Imaging apparatus and image signal processing method producing wide dynamic range
First Claim
1. An imaging apparatus comprising:
- first signal processing means including a first analog-to-digital converter for converting an analog image signal into a first digital signal for partitioning the level of the analog image signal into a plurality of sections, a gain selector for selecting a corresponding gain from a plurality of different gains according to each of the plurality of sections, and an amplifier for amplifying the analog image signal by the plurality of gains according to each of the plurality of sections, at least two of the sections having different corresponding gains; and
second signal processing means including a second analog-to-digital converter for converting the analog image signal amplified by the plurality of different gains into a second digital signal, and a gamma corrector for non-linearly gamma-correcting the second digital signal according to each section of the plurality of sections on which the amplification of the analog image signal by the first signal processing means is based.
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Abstract
An imaging apparatus and method provides a wide dynamic range and is capable of displaying an improved color in low-luminance regions, and an image signal processing method thereof. In the imaging apparatus, a first process divides the voltage level of an analog image signal into a plurality of sections and amplifies the analog image signal with a plurality of different gains according to each section, and a second process converts the analog image signal amplified with the different gains into a digital signal, and non-linearly gamma-corrects the digital signal according to each section. The plurality of different gains may be inversely proportional to the luminance level of the analog image signal. Thus, the level of an analog signal in a low-luminance region is amplified with a gain greater than in a high-luminance region before gamma correction, so that signal-to-noise (S/N) ratio in the low-luminance region of an image is increased, thereby improving sensitivity of the image following gamma correction. Accordingly, a wide dynamic range is provided. An optional chrominance controller of the imaging apparatus controls chrominance gain of the digital signal and outputs the result, thereby displaying an improved color in low-luminance regions of the image.
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Citations
16 Claims
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1. An imaging apparatus comprising:
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first signal processing means including a first analog-to-digital converter for converting an analog image signal into a first digital signal for partitioning the level of the analog image signal into a plurality of sections, a gain selector for selecting a corresponding gain from a plurality of different gains according to each of the plurality of sections, and an amplifier for amplifying the analog image signal by the plurality of gains according to each of the plurality of sections, at least two of the sections having different corresponding gains; and
second signal processing means including a second analog-to-digital converter for converting the analog image signal amplified by the plurality of different gains into a second digital signal, and a gamma corrector for non-linearly gamma-correcting the second digital signal according to each section of the plurality of sections on which the amplification of the analog image signal by the first signal processing means is based. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An imaging apparatus comprising:
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an amplifier for amplifying an analog image signal by a predetermined gain;
an analog-to-digital converter for converting the amplified analog image signal into a digital signal;
a chrominance controller for controlling chrominance gain of the converted output of the analog-to-digital converter; and
a digital signal processor for processing the output of the chrominance controller. - View Dependent Claims (8, 9, 10)
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11. An image signal processing method comprising:
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converting an analog image signal into a first digital signal for partitioning the level of the analog image signal into a plurality of sections, selecting a corresponding gain among a plurality of different gains according to each of the plurality of sections and amplifying the image signal by the plurality of different gains according to each of the plurality of sections, at least two of the sections having different corresponding gains; and
converting the image signal amplified by the plurality of different gains into a second digital signal, and non-linearly gamma-correcting the second digital signal according to each section of the plurality of sections on which the amplification of the analog image signal is based. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification