mesobot-calib

Calibration process for the Mesobot. Written using OpenCV 3.4.1

Usage

To use the application, run its executable from the command line.

Example:

./stereo_calib -l calib/left -r calib/right -w 9 -h 6 -length 0.0225 -thresh 1.4 -check

Output

The calibration information and settings will be placed into calib_settings.yml. Maps for OpenCV's remap function will be placed into undistort_maps.yml.

Options

There are a variety of options available for the calibration process. Of them, only -l, -r, -w, -h, -length, and -thresh are required for the program to function.

Required

-l Specifies the folder containing the left images.

-r Specifies the folder containing the right images.

-w Specifies the width of the chessboard pattern (inner corners).

-h Specifies the height of the chessboard pattern (inner corners).

-length Specifies the side edge of a square on the chessboard pattern (in meters).

-target Specifies the target overall error of the calibration. If left blank, program will target and error of 0.

-thresh Specifies the threshold value scalar. This value will be multiplied by the average overall reprojection error to eliminate image pairs with a maximum individual (either image's) error above the scaled threshold.

Solution methods

-lu Enables Gaussian elimination solution method (very fast).

-qr Enables QR decomposition solution method (faster than normal).

Stereo calibration models

These models can be used alone or in conjunction with each other. They specify which distortion coefficients will be enabled in the stereo calibration process.

-rational Enables the rational model, adding the radial distortion coefficients k4, k5, and k6.

-thinprism Enables the thin prism model, adding the thin prism distortion coefficients s1, s2, s3, and s4.

-tilted Enables the tilted model, adding the tilt distortion coefficients tauX and tauY.

Stereo calibration parameters [more info]

-k1 to -k6 Fixes the corresponding radial distortion coefficient during calibration.

-s Fixes the thin prism disortion coefficients (use only with -thinprism).

-tau Fixes the tilt distortion coefficients (use only with -tilted).

-fixar Fixes the aspect ratio.

-fixp Fixes the principal points during the optimization.

-fixtan Fixes the tangential disortion coefficients.

-zerotan Fixes the tangential distortion coefficients to 0.

-fixf Fixes the focal lengths.

-samef Enforces equal focal lengths for the cameras.

Chessboard pattern detection parameters [more info]

-at Enables adaptive thresholding.

-ni Enables image normalization.

-fq Enables filtering out of false quads extracted at the contour retrieval stage.

-check Checks images quickly for a chessboard pattern before intensive search. Can save time during chessboard detection.