3D Inflection Point Detection

Operator Function

Displays the points with the maximum curvature within the threshold range of the curve in the point cloud area along the X or Y direction, which are called inflection points. Outputs the midpoints of these inflection points or the fitted line.

Parameter Introduction

Input Parameters

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

Calculation Parameters

Parameter	Range	Default Value	Description	Illustration
Region	2D Window/2D Circular Window/2D Polygon Window/Box/Cylinder Box/Rotated Box/Point Set (Binding Only)	Box	Manually select an appropriate ROI region Existing ROI regions can be selected via binding
Search Direction	X/Y	X	X: Search for inflection points along the X direction Y: Search for inflection points along the Y direction
Coordinate Spacing Threshold		0.100	If the search direction is X, points with a spacing less than the threshold in the Y direction are considered on the same curve along the X direction; if the search direction is Y, points with a spacing less than the threshold in the X direction are considered on the same curve along the Y direction.
Angle Limit			Minimum Angle: Set the minimum angle for a point to be recognized as an inflection point Maximum Angle: Set the maximum angle for a point to be recognized as an inflection point
Output Option	true/false	false
Output Type	Point/Line	Point	The Output Type needs to be set when the Output Option is enabled Point: Set the output as a point and push it to the register Line: Set the output as a line and push it to the register

Result Display

Parameter	Range	Default Value	Description	Illustration
Inflection Points	true/false	false	Found inflection points; if enabled, they will be displayed in the image
Center Points	true/false	false	Center points of inflection points; if enabled, they will be displayed in the image
Fitted Line	true/false	false	Fitted line of inflection points; if enabled, it will be displayed in the image
ROI Point Set	true/false	false	Only takes effect when the Use Region Parameter is selected. The point set of the ROI-selected region; if enabled, it will be displayed 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		Outputs success, error, or warning information; empty if there are no errors or warnings
Time	float		Operator execution time, unit: ms
point	point3d		Coordinate information of the inflection point

Tip

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

Troubleshooting

Serial Number	Error Message	Corresponding Parameter	Solution
1	Invalid angle limit parameter		Ensure the minimum angle is less than the maximum angle
2	The input region type is {0}, which is an invalid region type	Region Type	Select the region input type from 2D Window/2D Circular Window/2D Polygon Window/Box/Cylinder Box/Rotated Box/Point Set
3	Empty region		1. Check if the selection is empty 2. Check if the point set is empty
4	Empty input point cloud		Confirm if the IM contains valid points; if not, load the point cloud or switch to an IM with valid points
5	Invalid coordinate spacing threshold		Adjust the coordinate spacing threshold appropriately according to the point cloud spacing
6	No inflection points found		Appropriately increase the coordinate spacing threshold or angle range
7	The output type is {0}, which is an invalid output type	Geometric Type	Select the output type as either Point or Line
8	The number of vertices of the input polygon is less than 3, making it impossible to form a polygon		Add vertices to the 2D polygon window so that the number of vertices is at least three

Example Introduction

Project Design

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

2. Select the 3D Inflection Point tool and set different output types.

Tool Usage

1. Select the input image to be operated on; the image serial number must be consistent with the IM serial 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, and enclose the point cloud to be measured.

Usage Tips

1. Drag or scale the Box using the ROI controller on the image window;
2. Directly modify the start or end coordinates of the Box 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 column.

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

6. After confirming there are no issues, click Save, run the operator in the running list, and you can view the running result in the corresponding IM.