Image sensing device having expanded dynamic range

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.gtoreq.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.