Readout technique for increasing or maintaining dynamic range in image sensors
AssigneeAptina Imaging Corporation
InventorsEspen Olsen, Jorgen Moholt
Life of this patent
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Abstract
The apparatus and method provide a readout technique and circuit for increasing or maintaining dynamic range of an image sensor. The readout technique and circuit process each pixel individually based on the magnitude of the readout signal. The circuit includes a gain amplifier amplifying the readout analog signal, a level detection circuit for determining the signal's magnitude, a second gain amplifier applying a gain based on the signal magnitude and an analog-to-digital converter digitizing the signal and a circuit for multiplying or dividing the signal. The method and circuit allow for a lower signal-to-noise ratio while increasing the dynamic range of the imager.
Claims16
-16. (canceled)
A pixel signal processing circuit comprising:
- a pixel signal input;
- a variable gain amplifier for amplifying a pixel signal at said input by an amount which varies depending on a signal level of the pixel signal;
- and
- an analog-to-digital converter for digitizing the amplified signal.
A method of increasing dynamic range of an imager, said method comprising:
- amplifying a signal from a pixel in an imager pixel array;
- determining the magnitude of the amplified pixel signal;
- applying a gain to the pixel signal, wherein the gain applied to the signal varies is based on the determined signal magnitude;
- and
- digitizing the pixel signal.
A method for increasing dynamic range, said method comprising:
- subtracting an offset from a signal from a pixel in an imager pixel array;
- amplifying said signal;
- determining a magnitude of the amplified signal;
- applying a gain to the pixel signal, wherein the gain applied to the signal varies is based on the signal magnitude;
- digitizing the signal;
- and
- multiplying said digitized pixel signal.
(canceled)
A method of operating an imager device, said method comprising:
- for each of a plurality of selected pixel in a pixel area, sampling and holding a readout signal;
- amplifying said readout signal;
- detecting the level of said amplified signal;
- determining a gain to be applied to the signal, wherein the gain to be applied to the signal varies based on said detected signal level;
- applying the determined gain to the signal;
- and
- digitizing said signal.
Dependencies are inferred from the claim text.