Once the stimulus is inside the computer it may need to be manipulated in some way or other. This is often done as part of an experiment in which one parameter of the stimulus, such as contrast, is changed as a consequence of responses from an observer. There are many processes encompassed by the idea of manipulation and only a few can be discussed here. Many of the operations that are performed on real-life images such as filtering and feature extraction are normally classed as image processing and well dealt with in other literature. Two of the principal techniques used in visual stimulus generators involve the summation of two components of a stimulus using interleaving and the use of look-up tables.

^ Back to top