1. A method for estimating image noises implemented by software residing in hardware, the method comprising: obtaining spatial information of an image by calculating a spatial noise estimation value to be utilized as the spatial information of the image; obtaining temporal information of the image; and determining a spatial noise or a temporal noise of the image according to the spatial information and the temporal information residing in hardware by setting the spatial noise estimation value as the spatial noise of the image if the spatial noise estimation value is less than a predetermined threshold.