Edge detection method and apparatus for an image processing system
First Claim
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1. An edge detection method comprising:
- a converting step comprising steps for obtaining a mean value Mi of pixel data Z;
in an n×
n window and converting said pixel data in said n×
n window into tri-state values Vj using said mean value Mi and a predetermined threshold value e ##EQU14## for j=1, 2 . . . , r;
a comparing step for comparing Vj, which is said pixel data represented in tri-state values, with four pre-specified edge patterns W1, W2, W3 and W4, where ##EQU15## where the superscript T represents the transpose of the matrix; and
decision steps for determining said pixel data to be an edge if Vj is equal to any one of said four pre-specified edge patterns, and otherwise not to be an edge.
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Abstract
An edge detection apparatus and method for an image processing system are disclosed. The apparatus comprises a conversion means for converting input pixel data into tri-state valves, a matching means for obtaining inner products of tri-state valves and prespecified edge patterns and a decision means for determining the pixel data to be an edge when the pixel data is equal to the tri-state values. The edge detection apparatus can remove noise without an additional low pass filters, simplify the hardware and do real time process.
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Citations
11 Claims
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1. An edge detection method comprising:
a converting step comprising steps for obtaining a mean value Mi of pixel data Z;
in an n×
n window and converting said pixel data in said n×
n window into tri-state values Vj using said mean value Mi and a predetermined threshold value e ##EQU14## for j=1, 2 . . . , r;
a comparing step for comparing Vj, which is said pixel data represented in tri-state values, with four pre-specified edge patterns W1, W2, W3 and W4, where ##EQU15## where the superscript T represents the transpose of the matrix; and
decision steps for determining said pixel data to be an edge if Vj is equal to any one of said four pre-specified edge patterns, and otherwise not to be an edge.
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2. An edge detection apparatus comprising:
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conversion means comprising;
a mean value calculation circuit for obtaining a mean value of pixel data in a 3×
3 window centered by an input pixel of interest and a conversion circuit for B×
B converting said pixel data into tri-state values using said mean value and a predetermined threshold value;matching means for obtaining inner products of said tri-state values and pre-specified edge patterns; and decision means for determining said pixel of interest to be an edge when said tri-state values are equal to any one of said edge patterns, and otherwise not to be an edge. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification