1. An image acquiring apparatus, comprising: an image acquiring unit for acquiring an image, which comprises a plurality of pixels each corresponding to a piece of image data, wherein a location of each of the pixels is represented by an actual coordinate; and an image processor, which comprises: a stray device for shifting the actual coordinate corresponding to each of the pixels by a random coordinate variable to obtain a virtual coordinate corresponding to each of the pixels; a compensation parameter generator for receiving the virtual coordinates and thus outputting a virtual compensation parameter corresponding to each of the pixels; and an image processing unit for adjusting the image data of each of the pixels according to the corresponding virtual compensation parameter.