IMAGE PROCESSING DEVICE FOR CONTROLLING PIXEL OUTPUT LEVEL AND OPERATING METHOD THEREOF

An image sensor includes a pixel array that includes a first pixel group located in a first row and including a first select transistor and a first floating diffusion region, a second pixel group located in a second row and including a second select transistor and a second floating diffusion region, and a column line connected to both the first pixel group and the second pixel group. While charges generated by a photoelectric conversion element of the first pixel group are transferred to the first floating diffusion region, the first select transistor is turned off, the second select transistor is turned on, and a first voltage is applied to the column line through the second select transistor. A photoelectric conversion element of the second pixel group generates charges prior to the photoelectric conversion element of the first pixel group, so as to be transferred to the second floating diffusion region.