1. A method for dividing an image area, comprising: a reading step: reading a pixel value of a current pixel and pixel values of multiple adjacent pixels adjacent to the current pixel in an image; a calculation step: calculating a difference between the pixel values of the current pixel and each adjacent pixel, so as to obtain a pixel difference value set, the pixel difference value set comprising multiple pixel difference values; a processing step: comparing each pixel difference value with a corresponding dynamic threshold in sequence, and determining all adjacent pixels in a same sub-image area as the current pixel, the current pixel and all the adjacent pixels of the current pixel in the same sub-image area constituting one sub-image area; and a traversal step: traversing each pixel in the image, and performing the reading step, the calculation step, and the processing step on each pixel in sequence, so as to acquire multiple sub-image areas of the image.