Webcam Imaging and Image Processing

Abstract

If you are shooting the Sun at high magnification, the sharpness of the image you get with a conventional digital camera (compact or DSLR) will be dependent on the steadiness of the seeing at the moment the shutter was released. Even in good seeing, when the image is relatively steady visually, close-ups of sunspots and other solar features can be disappointing because they were taken when atmospheric turbulence affected the image. You can counter this problem, to some extent, by shooting a large number of images with your digital camera in the hope of getting at least one image taken in a brief instant of steady seeing. The large capacity of modern memory cards makes shooting large numbers of images eminently possible, and indeed is an excellent way of getting good images at long focal lengths using eyepiece projection with a DSLR. But the most effective solution is to shoot a “movie,” perhaps a minute long and composed of hundreds or even thousands of digital images, and then select the sharpest images in the computer later, stacking as many of them as possible to create a super-sharp final image. This can be achieved using a device that in recent years has caused a revolution in the quality of amateur images of the Sun, Moon and planets—the webcam.