Image Sensor with Interleaved Hold for Single-Readout Depth Measurement
First Claim
1. A method for processing pixel signal values from an image sensor having a plurality of pixels, each pixel being configured to generate a respective pixel signal value by demodulating received light using a reference signal, the method comprising:
- controlling at least a first subset of the plurality of pixels to generate respective pixel signal values, based on a first reference signal applied to the first subset of pixels, for a first exposure;
subsequent to the first exposure, controlling the first subset of the plurality of pixels to hold their respective pixel signal values;
while the first subset of the plurality of pixels are holding their respective pixel signal values, controlling a second subset of the plurality of pixels to generate respective pixel signal values, based on a second reference signal applied to the second subset of pixels, for a second exposure;
subsequent to the second exposure, controlling the second subset of the plurality of pixels to hold their respective pixel signal values; and
reading out the pixel signal values from the first and second subsets of the plurality of pixels and converting the read pixel signal values to digital pixel values.
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Accused Products
Abstract
Time-of-flight (TOF) systems and techniques whereby a first exposure obtains pixel measurements for a first subset of pixels of a pixel array, using a first reference signal. For a second exposure, the first subset of the pixels, e.g., every second line of the pixel array, are set to a “hold” state, so that values obtained from the first measurement are maintained. A second exposure using a second reference signal is performed for a second subset of the pixels. The first and second reference signals may have different phase shifts relative to a signal modulating an optical signal being measured. The result is an array of pixels in which the first and second subsets hold results of the first and second exposures, respectively. These pixel values can then be read out all at once, with certain calculations being performed directly as pixel values are read from the pixel array.
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14 Claims
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1. A method for processing pixel signal values from an image sensor having a plurality of pixels, each pixel being configured to generate a respective pixel signal value by demodulating received light using a reference signal, the method comprising:
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controlling at least a first subset of the plurality of pixels to generate respective pixel signal values, based on a first reference signal applied to the first subset of pixels, for a first exposure; subsequent to the first exposure, controlling the first subset of the plurality of pixels to hold their respective pixel signal values; while the first subset of the plurality of pixels are holding their respective pixel signal values, controlling a second subset of the plurality of pixels to generate respective pixel signal values, based on a second reference signal applied to the second subset of pixels, for a second exposure; subsequent to the second exposure, controlling the second subset of the plurality of pixels to hold their respective pixel signal values; and reading out the pixel signal values from the first and second subsets of the plurality of pixels and converting the read pixel signal values to digital pixel values. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An image processing system comprising:
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a sensor comprising a plurality of pixels configured to generate a respective plurality of pixel signal values in response to received light, wherein each pixel is configured to obtain its respective pixel signal value by demodulating received light using a reference signal; a reference signal generator configured to generate the reference signal and to provide the reference signal to the plurality of pixels, and an analog-to-digital converter (ADC) circuit operatively coupled to the plurality of pixels, and control circuitry configured to; control the reference signal generator to generate a first reference signal; control at least a first subset of the plurality of pixels to generate respective pixel signal values, based on the first reference signal, for a first exposure; subsequent to the first exposure, control the first subset of the plurality of pixels to hold their respective pixel signal values; control the reference signal generator to generate a second reference signal, while the first subset of the plurality of pixels are holding their respective pixel signal values; while the first subset of the plurality of pixels are holding their respective pixel signal values, control a second subset of the plurality of pixels to generate respective pixel signal values, based on the second reference signal, for a second exposure; subsequent to the second exposure, control the second subset of the plurality of pixels to hold their respective pixel signal values; and
,read out the pixel signal values of the first and second subsets of pixels, for conversion to respective digital pixel values by the ADC circuit. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification