stbiwarp7p

Warp7p filter. Used:

• STB: stb.

Simple utility to apply 7+1 parameter distortion (k1, k2, k3, p1, p2, cx, cy, mc) to an image as per the equations here. Uses an iterative process to recalculate coordinates, or a pseudo-transformation without an iterative process. Uses bilinear interpolation.

Here this filter is implemented in a full-color version.

Usage

./stbiwarp7p [-h] [-k k1 k2 k3] [-p p1 p2] [-c cx cy] [-m mc] [-i] [-x max_iter] input-file output.png

-k k1 k2 k3 The radial distortion coefficient (current = 0.000 0.000 0.000 ). -p p1 p2 The trapezoidal distortion parameters (current = 0.000 0.000 ). -c cx cy The center (current = 0.50 0.50 ). -m mc The scale (current = 1.00 ). -i Сoordinate transformation direction (current = -1 ). -x max_iter The maximum iteration (current = 100 ). -h display this help and exit.

Params value:

• default: -k 0.0 0.0 0.0 -p 0.0 0.0 -c 0.5 0.5 -m 1.0
• for example: -k -0.4 0.0 0.0 -p -0.05 0.1 -c 0.5 0.5 -m 2.0

stb_image and stb_image_write by Sean Barrett and others is used to read and write images.

Installation

• Clone the repo or download the source git clone --recurse-submodules https://github.com/ImageProcessing-ElectronicPublications/stbiwarp7p
• Execute make
• Done. Either use the stbiwarp7p executable directly or copy it somewhere in your PATH.

Links

• STB: stb.