Save Image Enhancements Tutorial

This tutorial outlines how to save image enhancements in CATALYST Professional.

Images can be enhanced at several levels, from standard enhancements that filter images to fully customized enhancements using lookup tables (LUTs) and histograms. Unenhanced image files are often difficult to interpret visually when they are opened in an image viewer. Enhancements make imagery clearer and easier to interpret.

When you open an image file in CATALYST Professional, it is enhanced automatically in the view pane based on the default enhancement. You can then create further custom enhancements, which are applied only in system memory. If you want to reuse or export the enhanced image, you must first save it.

There are two methods for saving enhancements: Using the Save As method, which is TIF-friendly, and editing the LUTs, which must be done in PIX format.

1. Using the Save As utility

By default, Focus applies an enhancement to images (Tools > Options > Layer > Default Visual Enhancement). You can export the enhanced image to a GeoTIFF file in Focus using "Save As" - after you have enhanced the image in Focus, right click raster file on MAPS tab and choose "Save as"; under the Properties for each image channel, select 8-bit unsigned (if scaling is required) & VISUAL scaling - this will scale the image and permanently apply the enhancement in a single step (Note: You will need to turn off the default enhancement in Focus to view the resulting GeoTIFF file properly).

Note: You can perform a similar procedure using the CATALYST Python API, as well. You would need to create the lookup table LUT segments for each channel using an algorithm like FUN (for example, using adaptive enhancement) or STR (for example, exponent of 0.5 = root; 1.0 =linear stretch), then apply the LUTs to the imagery using the LUT algorithm.

To save an enhancement using Save As:

1. In CATALYST Focus, apply the desired enhancements.
2. Under the Maps tab, right-click the raster file, select Save As. The Save As utility opens.
3. Next to each image layer, select Properties. Choose 8-bit unsigned and VISUAL scaling. The LUT is applied using this procedure.
4. Name the file and location for the new file.

2. Editing the look-up tables (LUTs)

Another way to permanently apply an enhancement to an image in Focus is to load a PIX image in the Focus viewer, apply an enhancement, and then edit the LUT of an image. You can then apply the LUT to a new image layer using the Algorithm Librarian LUT program.

Note: You should always create a new output layer to preserve the original data.

To edit the LUTs:

1. Load a PIX image in Focus (Note: Make sure to do this process with the PIX file. TIFF files do not support LUTs. No descriptive data is extracted from the TIFF file, nor is any written back).
2. Apply the desired enhancements.
3. Under the Maps tab, right click on the PIX file and choose Enhance > Edit LUTS.
4. Click on RED/GREEN/BLUE histogram - Save > SAVE Image with LUT - new layer (this burns the LUT into new image layer) OR Save LUT (this saves the lookup table to a LUT segment in the PIX file).
5. You can then apply the LUT to the image layer using the Algorithm Librarian LUT program. Note: Make sure to create a new output layer to preserve the original data.
6. When viewing the file again in the future, remember to turn off the default visual enhancement in Focus (Click on the Enhancements Tool, select None).