Shading correction device
First Claim
Patent Images
1. A device for carrying out the shading correction of an image signal on the basis of a reference data obtained by scanning a reference density reflecting plate comprising:
- image sensing means for converting light image information into an electrical image signal, said image sensing means being capable of storing an accumulated charge by scanning along different lines on said reflecting plate thereby forming an expanded image signal when supplied as an output;
control means for controlling the supply of said output from said image sensing means is an ordinary image signal or said expanded image signal;
averaging means for taking an average of said expanded image signal to form said reference data; and
correction means for supplying a correction signal to be used in shading correction in response to said reference data.
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Abstract
A device for carrying out the shading correction of an image signal is provided. The present device includes an image sensor capable of scanning a reference density reflecting plate over a predetermined number of times along different scanning lines and averaging means for taking an average among the repeated scannings thereby forming an error-free reference data to be later used in the operation of shading correction.
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Citations
12 Claims
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1. A device for carrying out the shading correction of an image signal on the basis of a reference data obtained by scanning a reference density reflecting plate comprising:
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image sensing means for converting light image information into an electrical image signal, said image sensing means being capable of storing an accumulated charge by scanning along different lines on said reflecting plate thereby forming an expanded image signal when supplied as an output; control means for controlling the supply of said output from said image sensing means is an ordinary image signal or said expanded image signal; averaging means for taking an average of said expanded image signal to form said reference data; and correction means for supplying a correction signal to be used in shading correction in response to said reference data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for carrying out the shading correction of an image signal supplied from a one-dimensional solid-state sensor which receives the light reflected from an original document to be read through an optical system, said image sensor being optically moved relative to said original document while scanning in the direction perpendicular to the direction of optical relative motion between said image sensor and original document, said method comprising the steps of:
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scanning a reference density reflecting plate by said image sensor over a predetermined number of times along different scanning lines on said plate thereby accumulating image data in said image sensor; taking an average of said image data accumulated in said image sensor to define a reference data; and carrying out a shading correction operation on the basis of said reference data.
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Specification