Color imaging apparatus including a means for electronically non-linearly expanding and compressing dynamic range of an image signal
First Claim
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1. A logarithmic color imaging apparatus comprising:
- an imaging device for converting a light image of an object to at least one electric output signal;
a color separating means for separating each output signal of said imaging device into separate output signals for different primary colors or auxiliary colors;
a first logarithmic compressing means for logarithmically compressing the output signals of said color separating means for the different primary colors or auxiliary colors;
an inverse-logarithmic converting means for inverse-logrithmically converting output signals of said first logarithmic compressing means;
a matrix-converting means for linear-matrix-converting output signals of said inverse-logarithmic converting means;
a second logarithmic compressing means for logarithmically compressing output signals of said matrix-converting means; and
a color signal compounding means for producing a logarithmically compressed brightness signal from output signals of said second logarithmic compressing means.
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Abstract
A color imaging apparatus includes means for electronically non-linearly expanding or compressing the dynamic range of an image signal output therefrom. Separate output signals of respective brightness for different colors are logarithmically compressed, inverse-logarithmically converted, then linear-matrix-converted and multipled by a compression factor of brightness level for the respective color signals to produce a logarithmically compressed color signal without varying the tone.
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Citations
21 Claims
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1. A logarithmic color imaging apparatus comprising:
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an imaging device for converting a light image of an object to at least one electric output signal; a color separating means for separating each output signal of said imaging device into separate output signals for different primary colors or auxiliary colors; a first logarithmic compressing means for logarithmically compressing the output signals of said color separating means for the different primary colors or auxiliary colors; an inverse-logarithmic converting means for inverse-logrithmically converting output signals of said first logarithmic compressing means; a matrix-converting means for linear-matrix-converting output signals of said inverse-logarithmic converting means; a second logarithmic compressing means for logarithmically compressing output signals of said matrix-converting means; and a color signal compounding means for producing a logarithmically compressed brightness signal from output signals of said second logarithmic compressing means. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19)
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7. A logarithmic color imaging apparatus comprising:
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a field sequential type illuminating means for sequentially illuminating an object with light of a plurality of different colors; an imaging device for converting a light image of said object to at least one electric output signal in coordination with said field sequential type illuminating means; a memory means for switching each signal of said imaging device in synchronism with said field sequential type illuminating means to produce separate output signals for the different colors and memorizing the same; a first logarithmic compressing means for logarithmically compressing output signals of said memory means; an inverse-logarithmic converting means for inverse-logarithmically converting output signals of said first logarithmic compressing means; a matrix-converting means for linear-matrix-converting output signals of said inverse-logarithmic converting means; a second logarithmic compressing means for logarithmically compressing output signals of said matrix-converting means; and a color signal compounding means for producing a logarithmically compressed brightness signal from output signals of said second logarithmic compressing means.
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18. A logarithmic compression characteristic color imaging apparatus comprising an imaging device including a pair of color imaging devices for converting a light image to electric output signals, a pair of RGB separating circuits for separating the output signals of said pair of color imaging devices into three primary color signals and a logarithmic amplifying means for amplifying the color signals such that they have an approximately logarithmic characteristic.
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20. A logarithmically compressed color signal processing apparatus comprising:
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a first logarithmic compressing means for logarithmically compressing input color signals for respective primary colors or auxiliary colors; an inverse-logarithmic converting means for inverse-logarithmically converting output signals of said first logarithmic compressing means; a matrix-converting means for linear-matrix-converting output signals of said inverse-logarithmic converting means; a second logarithmic compressing means for logarithmically compressing output signals of said matrix-converting means; and a color signal compounding means for producing a logarithmically compressed brightness signal from output signals of said second logarithmic compressing means.
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21. An electronic camera reproducer comprising:
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a first logarithmic compressing means for logarithmically compressing signals for respective primary colors of a video signal recorded in a recording medium; an inverse-logarithmic converting means for inverse-logarithmically converting output signals of said first logarithmic compressing means; a matrix-converting means for linear-matrix-converting output signals of said inverse-logarithmic converting means; a second logarithmic compressing means for logarithmically compressing output signals of said matrix-converting circuit; and a color signal compounding means for compounding output signals of said second logarithmic compressing circuit and output signals of said first logarithmic compressing circuit.
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Specification