Locked within the numerical values that make up a calibrated CCD image is a staggering amount of information. To access it, we use a series of software tools— routines crafted to extract the specific types of information that astronomers want from images. These fall into three categories:
• information about pixels,
• information about the entire image, and
• information about regions of interest.
Pixel information consists of location and pixel value—the address and telephone number for each individual speck in an image.
Information about the entire image is like a survey of all the people in a community—it's about pixel demographics.
The pixels in a region of interest are related, like people in a family. A pixel family might be a star image; the information the family shares is the star's brightness and position.
In this chapter, you will learn what the standard image measurement tools are, what they measure, and what you can do with that information. Much of the material might seem at first dry and statistical; but as you learn more, you will begin to understand and interpret information about individual pixels, their communities, and their families.
Was this article helpful?