Automatic contrast correctin useful in video-to-print apparatus
First Claim
1. An automatic contrast correction apparatus for correcting the contrast of a picture represented by color video signals, comprising:
- an analog-to-digital converter for sequentially receiving said color video signals and converting said received signals into digital data;
memory means for storing said digital data;
amplification means comprising a plurality of amplifiers having different amplification factors switchably connected in parallel between said analog-to-digital converter and said memory means;
extracting means for receiving said digital data supplied from said analog-to-digital converter and extracting data therefrom corresponding to a predetermined effective picture screen; and
microcomputer means responsive to said extracted data and a predetermined reference value for calculating an average value of the color signal data supplied from said extraction means, comparing said average value with said predetermined reference value corresponding to an optimized contrast, and switchably connecting one of said plurality of amplifiers between said analog to digital converter and said memory means depending upon the compared result.
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Accused Products
Abstract
Disclosed is an automatic contrast correction method and apparatus for optimizing contrast of a picture screen. There is included an effective picture screen extractor for extracting video data corresponding to the effective picture screen among video data in the picture screen, a plurality of amplifiers for receiving the video data and amplifying the received video data for output, and a microcomputer for comparing the average value which is calculated from the video data of the effective picture screen with a previously set reference value and regulating an amplification factor by supplying a control signal to the amplifiers according to the comparison result. Even if video images photographed toward the sun are printed, it can be prevented from being printed in a dark state, thereby obtaining a good quality of picture.
8 Citations
8 Claims
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1. An automatic contrast correction apparatus for correcting the contrast of a picture represented by color video signals, comprising:
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an analog-to-digital converter for sequentially receiving said color video signals and converting said received signals into digital data; memory means for storing said digital data; amplification means comprising a plurality of amplifiers having different amplification factors switchably connected in parallel between said analog-to-digital converter and said memory means; extracting means for receiving said digital data supplied from said analog-to-digital converter and extracting data therefrom corresponding to a predetermined effective picture screen; and microcomputer means responsive to said extracted data and a predetermined reference value for calculating an average value of the color signal data supplied from said extraction means, comparing said average value with said predetermined reference value corresponding to an optimized contrast, and switchably connecting one of said plurality of amplifiers between said analog to digital converter and said memory means depending upon the compared result. - View Dependent Claims (2, 4)
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3. An automatic contrast correction apparatus according to claim further comprising an effective picture screen operation controller connected to said extraction means for setting a magnitude of the effective picture screen necessary for extraction of the data in said effective picture screen extraction means.
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5. An automatic contrast correction method for correcting the contrast of a picture represented by color video signals comprising the steps of:
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(a) sequentially receiving respective color video signals and converting the received signal into digital data; (b) receiving the digital data and extracting the data corresponding to a previously set effective picture screen; (c) calculating an average value of color signals with respect to the extracted data; (d) comparing the average value with a reference value which is previously set so as to have an optimized contrast; and (e) amplifying the digital data by a selected one of several predetermined amplification factors, selected based on the compared result. - View Dependent Claims (6, 7, 8)
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Specification