Imagery data sometimes uses just a limited range of the complete image bit depth to express its values. This is typically the case with images that have a large bit depth, such as HDR imagery. The range of possible values increases, and therefore also the likelihood that only a limited range of values is used. When those values get mapped to colors for visualization, the typical result is a dark or almost black image. To create a better image, you can include a raster normalization step.
Using the image processing API, you can programmatically apply normalization operations to your raster. An alternative approach is to rely on OGC SLD/SE styling and define a normalization style:
<FeatureTypeStyle xmlns="http://www.opengis.net/se" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/se http://schemas.opengis.net/se/1.1.0/FeatureStyle.xsd" version="1.1.0"> <Name>raster_normalization_style</Name> <Rule> <Name>raster_normalization_styling_rule</Name> <RasterSymbolizer> <ContrastEnhancement> <Normalize/> </ContrastEnhancement> </RasterSymbolizer> </Rule> </FeatureTypeStyle>
If you save the style in a
.sld file with the same file name as the raster data file, and store it next to that raster file in the same folder,
it will be picked up automatically when the raster data is opened in Lucy or Lucy Map Centric.
See Styling data with OGC SLD for more information on how to use and apply OGC SLD/SE styling.