Enhancement of video images by selective introduction of gray-scale pels
First Claim
1. In a system for receiving and storing non-coded binary image pel data and for generating an image derived from the stored data on a gray scale display device, a method for enhancing the visual quality of the displayed image characterized by the steps of:
- examining the stored data on a pel by pel basis along successive pel lines to identify unit steps in binary pel values in a direction transverse to the direction of the successive lines;
modifying the stored data by assigning gray scale values to a limited number of pels on opposite sides of each identified unit step to create a string of gradually changing pel values extending through each identified unit step;
assigning fixed gray scale values to any pels not already modified to establish upper and lower limits on gray scale pel values; and
generating the displayed image in accordance with the assigned gray scale pel values.
1 Assignment
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Accused Products
Abstract
A technique for enhancing a displayed image originally stored at a density of 1 data bit per pel. The stored data is scanned to locate unit steps, one-row or one-column steps in binary values. Whenever a unit step is found, the distance from the step to the nearest transitions on both sides of the step are found. The distances are used to access lookup tables which assign 4 bit gray scale values to limited numbers of pels on both sides of the unit step. The assigned gray scale values produce a gradually-darkening string of pels extending through the step. When the entire image field has been scanned, a maximum 4 bit pel value is assigned to any unmodified pel having an original binary value of 1 and a minimum pel value is assigned to any unmodified pel having an original binary value of 0. The visual quality of the displayed image is enhanced by the selective introduction of intermediate gray scale values for pels adjacent unit steps.
91 Citations
8 Claims
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1. In a system for receiving and storing non-coded binary image pel data and for generating an image derived from the stored data on a gray scale display device, a method for enhancing the visual quality of the displayed image characterized by the steps of:
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examining the stored data on a pel by pel basis along successive pel lines to identify unit steps in binary pel values in a direction transverse to the direction of the successive lines; modifying the stored data by assigning gray scale values to a limited number of pels on opposite sides of each identified unit step to create a string of gradually changing pel values extending through each identified unit step; assigning fixed gray scale values to any pels not already modified to establish upper and lower limits on gray scale pel values; and generating the displayed image in accordance with the assigned gray scale pel values. - View Dependent Claims (2, 3)
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4. In a system for receiving and storing binary data representative of pels in a previously captured image wherein the binary data is stored in a memory array, arranged in logical rows and logical columns, at a density of one bit per pel, a method of assigning gray scale values to certain pels to enhance the visual quality of the image when displayed on a gray scale display device, said method characterized by the steps of:
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examining the stored binary data on a pel by pel basis along successive pel lines to identify unit steps in binary pel values in a direction transverse to the direction of the successive lines, each identified unit step being adjacent a pel arbitrarily defined as occurring at an intersection of row J and column I in a display area; examining the binary data beginning at column I+1 and continuing to the right until a display boundary is encountered or a change in binary data is found in row J or in one of rows J-1 and J+1 to derive a pel distance RD; examining the binary data beginning at column I and continuing to the left until a display boundary is encountered or a change in binary data is found in row J or one of rows J-1 and J+1 to derive a pel distance LD; modifying the stored data representing pels to the right of the unit step by assigning gray scale values as a function of the derived distance RD; modifying the stored data representing pels to the right of the unit step by assigning gray scale values as a function of the derived distance RD; modifying the stored data representing pels to the left of the unit step by assigning gray scale values as a function of the derived distance LD; assigning fixed gray scale values to any pels remaining unchanged following the modifying steps to fix upper and lower limits on gray scale pel values; and generating the displayed image in accordance with the assigned gray scale pel values. - View Dependent Claims (5, 6, 7)
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8. A system for enhancing the visual quality of a gray scale image produced by a gray scale display device where the image is derived from data stored at a density of one bit per pel, said system including:
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means for examining the stored data to locate unit steps in binary pel values; means for assigning gray scale values to pels on opposite sides of each unit step to create a string of gradually changing pel values extending through each identified unit step; means for assigning fixed gray scale values to any pels not already modified to establish limiting black/white pel values; and means for generating the displayed image in accordance with the assigned gray scale pel values.
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Specification