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# Comparing Images Visually

[Laboratory]

In many cases, one is interested to compare image visually. The simplest way is to display them in separate windows and put them close together. The danger of this technique is that, the rendering algorithm used by the separate window displays can be different, depending on the data contents.

A safer way to compare images visually is to put them together in a single image, so that one is sure that all the pixels were rendered in the same way. There are basicly two ways to put the images in a single image for visual comparison. The images can be put side by side forming a mosaic of images, or the images can be put as a frame in a sequence of images.

Below, we have two original grey level images put together in a single larger image.

mosaic image

When making the original images as frames in a sequence, the images are arranged as shown in the figure below. You need an image sequencer tool such as khoros animate to visualize the sequence.

sequence of four images

- Lab: Comparing Images Visually