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US 7,612,813 B2Granted
Auto exposure for digital imagers
AssigneeAptina Imaging Corporation
InventorKevin Hunter
Life of this patent
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Abstract
An apparatus and method for performing automatic exposure control based on current measured luminance of an image and dynamic/modifiable target luminance levels. Exposure adjustments and/or adjustments to the dynamic/modifiable target luminance windows are based on the measured luminance and threshold settings to improve image quality while avoiding oscillations and other problems typically associated with automatic exposure.
Claims29
A processor implemented method of performing automatic exposure control for an imager, said method comprising the steps of:
- inputting into the processor a current luminance of an image captured by the imager;
- comparing in the processor the current luminance to an adjustable target luminance level;
- measuring a maximum color saturation;
- determining if the maximum color saturation is greater than a maximum saturation limit;
- and
- adjusting via the processor one of an image exposure setting and the target luminance level based on results of the comparing and determining steps,
- wherein said adjusting step increases the target luminance level if it is determined that the maximum color saturation is not greater than the maximum saturation limit.
4 more elements
An imaging device comprising:
- an array of pixels for capturing an image;
- image processing circuitry for obtaining current luminance of the image;
- and
- an automatic exposure control block connected to said image processing circuit, said automatic exposure control block compares the current luminance to an adjustable target luminance level, measures a maximum color saturation, determines if the maximum color saturation is greater than a maximum saturation limit, and adjusts one of an image exposure setting and the target luminance level based on results of the comparison and maximum color determination, said automatic exposure block increasing the target luminance level if it is determined that the maximum color saturation is not greater than the maximum saturation limit.
1 more element
A system comprising:
- a processor;
- and
- and an imaging device coupled to said processor, said imaging device comprising:
- an array of pixels for capturing an image,
- image processing circuitry for obtaining current luminance of the image, and
- an automatic exposure control block connected to said image processing circuit, said automatic exposure control block compares the current luminance to an adjustable target luminance level, measures a maximum color saturation, determines if the maximum color saturation is greater than a maximum saturation limit, and adjusts one of an image exposure setting and the target luminance level based on results of the comparison and maximum color determination, said automatic exposure block increasing the target luminance level if it is determined that the maximum color saturation is not greater than the maximum saturation limit.
3 more elements
Dependencies are inferred from the claim text.