If the defaults do not meet your application requirements, you can try to improve your compression ratio using the following techniques. We recommend trying these techniques in the order they appear.
Note that during development and at runtime, compression support is reliant upon the presence of a compression/decompression package license. This license is only included by default with the development dongle for the full version of MIL. In other cases, this license must be purchased separately.
Regardless of the type of your compression operation, you should first remove extraneous noise from the image (if possible) using MIL processing functions.
For JPEG lossy compression:
Allocate a YUV buffer for compression.
Increase the quantization factor using MbufControl() with M_Q_FACTOR.
Decrease the restart interval.
Change the quantization table (see the Working with tables section later in this chapter).
Change the Huffman table (see the Working with tables section later in this chapter).
For JPEG lossless compression:
Try the other supported predictors using MbufControl() with M_PREDICTOR.
Decrease the restart interval.
For JPEG2000 lossy compression:
Allocate a YUV buffer for compression.
Increase the quantization factor using MbufControl() with M_Q_FACTOR.
Decrease the target size using MbufControl() with M_TARGET_SIZE.
Change the number of decomposition levels of the DWT using with M_DECOMPOSITION_LEVEL.
Change the quantization table (see the Working with tables section later in this chapter).
For JPEG2000 lossless compression:
Change the number of decomposition levels of the DWT using MbufControl() with M_DECOMPOSITION_LEVEL.