发明名称 |
Apparatus for correcting a black level of a video signal. |
摘要 |
A pedestal clamping device clamps a pedestal level of an input video signal in response to a predetermined pedestal voltage, and converts the input video signal into a clamped video signal. A black-level expanding device expands a tone of a black portion of the clamped video signal, and converts the clamped video signal into a black-level expanded video signal. A color greatest detecting device detects a greatest of color signals of the input video signal. A adding device adds an output signal from the color greatest detecting device and the pedestal voltage. A black-level comparing device detects a blackest portion of the black-level expanded video signal; compares the detected blackest portion of the black-level expanded video signal with the output signal from the adding device; and controls a degree of expanding the black tone by the black-level expanding device in response to a difference between the detected blackest portion of the black-level expanded video signal and the output signal from the adding device. <IMAGE>
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申请公布号 |
EP0460595(A2) |
申请公布日期 |
1991.12.11 |
申请号 |
EP19910109094 |
申请日期 |
1991.06.04 |
申请人 |
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. |
发明人 |
KAGEYAMA, ATSUHISA |
分类号 |
H04N5/20;H04N5/57;H04N9/68;H04N9/72 |
主分类号 |
H04N5/20 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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