초록 ▼

A scheme for compressing and reconstructing multi-color high resolution navigation image data, such as aeronautical chart images provides an effective bit rate of one bit per pixel. Data representative of the image of a color aeronautical chart is sampled for a plurality of aerial grid points of the

A scheme for compressing and reconstructing multi-color high resolution navigation image data, such as aeronautical chart images provides an effective bit rate of one bit per pixel. Data representative of the image of a color aeronautical chart is sampled for a plurality of aerial grid points of the image (corresponding to pixels of the displays) each sample being digitized to provide an original color-representative matrix of data points, each resolved to some number of digital bits per basic color, per sample point. The color data is transformed into data representative of luminance (Y) and in-phase and guadrature chrominance (I, Q) components thereof. The Y, I, Q values are compressed using a clustering process that produces, for an aeronautical chart, sixteen clusters of combinations of colors and shades in the Y, I, Q domain. Then, for each sample point, a four bit code representative of the centroid of the three dimensional (Y, I, Q) cluster in which its transformed color/shade value is located is generated, resulting in a preliminary bit rate of six-to-one (four bits per pixel). This preliminarily compressed color image data is further processed using a four-to-one compression code-table to obtain the desired one-bit/pixel bit rate.

대표청구항 ▼

A method of compressing the effective bandwidth of digitally encoded signals representative of the color composition of picture elements that make up a multiple color image pattern comprising steps of: (a) transforming the color composition of each picture element into its luminance and in-phase and

A method of compressing the effective bandwidth of digitally encoded signals representative of the color composition of picture elements that make up a multiple color image pattern comprising steps of: (a) transforming the color composition of each picture element into its luminance and in-phase and quadrature chrominance components; (b) generating a histogram of the luminance and chrominance components obtained in step (a) for the picture elements of said image pattern, said histogram being formed of a plurality of clusters of said luminance and chrominance components; (c) for each cluster of which said histogram generated in step (b) is formed, generating a respective first digital code representative thereof; (d) for each picture element, generating a second digital code, corresponding to that first digital code which is representative of the cluster to which the luminance and chrominance components of said each picture element is closest; and (e) for each of respective pluralities of said second digital codes associated with prescribed pluralities of neighboring picture elements of said multiple color image pattern, generating a third digital code representative of a prescribed combination of colors of which a respective one of said prescribed pluralities of neighboring picture elements within said multiple color image pattern may be formed.