Line Scan Distortion Correction Tool Overview

All images contain some distortion, for example, caused by imperfections in camera lenses. In many applications, the distortion does not affect the operation of vision tools, but for applications requiring high accuracy or applications with high distortion, it must be corrected to achieve the desired results.

The Line Scan Distortion Correction tool can measure and correct for nonlinear distortion (for example, lens distortion) in line scan image acquisition systems.

The Line Scan Distortion Correction tool analyzes the pattern in a training image and estimates the distortion.

The Line Scan Distortion Correction tool resamples each row of a run-time source image according to the measured distortion or to a user-provided set of sample positions to generate an undistorted run-time destination image. It resamples the entire field of view in a uniform physical fashion.

The figure below shows the type of distortion that this tool can correct.

Distorted and corrected image

The key differences between calibration tools described in section Calibration Tools and the Line Scan Distortion Correction tool are the following:

The Line Scan Distortion Correction tool uses a simple training target that is placed at a fixed position in front of the camera (calibration tools require that a calibration plate be moved relative to the camera).
The Line Scan Distortion Correction tool does not perform any calibration; no calibrated space is added to the image coordinate space tree (calibration tools compute a calibrated physical coordinate space and add it to the image's coordinate space tree).
The Line Scan Distortion Correction tool does not rectify distortion caused by a camera that is rotated; it can only correct nonlinear optical and perspective distortion (calibration tools do rectify the image skew caused by a rotated camera).
The Line Scan Distortion Correction tool estimates 3rd order polynomial to characterize the distortion map.

In general, you should use calibration tools, as they provide the most accurate distortion correction and they provide calibration in addition to distortion correction. The Line Scan Distortion Correction tool is intended to be used in applications where it is impossible to use a moving calibration plate.