Common Parameters

Image dimensions

Figure A.1 shows the InfoPACK naming conventions as regards width, height, woffset and hoffset.

Figure A.1: InfoPACK naming conventions for image dimensions.

The Intensity Flag

Datasets for SAR images can be stored as either intensity or amplitude data. It is important that you know what type of data you are using. Many images are stored as amplitude since the speckle is less obtrusive when these images are displayed. InfoPACK routines assume by default that images are stored as amplitude. If they are not then the flag intensity=1 needs to be set in the function or script call in order to indicate the image is in fact intensity data.

In general InfoPACK routines work on intensity data. If a routine is given amplitude data it will typically convert the data to intensity data, process the data and then convert the data back to amplitude. It is always worth checking the individual function specifications for exact behaviour though. For example, colseg run on amplitude data will return the square root of regional intensity mean values but will not square root the regional intensity gamma order parameters since that would make them meaningless.

Memory Management Options

All command line InfoPACK scripts (with very few exceptions) perform file to file operations by splitting the ``infile'' into tiles of size tilesize. These tiles are are processed and then recombined into ``outfile''. An overlap is used to remove the effect of any joins. Note that the default tile sizes and overlaps may need altering to better reflect the sizes of the features of interest in the processing chain. For example, when aiming to produce large regions with texseg or when running segment on polarimetric images, tile and overlap sizes will typically need to be increased to avoid any tiling artifacts appearing in the final image. By processing files in this manner, arbitrarily large images can be processed entirely in RAM.
Due to the file to file action, it is not possible to create ``outfile'' with the same name as ``infile''.
The following parameters can be set to manage this process:


tilesize integer, default 128. A tilesize of 128 x 128 is used.


overlap integer, default 16. To prevent obvious joins between tiles, an overlap of 16 is used.


tmpdir directory, default "/tmp/" or ``C:/TEMP''. Intermediate results are written here.