The method is best suited for images of text. Clean images are compressed better than noisy images. Images scanned with a more uniform scanning apparatus are compressed better than those scanned on a poor scanner. Originals compress better than high-generation photocopies. Unlike Group 4, however, the method displays the following characteristics.
Longer documents show higher compression ratios than shorter ones.
Higher resolution documents allow for increasingly better compression. Nonetheless, even with these characteristics in mind, the performance of Cartesian compression on this same photograph image that was problematic for Group 4 shows that the method is at least broad enough to encompass photographs well. The Cartesian method achieves more than a five-fold improvement in compression over the Group 4 method for this image, as shown in Table 7. The reconstructed image demonstrates that the Cartesian method does not degrade the image quality of the original at all. The system requires no special hardware and only one megabyte of memory.