1. An image correction method, arranged for processing an original image to obtain a corrected image, wherein the original image is a non-rectangular-shaped image, and the corrected image is a rectangular-shaped image, and the image correction method comprising: receiving the original image from an image sensor; regarding each pixel of the original image, calculating a horizontal distance and a vertical distance between the pixel and a reference point in the original image; determining a horizontal ratio parameter and a vertical ratio parameter according to the horizontal distance and the vertical distance between the pixel and the reference point in the original image; performing an approximately non-linear regression calculation on the horizontal ratio parameter, the vertical ratio parameter and a coordinate of the pixel to obtain a position of the pixel in the corrected image; and determining a pixel value of the pixel of the corrected image by referring to a pixel value of the pixel of the original image.