A hybrid image is an image that is perceived in one of two different ways, depending on viewing distance, based on the way humans process visual input. Hybrid images combine the low spatial frequencies of one picture with the high spatial frequencies of another picture, producing an image with an interpretation that changes with viewing distance.

Image filtering (or convolution) is a fundamental image processing tool. It is a technique for modifying or enhancing an image. This technique involves sliding a kernel over input image and performing convolution sum to update pixel value at the centre of the kernel. Different types of kernel can be used to perform defferent tasks like smoothing, sharpening, and edge enhancemen etc.