16.33. ipfind

The ipfind tool detects interest points (IPs) in images and writes them out to .vwip files. ASP is able to read these files to recover the IPs. These files can be visualized with stereo_gui (Section 16.64.10).

This tool is useful in testing out different IP detection settings and visualizing them (using the option --debug-image).

One can pass multiple input images to ipfind and they will be processed one after another.

This program works in conjunction with ipmatch (Section 16.34) to match interest points across images.


ipfind [options] <images>


ipfind image1.tif image2.tif image3.tif

This will write image1.vwip, image2.vwip, image3.vwip.

Command-line options for ipfind:

--interest-operator <sift|orb|OBALoG|LoG|Harris|IAGD (default: sift)>

Choose an interest point detector. SIFT and ORB are implemented in OpenCV. OBALoG is from [Jak10]. IAGD (Integral Auto Gain Detector) is a variant of OBALoG.

--descriptor-generator <sift|orb|sgrad|sgrad2|patch|pca (default: sift)>

Choose a descriptor generator. Some descriptors work only with certain interest point operators (for example, for ‘OBALoG’ use ‘sgrad’, ‘sgrad2’, ‘patch’, and ‘pca’).

--ip-per-image <integer>

Set the maximum number of IP to find in the whole image. If not specified, use instead the value of --ip-per-tile.

--ip-per-tile <integer (default: 250)>

Set the maximum number of IP to find in each tile. The tile size is set with --tile-size.

-g, --gain <float (default: 1)>

Increasing this number will increase the gain at which interest points are detected.


Turn off scale-invariant interest point detection. This option only searches for interest points in the first octave of the scale space. Harris and LoG only.


Turn off rotational invariance.


Normalize the input. Use for images that have non-standard values such as ISIS cube files.


Individually normalize each processing tile.

--nodata-radius <integer (default: 1)>

Don’t detect IP within this many pixels of image borders or nodata.

--output-folder <string>

Write output files to this location.

-d, --debug-image <0|1|2 (default: 0)>

Write out a low-resolution or full-resolution debug image with interest points on it if the value of this flag is respectively 1 or 2. The default (0) is to do nothing.

--print-ip <integer (default: 0)>

Print information for this many detected IP.


Save the interest points in an ASCII data format that is compatible with the Lowe-SIFT toolchain.

--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.


Tell GDAL to not create bigtiffs.

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

TIFF compression method.

-v, --version

Display the version of software.

-h, --help

Display this help message.