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DetectCalibrationGrid_Circles

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Module: Calibration

Detects an arbitrary size symmetric circle pattern on the image.

Name Type Range Description
Input value
 inImage Image Input image
Input value
 inRoi Region* Range of pixels to be processed
Input value
 inCircleRadius Real 1.0 - Circle radius measured in input image pixels.
Input value
 inCircleDetectionThreshold Real 0.0 - Detection threshold (relative to local image patch).
Input value
 inCirclePolarity Polarity Circle intensity with respect to background.
Output value
 outImageGrid AnnotatedPoint2DArray Detected grid
Diagnostic input
 diagCirclesRegion Region Image after thresholding, this is the circle detector input.
Diagnostic input
 diagCircleCandidates Point2DArray Detected circle centers, before the grid construction step.

Requirements

For input inImage only pixel formats are supported: uint8.

Read more about pixel formats in Image documentation.

Hints

Circles may have holes. This can utilized, for example, for designating some specific coordinates on the calibration board. Note that the hole diameter must be less than a half of the circle diameter.

Examples

Description of usage of this filter can be found in examples and tutorial: Hand-Eye Calibration - On Filters.

Input image for DetectCalibrationGrid_Circles executed with inCircleRadius = 5

Detected calibration points

Remarks

The circle pattern must be a rectangular grid, with equal spacing in both dimensions.

Errors

This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

Error type Description
DomainError Not supported inImage pixel format.
DomainError Region of interest exceeds an input image.
DomainError Not supported inImage pixel format in DetectCalibrationGrid_Circles. Supported formats: UInt8.

Complexity Level

This filter is available on Advanced Complexity Level.

Filter Group

This filter is member of DetectCalibrationGrid filter group.

See Also