An electronic device comprising a processing unit and a memory that stores a plurality of program instructions. The processing unit executes the program instructions to perform the following steps: (a) storing pixel data of multiple pixels of a picture in the memory, the number of the pixels being greater than the number of pixels in one horizontal line of the picture; (b) performing an integral image operation on the pixel data to obtain integral image data; (c) storing the integral image data in the memory; (d) using the integral image data to calculate a low-frequency component of a target pixel of the picture; and (e) based on the low-frequency component, selectively performing a temporal noise reduction operation on the target pixel.