FIG. 7(a) presents charts each schematically illustrating an example of combination processing may be executed to combine pixel signals from the nine pixels arranged over three rows× three columns in the image sensor 3 according to the second embodiment. It is to be noted that only three× three=nine pixels 10 and the arithmetic unit 50b among the arithmetic units 50 are shown in relation to the example presented in FIG. 7(a) and also in relation to the example presented in FIG. 7(b), which will be explained later, so as to simplify the explanation. The horizontal combining unit 40 in the example presented in FIG. 7(a) includes a switch SWa that connects/disconnects the first vertical signal line VL1a with/from the first vertical signal line VL1b and a switch SWb that connects/disconnects the first vertical signal line VL1b with/from the first vertical signal line VL1c.
The arithmetic unit 50b includes a first input unit Ia through a sixth input unit If. The first input unit Ia is connected to the first vertical signal line VL1a, and the second input unit Ib is connected to the second vertical signal line VL2a. The third input unit Ic is connected to the first vertical signal line VL1b, the fourth input unit 1d is connected to the second vertical signal line VL2b, the fifth input unit Ie is connected to the first vertical signal line VL1c, and the sixth input unit If is connected to the second vertical signal line VL2c.
