shift-and-add method
image-stacking

The shift-and-add method (more recently "image-stacking" method) is a form of speckle imaging commonly used for obtaining high quality images from a number of short exposures with varying image shifts.

Modern webcams and camcorders have the ability to capture rapid short exposures with sufficient sensitivity for astrophotography, and these devices are used with a telescope and the shift-and-add method from speckle imaging (also known as image stacking) to achieve previously unattainable resolution.