Image sensing device having expanded dynamic range
First Claim
1. An image sensing device to obtain a composite picture with an expanded dynamic range by combining plural pictures with different exposures comprising:
- at least one image sensing element which photographs an object with at least two different exposures;
a control device for changing said exposures to said image sensing element at n steps (n≧
2, integer) and controlling said image sensing element to output n sets of pictures taken with said n steps of exposures; and
a calculating device for creating said composite picture with said expanded dynamic range, by combining first and second pictures taken with consecutive two exposures out of said n steps of exposures, said second picture being taken with a larger exposure than said first picture;
wherein said calculating device creates an intermediate composite picture with an intermediate expanded dynamic range by calculating a gray value of said second picture in a saturation region thereof based on a gray value of said first picture, utilizing the two gray values of said first and second pictures and two weight coefficients, said two weight coefficients being decided by said gray value of one of said first and second pictures, thereby reducing n sets of pictures to n-1 sets; and
said control device repeats the proceeding process with respect to said n-1 sets of pictures to obtain a final composite picture with the most expanded dynamic range.
1 Assignment
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Accused Products
Abstract
An image sensing device is provided with an expanded dynamic range when it photographs a moving object. A first gray value D1 of first picture taken with first exposure time is read in the first time interval and a second gray value D2 of second picture taken with second exposure time is read in the second time interval. Two function values f(D2) and g(D2) are calculated with respect to the second gray value D2. Then, a weight coefficient with respect to the function f(D2) is multiplied by the first gray value D1 and a weight coefficient with respect to the function g(D2) is multiplied by the second gray value D2. Those multiplied gray values are summed up. Such calculation of multiplying and summing up is carried out in each picture element of the first picture and the second picture, respectively.
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Citations
9 Claims
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1. An image sensing device to obtain a composite picture with an expanded dynamic range by combining plural pictures with different exposures comprising:
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at least one image sensing element which photographs an object with at least two different exposures; a control device for changing said exposures to said image sensing element at n steps (n≧
2, integer) and controlling said image sensing element to output n sets of pictures taken with said n steps of exposures; anda calculating device for creating said composite picture with said expanded dynamic range, by combining first and second pictures taken with consecutive two exposures out of said n steps of exposures, said second picture being taken with a larger exposure than said first picture;
wherein said calculating device creates an intermediate composite picture with an intermediate expanded dynamic range by calculating a gray value of said second picture in a saturation region thereof based on a gray value of said first picture, utilizing the two gray values of said first and second pictures and two weight coefficients, said two weight coefficients being decided by said gray value of one of said first and second pictures, thereby reducing n sets of pictures to n-1 sets; andsaid control device repeats the proceeding process with respect to said n-1 sets of pictures to obtain a final composite picture with the most expanded dynamic range. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An image sensing device to obtain a composite picture with an expanded dynamic range by combining plural pictures with different exposures comprising:
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at least one image sensing element which photographs an object with at least two different exposures; a control device for changing said exposures to said image sensing element at n steps (n≧
2, integer) and controlling said image sensing element to output n sets of pictures taken with said n steps of exposures;multiplying means for multiplying each gray value of said n sets of pictures by each weight coefficient decided by n sets of functions with respect to a first gray value of a first picture taken with the smallest exposure, respectively; and an adder for summing up said each gray value weighted by said multiplying means; wherein said control device controls said multiplying means and said adder and outputs a result of said adder as said composite picture with said expanded dynamic range based on said each gray value of said n sets of pictures, for each picture element corresponding to said n sets of pictures. - View Dependent Claims (9)
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Specification