3D Circle

Operator Function

Find edge points in the ROI; fit a 3D circle based on the found edge points.

Parameter Introduction

Input Parameters

Parameter	Range	Default Value	Description	Illustration
Input Image	0-8	0	IM number for image input

Calculation Parameters

Parameter	Range	Default Value	Description	Illustration
Use Region Parameters	true/false	false	If enabled, use region as input; if disabled, use input image as input
Region	2D Window/Box	Box	Manually select appropriate ROI region > Note: Ensure the ROI center point is inside the circle. Can bind to select existing ROI region. When input is an array, output is also an array
Force Horizontal Fit	true/false	false	Force horizontal fit means requiring the model's normal vector or main direction to be parallel to the horizontal plane when fitting planes or other geometric shapes, typically used to ensure the model is horizontal in certain application scenarios. When enabled, it will force correction from the red circle to the blue circle
Search Mode	Conical Point Search	Conical Point Search	Conical Point Search: Use the conical probe method to find edge points, controlling the probe angle to locate edge points in the point cloud
Probe Angle		45	Controlling the probe angle can affect the definition of edge points. Typically choose an appropriate angle range to ensure real edge points can be detected
Fitting Method	Ransac/Least Squares	Ransac	Ransac: Used to fit models from data, especially when there is noise or outliers in the data Least Squares: Fit models by minimizing the sum of squared errors, suitable for situations with small errors, concentrated data points, uniform edge point distribution, and little noise
Distance Threshold		0.02	Used to define the maximum distance between a point and the fitted model. Points beyond this distance are considered outliers and do not participate in fitting
Maximum Iterations		500	Used to set the maximum number of iterations for the RANSAC algorithm. Generally, more iterations result in more accurate fitting results, but computational cost also increases

Tip

For more detailed explanations of parameter types, please refer to Type Definitions

Result Display

Parameter	Range	Default Value	Description	Illustration
ROI Point Set	true/false	false	Only effective when Use Region Parameters is selected. Region point set selected by ROI box. If enabled, display in the image
Edge Points	true/false	false	Edge points. If enabled, display in the image
Circle	true/false	false	Fitted circle. If enabled, display in the image
Circle Center	true/false	false	Circle center. If enabled, display in the image
Radius	true/false	false	Radius. If enabled, display in the image

Output Parameters

Name	Type	Range	Description
Result	bool	true/false	true for success false for failure
Warning	bool	true/false	true indicates a warning false indicates no warning
Message	string		Output success, error, or warning messages. Empty if no error or warning.
Time	float		Operator execution time, unit: ms
edge_cloud_point	pointset		3D circle feature points When input is an array, output is also an array
circle	circle3d		Found 3D circle coordinates and direction When input is an array, output is also an array
Rradius Text	string		Radius value
Center Point 3D	point3d		Found 3D circle center point

Exception Troubleshooting

No.	Exception Information	Corresponding Parameter	Solution
1	Input value is {0t}, invalid region type	Region Type	Only window2d, box, pointset supported
2	Region point cloud is empty		1. Check if point cloud is empty 2. Check if ROI selects point cloud 3. Check if binding is empty
3	No plane found		Robustness content, rarely occurs
4	Not found		Adjust fitting parameters

Example Introduction

Engineering Design

1. Select the Load Point Cloud tool to load the required 3D point cloud image to IM0.

2. Select the 3D Circle tool.

Tool Usage

1. Select the input image for the operation. The image number must match the IM number where the image is located in the project.

2. Select the region type as Box, move the box to the position to be measured, enclosing the point cloud area to be tested.

Usage Tips

1. Use the ROI controller on the image window to drag or scale the box;
2. Directly modify the box's start or end point coordinates in the calculation parameters to adjust the box position and size;

3. Set the parameters.

4. Check the content you want to display in the result display section.

5. Click Test to check if the image window and parameters meet expectations.

6. If there are no issues, click Save. Run the operator in the run list, and then view the running results in the corresponding IM.