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ECWIMG: Importing ECW raster to IMG or JPEG format
Access this help text as a web page: ECWIMG
Presentation and options
The ECW (Enhanced Compressed Wavelet) files are highly compressed raster files thanks to the use of wavelet transforms. Typically, this compression is a lossy compression (also called non-conservative or degradable) (like the JPEG format) and, therefore, the quality is inferior (perhaps imperceptibly) in relation to the data from which has been originated. As a counterpart, it is the type of compression that most strongly compresses an image; In spite of this non-conservative character, the images usually have a visual aspect very similar to the original ones, unless they have been generated with extremely high compression levels; this is an important difference from the conventional JPEG format, which begins to present visual artifacts at lower compression levels.
This application allows to obtain the information of the internal metadata of the ECW format, import an ECW to a JPEG format (gray or RGB, depending on the ECW file) or extract between one and three IMG bands of an ECW.
In the case of importing to JPEG files, the conversion may become impossible if in this format the converted image occupies more than 2 Gbyte.
ECWIMG 0:
Displays the internal metadata saved in the ECW file.
ECWIMG 1:
Generates 1 JPEG file from an ECW image.
ECWIMG 2:
Generates 1 IMG file using a ECW grey file.
ECWIMG 3:
Generates 3 IMG files from a 24-bit ECW file.
Dialog box of the application
Syntax
Syntax:
- ECWIMG 0 ECWFileName
- ECWIMG 1 ECWFileName JPEGFileName [/QUALITAT]
- ECWIMG 2 ECWFileName IMGFileName
- ECWIMG 3 ECWFileName IMGFileName_R IMGFileName_G IMGFileName_B
Options:
- 0:
Displays the internal metadata saved in the ECW file.
- 1:
Generates 1 JPEG file from an ECW image.
- 2:
Generates 1 IMG file using a ECW grey file.
- 3:
Generates 3 IMG files from a 24-bit ECW file.
Parameters:
- ECWFileName
(ECW File Name -
Input parameter): Is the name of the ECW file.
- JPEGFileName
(JPEG File Name -
Output parameter): Is the name of the JPEG file resulting from the transformation.
- IMGFileName
(IMG File Name -
Output parameter): Is the name of the IMG file resulting from the transformation for ECW of a single spectral band (grey).
- IMGFileName_R
(IMG Red File Name -
Output parameter): Is the name of the Red IMG file resulting from the transformation of each RGB triplet band.
- IMGFileName_G
(IMG Green File Name -
Output parameter): Is the name of the Green IMG file resulting from the transformation of each RGB triplet band.
- IMGFileName_B
(IMG Blue File Name -
Output parameter): Is the name of the Blue IMG file resulting from the transformation of each RGB triplet band.
Modifiers:
/QUALITAT=
(Compression quality)
Compression quality in a range [0,100], where [5,95] is the useful range although in many cases it is advisable to enter a value between 70 and 75 (default is 75). Low values indicate very poor quality but a lot of compression. (Input parameter)
