System and method to increase effective dynamic range of image sensors
First Claim
Patent Images
1. A method of effectively increasing the dynamic range of an image sensor, the method comprising:
- capturing multiple images of a scene taken at different exposures;
searching a selected image of the multiple images for overexposed and underexposed portions based on a pixel value indicative of luminance;
analyzing portions in other images of the multiple images taken at lower exposures corresponding spatially to the overexposed portions in the selected image;
analyzing portions in other images of the multiple images taken at higher exposures corresponding spatially to the underexposed portions in the selected image; and
processing at least one of the analyzed portions with a machine vision application.
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Abstract
A system and method of increasing the dynamic range of image sensors by controlling the exposure (either electronically or mechanically) of multiple images and optionally forming a composite image from the properly exposed areas of the multiple images of varying exposure settings. Certain embodiments of the system and method utilize image processing techniques to determine the various exposure settings and to form the optional composite image. The properly exposed areas can be used directly by machine vision applications.
169 Citations
42 Claims
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1. A method of effectively increasing the dynamic range of an image sensor, the method comprising:
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capturing multiple images of a scene taken at different exposures;
searching a selected image of the multiple images for overexposed and underexposed portions based on a pixel value indicative of luminance;
analyzing portions in other images of the multiple images taken at lower exposures corresponding spatially to the overexposed portions in the selected image;
analyzing portions in other images of the multiple images taken at higher exposures corresponding spatially to the underexposed portions in the selected image; and
processing at least one of the analyzed portions with a machine vision application. - View Dependent Claims (2, 3)
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4. A method of effectively increasing the dynamic range of an image sensor, the method comprising:
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obtaining an image of a scene;
analyzing the image to identify one or more regions that are either too bright or too dark, wherein any one of the regions includes a plurality of pixels;
for any identified region that is identified as being too bright, obtaining a reduced exposure image;
for any identified region that is identified as being too dark, obtaining an increased exposure image; and
processing one or more of the properly exposed regions of the image and one or more properly exposed regions in the reduced and/or increased exposure images. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 17, 18, 19, 20, 21, 22, 24, 26, 27, 28, 29, 30, 31)
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13. A computer program storage medium storing instructions that when executed by a processor perform a method of increasing the dynamic range of an image sensor, the method comprising:
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obtaining a base image of a scene;
analyzing the base image to identify one or more regions that are either too bright or too dark, wherein any one of the regions includes a plurality of pixels;
for any identified region that is too bright, obtaining a reduced exposure image;
for any identified region that is too dark, obtaining an increased exposure image; and
processing the base image and one or more properly exposed regions in the reduced and/or increased exposure images.
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16. An image sensing system for effectively increasing the dynamic range of an image sensor comprising:
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means for acquiring an image of a scene a plurality of times with different exposures to obtain a plurality of images; and
means for segmenting the images into a plurality of image regions, wherein each region is indicative of a selected dynamic range, and wherein any one or more of the plurality of image regions are processed with a machine vision application.
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23. A method of effectively increasing the dynamic range of an image sensor, the method comprising:
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acquiring an image of a scene a plurality of times with different exposures to obtain a plurality of images;
segmenting the images into a plurality of image regions, wherein each region is indicative of a selected dynamic range; and
processing any one or more of the plurality of image regions with a machine vision application.
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25. An image acquisition system for effectively increasing the dynamic range of an image sensor, the system comprising:
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means for acquiring a plurality of images of a scene, each image having a different exposure; and
means for obtaining a plurality of image regions, wherein each region contains portions of a particular image with good dynamic range from the plurality of images, and wherein any one or more of the plurality of image regions are processed with a machine vision application.
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32. A method of effectively increasing the dynamic range of an image sensor, the method comprising:
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capturing multiple images of a scene taken in different lighting conditions;
searching an image of the multiple images for overexposed and underexposed portions based on a pixel value indicative of luminance;
reanalyzing the overexposed portions and the underexposed portions in the selected image corresponding to a spatially related portion in other images of the multiple images taken in different lighting conditions; and
processing at least one of the reanalyzed portions with a machine vision application. - View Dependent Claims (33, 34, 35, 37, 38, 39, 40, 41, 42)
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36. An image sensing system for effectively increasing the dynamic range of one or more image sensors, the system comprising:
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means for acquiring an image of a scene a plurality of times under different lighting conditions so as to obtain a plurality of images; and
means for segmenting the images into a plurality of image regions, wherein each region is indicative of a selected dynamic range, and wherein any one or more of the plurality of image regions are processed with a machine vision application.
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Specification