High intrascene dynamic range NTSC and PAL imager
First Claim
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1. An imager comprising:
- a first pixel circuit in a first pixel row for outputting at least a first pixel image signal accumulated during a first integration period;
a second pixel circuit in a pixel row different from the first pixel row for outputting at least a second pixel image signal accumulated during a second integration period, which is shorter than said first integration period; and
a sample and hold circuit configured to selectively acquire at least one of said first and second pixel image signals and perform a comparison of said first pixel image signal to a threshold signal value, and to output a pixel output signal generated from at least one of said first and second pixel image signals based on the result of said comparison.
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Abstract
The invention provides a new method and apparatus for NTSC and PAL image sensors which employs fusion of adjacent row pixel charge samples to generate image data for a row. A variety of fusion schemes are possible for fusing the pixel signals from the adjacent rows. The rows of pixels are scanned so that each scan takes an odd row signal sample and, in some cases, an adjacent even row signal sample when specified conditions are met. One sampled row of the two adjacent rows integrate an image with a first integration period while the other adjacent row integrates an image with a second integration period.
26 Citations
20 Claims
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1. An imager comprising:
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a first pixel circuit in a first pixel row for outputting at least a first pixel image signal accumulated during a first integration period; a second pixel circuit in a pixel row different from the first pixel row for outputting at least a second pixel image signal accumulated during a second integration period, which is shorter than said first integration period; and a sample and hold circuit configured to selectively acquire at least one of said first and second pixel image signals and perform a comparison of said first pixel image signal to a threshold signal value, and to output a pixel output signal generated from at least one of said first and second pixel image signals based on the result of said comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A readout system comprising:
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at least one sample and hold circuit configured to sample a first pixel signal from a first selected row of pixels having a first integration period, said sample and hold circuit further configured to selectively sample a second pixel signal from a second adjacent selected row of pixels, which has a second integration period shorter than said first integration period; a switching circuit coupled to said at least one sample and hold circuit and being configured to control sampling of said first and second pixel signals; and a comparator configured to determine if a sampled first pixel signal exceeds a threshold signal value, said switching circuit being further configured to operate said at least one sample and hold circuit to sample said first pixel signal and to provide a first output signal if said comparator determines that said threshold is exceeded by said sampled first pixel signal, and to operate said at least one sample and hold circuit to sample and hold said second pixel signal and to provide a second output signal when said threshold is not exceeded, wherein said first output signal is different from said second output signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification