Next: Contour-Based Image Compression for Fast Real-Time Coding . ... We describe a lossless compression program developed for incorporation into the data acquisition system of a 16 CCD drift scan survey. ... Although numerous programs are available for the lossy compression of astronomical images (e.g., White & Percival 1994; Starck et al. 1996), much less work has been published on lossless compression, in particular for online applications (although see Veran & Wright 1994). ...