This document summarizes the development of new ADPCM image compression techniques that provide higher compression ratios than existing DPCM techniques while maintaining similar or better radiometric performance. It describes existing DPCM compression used in previous missions, and then presents two new ADPCM techniques - ADPCM (10:6) and ADPCM-RA (10:5) - that use multiple adaptive quantizers and achieve compression ratios of 10:6 and 10:5 respectively. Simulation results show the new ADPCM techniques significantly improve radiometric performance over DPCM for a variety of image types, particularly for high contrast images. The new techniques also recover a large portion of pixel values losslessly.