Specifies the type of Wavelet filter to be used for Wavelet Discrete Transform.
Values:
| IG_JPEG2K_FILTER_AUTO | Automatically selects the best transform depending on image type. It selects irreversible transform for true color and grayscale images, and reversible transform for paletted images. |
| IG_JPEG2K_FILTER_REVERSIBLE | Indicates a reversible transform based on 5/3 filter. It is necessary to use this transform in order to save a lossless JPEG 2000 file. Other control parameters that affect the lossless saving are RATE_BYTES and QUALITY_LAYERS. |
| IG_JPEG2K_FILTER_IRREVERSIBLE | Indicates an irreversible transform based on Daubechies 9/7 filter. This transform is more efficient for saving lossy compressed images than the reversible one. The amount of loss and compression ratio are defined by RATE_BYTES and QUALITY_LAYERS control parameters. |
Remarks:
See the description of the WAVELET_FILTER control parameter (used by JPEG 2000 and JPX format filters).