Digital signal conversion method and apparatus for converting photoelectrically converted video signals
First Claim
1. A digital signal conversion apparatus for converting an input video signal into a converted video signal, the apparatus comprising:
- knee point determination means for automatically determining knee point information based on brightness information; and
signal processing means for inputting said input video signal, outputting said brightness information according to said input video signal and converting said input video signal into said converted video signalwherein said input video signal has a first dynamic range which is directly proportional to said brightness information, wherein one of said signal processing means and a separate signal processing system has a second dynamic range,wherein an amount by which said first dynamic range exceeds said second dynamic range corresponds to an excessive light quantity range.wherein said signal processing means converts said input video signal into said converted video signal by using an input/output characteristic which corresponds to said excessive light quantity range. andwherein a size of said excessive light quantity range varies according to said knee point information.
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Abstract
A digital signal conversion apparatus converts an input video signal having a first dynamic range into a converted video signal having a dynamic range which is smaller than the first dynamic range. In particular, the conversion apparatus includes a digital signal processor (DSP) and a knee point determiner. The DSP inputs the input video signal and converts such signal into the converted video signal based on a selected one of a plurality of input/output (I/O) characteristic functions stored in the DSP. Furthermore, the DSP generates brightness information based on the magnitude of the first dynamic range of input video signal. The knee point determiner inputs the brightness information and generates knee point information based on the brightness information. As a result, the DSP selects one of the I/O characteristic functions in accordance with the knee point information such that the DSP can appropriately convert the input video signal into the converted video signal.
18 Citations
29 Claims
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1. A digital signal conversion apparatus for converting an input video signal into a converted video signal, the apparatus comprising:
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knee point determination means for automatically determining knee point information based on brightness information; and signal processing means for inputting said input video signal, outputting said brightness information according to said input video signal and converting said input video signal into said converted video signal wherein said input video signal has a first dynamic range which is directly proportional to said brightness information, wherein one of said signal processing means and a separate signal processing system has a second dynamic range, wherein an amount by which said first dynamic range exceeds said second dynamic range corresponds to an excessive light quantity range. wherein said signal processing means converts said input video signal into said converted video signal by using an input/output characteristic which corresponds to said excessive light quantity range. and wherein a size of said excessive light quantity range varies according to said knee point information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 26, 27)
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10. A digital signal conversion method for converting an input video signal having a magnitude within a first dynamic range into a converted video signal having a magnitude within a second dynamic range said digital signal conversion method comprising the steps of:
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(a) storing input/output characteristics which respectively correspond to knee point information values; (b) generating a particular knee point information value according to brightness information of said input video signal, wherein said brightness information corresponds to said first dynamic range of said input video signal; and (c) converting said input video signal into said converted video signal having said magnitude within said second dynamic range based on a particular input/output characteristic which corresponds to said particular knee point information value. - View Dependent Claims (11, 12, 13, 14, 28, 29)
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15. A digital signal conversion apparatus for converting an input video signal into a converted video signal, the apparatus comprising:
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signal processing means for inputting said input video signal and converting said video signal into said converted video signal, wherein said input video signal has first brightness values within a first dynamic range and said converted video signal has second brightness values within a second dynamic range, wherein said signal processing means contains a plurality input/output characteristic functions, selects one of said input/output characteristic functions as a selected input/output characteristic function, and converts said first brightness values within said first dynamic range into said converted video signal having second brightness values within said second dynamic range in accordance with said selected input/output characteristic function, and wherein said signal processing means outputs brightness information based on said first brightness values of said input video signal; and knee point determination means for inputting said brightness information, selecting a selected knee point information value from among a plurality of knee point information values based on said brightness information, and outputting said selected knee point information value, wherein said signal processing means inputs said selected knee point information value and selects said selected input/output characteristic function based on said selected knee point information value. - View Dependent Claims (17, 25)
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16. The digital signal conversion apparatus according to
an amount by which said first dynamic range exceeds said second dynamic range corresponds to an excessive light quantity range, and said knee point determination means selects said selected knee point information value such that said selected knee point information value corresponds to a size of said excessive light quantity range.
Specification