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US 7,009,639 B1Granted
Color imaging by independently controlling gains of each of R, Gr, Gb, and B signals
AssigneeSony Corporation
InventorsHideho Une, Noriko Chino
Life of this patent
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Abstract
To eliminate an amplitude difference between luminance signals from pixels included in horizontal lines of color filters, caused by a sensitivity difference from one photosensor to another in a CCD, and reduce a horizontal stripe-like noise appearing in a monitoring image and captured image, there is provided an arithmetic circuit to calculate an amplitude difference in Gr and Gb signals based on an output from a four-channel detector to set gains multiplied by compensation factors, respectively, with which the white balance-processed Gr and Gb signals are equal in amplitude to each other, thereby controlling the gain of a while balance amplifier.
Claims10
A color imaging apparatus comprising:
- a solid-state image sensor having photosensors color-coded with three primary color filters formed like a matrix correspondingly to pixels of the solid-state image sensor, to provide three primary color signals acquired as captured image signals;
- a four-channel signal detecting means for detecting, from the three primary color signals provided from the solid-state image sensor, an R signal acquired from R pixels in a horizontal line of R, G, R, G, . . . , R and G color filters, a Gr signal acquired from the G pixels in the same horizontal line, a Gb signal acquired from G pixels in a horizontal line of G, B, G, B, . . . , G and B color filters, and a B signal acquired from the B pixels in the same horizontal line;
- a four-channel variable-gain amplifying means whose channels are controllable in gain independently of one another to amplify the R, Gr, Gb and B signals,
- wherein said R, Gr, Gb and B signals are amplified to substantially the same levels as one another, and wherein both luminance and chrominance signals are generated using the amplified four signals;
- and
- a gain controlling means for controlling, based on an output from the signal detecting means, the gains of R and B channels of the variable-gain amplifying means so that the R and B signals amplified by the variable-gain amplifying means are equal in level for an achromatic color image, and said gain controlling means generating a mean value of the outputs of Gr and Gb channels of the variable-gain amplifying means so that the amplitude difference between the luminance signal for the horizontal line of R, G, R, G, . . . , R and G color filters produced from the R and Gr signal and the luminance signal for the horizontal line of G, B, G, B, . . . , G and B color filters produced from the B and Gb signal is substantially reduced.
3 more elements
A color imaging method comprising the steps of:
- detecting, from the three primary color signals provided from the solid-state image sensor having photosensors color-coded with three primary color filters formed like a matrix correspondingly to pixels of the solid-state image sensor, an R signal acquired from R pixels in a horizontal line of R, G, R, G, . . . , R and G color filters, a Gr signal acquired from the G pixels in the same horizontal line, a Gb signal acquired from G pixels in a horizontal line of G, B, G, B, . . . , G and B color filters, and a B signal acquired from the B pixels in the same horizontal line;
- amplifying the R, Gr, Gb and B signals by a four-channel variable-gain amplifying means whose channels are controllable in gain independently of each other,
- wherein said R, Gr, Gb and B signals are amplified to substantially the same levels as one another, and wherein both luminance and chrominance signals are generated using the amplified four signals;
- controlling, by a gain controlling means, based on an output from the signal detecting means, the gains of R and B channels of the variable-gain amplifying means so that the R and B signals amplified by the variable-gain amplifying means are equal in level for an achromatic color image;
- and
- generating a mean value of the outputs of Gr and Gb channels of the variable-gain amplifying means so that the amplitude difference between the luminance signal for the horizontal line of R, G, R, G, . . . , R and G color filters produced from the R and Gr signal and the luminance signal for the horizontal line of G, B, G, B, . . . , G and B color filters produced from the B and Gb signal is substantially reduced.
3 more elements
Dependencies are inferred from the claim text.