Imaging apparatus and driving method of solid-state imaging device
A driving method of a solid-state imaging device including plural high-sensitivity pixels and plural low-sensitivity pixels that are arranged in mixed form in a manner of a two-dimensional array on a semiconductor substrate, the method including driving the solid-state imaging device in such a manner that an exposure period of the low-sensitivity pixels is set shorter than that of the high-sensitivity pixels.
1. A driving method of a solid-state imaging device including plural high-sensitivity pixels and plural low-sensitivity pixels that are arranged in mixed form in a manner of a two-dimensional array on a semiconductor substrate, the method comprising:
driving the solid-state imaging device in such a manner that an exposure period of the low-sensitivity pixels is set shorter than that of the high-sensitivity pixels,
wherein the exposure period of the low-sensitivity pixels is shortened to increase a difference between the exposure periods of the low-sensitivity pixels and the high-sensitivity pixels in case a bright/dark difference of an object image is large, and the exposure period of the low-sensitivity pixels is elongated to decrease a difference between the exposure periods of the low-sensitivity pixels and the high-sensitivity pixels in case the bright/dark difference is small.
2. The driving method according to claim 1 , wherein a pixel area of the high-sensitivity pixels is wider than that of the low-sensitivity pixels.
3. An imaging apparatus comprising:
a solid-state imaging device including plural high-sensitivity pixels and plural low-sensitivity pixels that are arranged in mixed form in a manner of a two-dimensional array on a semiconductor substrate; and
a control unit which drives the solid-state imaging device in such a manner that an exposure period of the low-sensitivity pixels is set shorter than that of the high-sensitivity pixels, and combines second image data produced by the low-sensitivity pixels with first image data produced by the high-sensitivity pixels to generate composed image data having a wider dynamic range than the first image data,
wherein the control unit shortens the exposure period of the low-sensitivity pixels in case a bright/dark difference of an object image is large in order to increase a difference between the exposure periods of the low-sensitivity pixels and the high-sensitivity pixels, and elongates the exposure period of the low-sensitivity pixels in case the bright/dark difference is small in order to decrease a difference between the exposure periods of the low-sensitivity pixels and the high sensitivity pixels.
4. The imaging apparatus according to claim 3 , wherein a pixel area of the high-sensitivity pixels is wider than that of the low-sensitivity pixels.
5. The imaging apparatus according to claim 4 , wherein the control unit compares the bright/dark difference with a threshold value, generates composed image data having a wider dynamic range than the first image data in case the bright/dark difference is larger than the threshold value, and elongates the exposure period of the low-sensitivity pixels to decrease a sensitivity difference from the high-sensitivity pixels and generates high-resolution image data using image data read from the high-sensitivity pixels and image data read from the low-sensitivity pixels in case the bright/dark difference is smaller than the threshold value.
6. The imaging apparatus according to claim 4 , further comprising an input unit which receives an external instruction as to whether to compose image data having a wider dynamic range than the first image data or generate high-resolution image data.
7. The imaging apparatus according to claim 3 , wherein the control unit compares the bright/dark difference with a threshold value, generates composed image data having a wider dynamic range than the first image data in case the bright/dark difference is larger than the threshold value, and elongates the exposure period of the low-sensitivity pixels to decrease a sensitivity difference from the high-sensitivity pixels and generates high-resolution image data using image data read from the high-sensitivity pixels and image data read from the low-sensitivity pixels in case the bright/dark difference is smaller than the threshold value.
8. The imaging apparatus according to claim 3 , further comprising an input unit which receives an external instruction as to whether to compose image data having a wider dynamic range than the first image data or generate high-resolution image data.