighting function to generate a halftone pattern for each density level of the multi-level digital image signal. A halftone image is produced by modularly addressing these patterns with each pixel value in the image.
摘要:
A block adaptive differential pulse code modulation (DPCM) system includes both a lossless DPCM processor responsive to blocks of pixel values for producing encoder command signals and a lossy DPCM compressor responsive to blocks of pixel values for producing encoder command signals. An encoder receives the encoder command signals from the lossless DPCM processor and lossy DPCM compressor and produces a compressed encoded bit stream. A switch responsive to a compression configuration signal and to the encoder command signals from the lossy compressor selectively passes the encoder command signals from the lossless processor or the lossy compressor to the encoder.
摘要:
A convex interpolation apparatus and method to map source color signals in a n-dimensional color space to target color signals in a m-dimensional color space includes finding a set of sample signals in the source color space whose convex hull encloses the given signal; determining the coefficients needed to express the given signal as a convex combination of the set of sample signals; and interpolating the source signal to obtain a target signal in the target color space by using the coefficients and the sample signals is the target color space that correspond to the sample signals selected in the source color space. The sample signals in both color spaces can be lattice points or non-lattice points. A method and apparatus are also provided which can not only determine if a point is enclosed by a convex hull of a set of points in a n-dimensional space, but also simultaneously derive the coefficients needed to express the given point as a convex combination of the set of points.
摘要:
An efficient method for gamut clipping based on user-defined constraints on lightness and hue by: a) defining a color gamut surface of an output device using a gamut descriptor; b) specifying a search range based on maximum tolerances for lightness and hue changes; and, c) for each input color data point outside the gamut, mapping the data point to the closest point in a portion of the gamut surface specified by the search range.