FITS BMP and SCR Image Formats and the Transformations

In this paper, the image formats-FITS, BMP and SCR-are introduced in detail. The FITS format has become a universal format in astronomy and can be supported by almost all the software parckages in astronomical uses. Meanwhile the BMP format is widely used on personal computers and is supported by a large amount of PC softwares in displaying, progressing and printing. The SCR format is used in the Yannan Observatory to implement CCD image collection on PCs. Therefore, it is important to realize the transformation among the three formats so that CCD images can be processed on PCs and work-station freely. The transformation includes images head and image data, and the critical part is to transform the high and low bits of the data.