1. Definition

Morphing is derived from the Greek word morphe which means form or shape. It is an image processing technique typically used as an animation tool for the “metamorphosis” from one image to another. It should not be confused with “morphological” impage processing operators which detect image features.

2. Simple ideas

The morph process constists of warping two images so that they have the same "shape", and then cross dissolving the resulting images. Cross-dissolving is simple; the major problem is how to warp an image. So the idea is to specify a warp that distorts the first image into the second. As the metamorphosis proceeds, the first image is gradually distorted and is faded out,  while the second image starts out totally distorted toward the first and is faded in.
Image Warping
Figure1  Process of Morphing

3. Applications

Finding examples of morphing is a matter of watching commercials on TV or going to a movie. Almost any film with Industrial Light and Magic or any other graphics studio's name in the credits is likely to include morphing.