16.23. disparitydebug

The disparitydebug program produces visualizable images from disparity maps created with parallel_stereo and stereo. These are named D_sub.tif, D.tif, RD.tif, and F.tif (see Section 19 for what each is).

The disparity map files can be useful for debugging because they contain raw disparity values as measured by the correlator; however they cannot be directly visualized or opened in a conventional image browser. The disparitydebug tool converts a single disparity map file into two normalized TIFF image files (*-H.tif and *-V.tif, containing the horizontal and vertical, or line and sample, components of disparity, respectively) that can be viewed using any image display program, including with the stereo_gui tool shipped with ASP (Section 16.71).

The disparitydebug program will also print out the range of disparity values in a disparity map, that can serve as useful summary statistics when tuning the search range settings in the stereo.default file (Section 14.4.2).

If the input images are map-projected (georeferenced), the outputs of disparitydebug will also be georeferenced.

16.23.1. Examples

disparitydebug run/run-D_sub.tif

View the obtained horizontal and vertical disparities with:

stereo_gui run/run-D_sub-H.tif run/run-D_sub-V.tif

Another example of using this tool (and a figure) is given in Section 6.1.8, when discussing how to examine a produced run.

16.23.2. Raw disparity extraction

To extract the horizontal and vertical bands from a disparity without normalization, run a command such as:

disparitydebug --raw run/run-F.tif

Invalid values are set to a no-data value (-1e+6) that is saved in the geoheader of the output files.

This option is available in build 1/2026 and later.

16.23.3. Command-line options

-o, --output-prefix <string (default: “”)>

Specify the output file prefix. This is set automatically if not provided.

--raw

Save the raw disparity values without any normalization. Invalid pixels are set to no-data.

--save-norm

Save the norm of the disparity instead of its two bands.

--save-norm-diff

Save the maximum of norms of differences between a disparity and its four neighbors.

--normalization <(integer integer integer integer) (default = auto)>

Normalization range. Specify in the format: hmin vmin hmax vmax.

--roi <(integer integer integer integer) (default = auto)>

Region of interest. Specify in the format: xmin ymin xmax ymax.

-t, --output-filetype <string (default: tif)>

Specify the output file type.

--threads <integer (default: 0)>

Select the number of threads to use for each process. If 0, use the value in ~/.vwrc.

--cache-size-mb <integer (default = 1024)>

Set the system cache size, in MB.

--tile-size <integer (default: 256 256)>

Image tile size used for multi-threaded processing.

--no-bigtiff

Tell GDAL to not create BigTiff files.

--tif-compress <None|LZW|Deflate|Packbits (default: LZW)>

TIFF compression method.

-v, --version

Display the version of software.

-h, --help

Display this help message.