Image sensing apparatus which performs dynamic range expansion and image sensing method for dynamic range expansion
First Claim
1. An image sensing apparatus which sense an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
- histogram generating means for generating a histogram of signal levels of a first image sensed in a first exposure;
deciding means for deciding whether a dynamic range expansion processing is to be processed or not on the basis of the histogram generated by said histogram generating means;
parameter determination means for determining a plurality of parameters for sensing a plurality of images of the object in exposures which are different from the first exposure and from each other; and
image processing means for processing the first image and the plurality of images sensed by using the determined parameters to obtain a single image of the object.
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Abstract
An image sensing apparatus which senses an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, generates a histogram of signal levels of an image sensed in a proper exposure by using a histogram generator, automatically decides whether a dynamic range expansion processing is to be processed or not on the basis of the generated histogram by using a dynamic range expansion deciding unit, determines a parameter for sensing another image of the object in an exposure which is different from the proper exposure in accordance with a decision by the dynamic range expansion deciding unit by using a parameter determination unit, and obtains a single image of the object by processing the image sensed in the proper exposure and the image sensed by using the parameter determined by said parameter determination unit an image processing unit. When an image sensing apparatus is not equipped with a photometer, a pre-sensing operation is performed, an image sensed in the pre-sensing operation is analyzed to find a proper exposure, and this image is also used in the dynamic range expansion processing. A part or whole image data of a plurality of images which are obtained as above and necessary for the dynamic range expansion processing are compressed by a compressing unit and the compressed image data is used in the dynamic range expansion processing.
141 Citations
27 Claims
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1. An image sensing apparatus which sense an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
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histogram generating means for generating a histogram of signal levels of a first image sensed in a first exposure; deciding means for deciding whether a dynamic range expansion processing is to be processed or not on the basis of the histogram generated by said histogram generating means; parameter determination means for determining a plurality of parameters for sensing a plurality of images of the object in exposures which are different from the first exposure and from each other; and image processing means for processing the first image and the plurality of images sensed by using the determined parameters to obtain a single image of the object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An image sensing apparatus which sense an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
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histogram generating means for generating a histogram of signal levels of a first image sensed in a first exposure; deciding means for deciding whether a dynamic range expansion is to be performed or not by comparing at least one total number of events occurred in at least one predetermined range of the signal levels in the histogram generated by said histogram generating means to a threshold predetermined by a range of the signal levels; parameter determination means for determining a parameter for sensing a second image of the object in a second exposure which is different from the first exposure in accordance with a decision by said deciding means; and image processing means for obtaining a single image of the object by processing the first image and the second image which is sensed by using the parameter determined by said parameter determination means.
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8. An image sensing apparatus which sense an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
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histogram generating means for generating a histogram of signal levels of a first image sensed in a first exposure; deciding means for deciding whether a dynamic range expansion processing is to be processed or not on the basis of the histogram generated by said histogram generating means and a parameter indicating whether the dynamic range expansion processing is to be performed which is set by a user; parameter determination means for determining a parameter for sensing a second image of the object in a second exposure which is different from the first exposure in accordance with a decision by said deciding means; and image processing means for obtaining a single image of the object by processing the first image and the second image which is sensed by using the parameter determined by said parameter determination means.
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9. An image sensing apparatus which sense an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
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histogram generating means for generating a histogram of signal levels of a first image sensed in a first exposure; deciding means for deciding whether a dynamic range expansion processing is to be processed or not on the basis of the histogram generated by said histogram generating means; parameter determination means for determining a number of images to be sensed in different exposures which are different from the first exposure and parameters for sensing the images on the basis of at least one total number of events in at least one predetermined range of the signal levels in the histogram; and image processing means for obtaining a single image of the object by processing the first image and the images which are sensed in different exposures by using the parameters determined by said parameter determination means. - View Dependent Claims (10)
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11. An image processing apparatus which makes a single image with a widened dynamic range by processing a plurality of images obtained by sensing an object a plurality of times in different exposures, said apparatus comprising:
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an interface for receiving the plurality of images; histogram generating means for generating a histogram of signal levels of a first image out of the plurality of received images which is sensed in a first exposure; deciding means for deciding whether a dynamic range expansion processing is to be processed or not on the basis of the histogram generated by said histogram generating means; parameter determination means for determining a plurality of parameters for sensing a plurality of images of the object in exposures which are different from the first exposure and from each other in accordance with a decision by said deciding means; and image processing means for processing the first image and the plurality of images sensed by using the determined parameters to obtain a single image of the object. - View Dependent Claims (12)
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13. An image sensing method of sensing an object a plurality of times in different exposures to obtain a plurality of images and making a single image with a widened dynamic range by processing the plurality of sensed images, said method comprising:
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a histogram generating step of generating a histogram of signal levels of a first image sensed in a first exposure; a deciding step of deciding whether a dynamic range expansion processing is to be performed on the basis of the histogram generated at said histogram generating step; a parameter determination step of determining a plurality of parameters for sensing a plurality of images of the object in exposures which are different from the first exposure and from each other in accordance with a decision at said deciding step; and an image processing step of processing the first image and the plurality of images sensed by using the determined parameters to obtain a single image of the object.
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14. An image sensing apparatus which senses an object a plurality of times in different exposures to obtain a plurality of images and makes a single image with a widened dynamic range by processing the plurality of sensed images, said apparatus comprising:
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an image sensor for sensing the object so as to obtain an image and outputting the obtained image; operation means for finding a proper exposure by using a first image sensed in a first image sensing operation and a first exposure used to sense the first image; deciding means for deciding whether a dynamic range expansion processing is to be performed; image sensor control means for controlling said image sensor to sense a second image and a third image so that the first, second, and third images are sensed in proper, over, and under exposures on the basis of the proper exposure obtained by said operation means and the first exposure; and image processing means for, depending upon a decision by said deciding means, generating a single image by using the first, second and third images. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. An image sensing method of sensing an object a plurality of times in different exposures to obtain a plurality of images and making a single image with a widened dynamic range by processing the plurality of sensed images, said method comprising:
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a first image sensing step of sensing a first image of the object and outputting the first image; an operation step of finding a proper exposure by using the first image sensed at the first image sensing step and a first exposure used to sense the first image; a deciding step of deciding whether a dynamic range expansion processing is to be performed; a second image sensing step of sensing a second image and a third image so that the first, second, and third images are sensed in proper, over, and under exposures on the basis of the proper exposure obtained at said operation step and the first exposure; and an image processing step of, depending upon a decision at said deciding step, generating a single image by using the first, second and third images. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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Specification