Polygon Detection

Overview

Polygon Detection node identifies geometric shapes within color-thresholded regions and returns their contours, bounding boxes, and shape labels.

Use this node to detect specific geometric shapes — for example circles, rectangles, or pentagons — in scenes where the target objects have a consistent color and a known shape type. Configure Color Thresholds to isolate the relevant regions first, then set Shape to filter for the geometric forms you want.

Input

Input Image

image required

The image frame to analyze. Connect this to a camera or upstream image output.

Color Thresholds

array required

Color rules used to isolate regions before shape analysis. See Color Thresholds for configuration details.

Morphology

object required

Morphological operations to clean the thresholded mask before shape fitting. See Morphology for details.

Shape

array required

List of geometric shape types to detect. Only regions whose fitted polygon matches one of the listed types are included in the output.

Supported values:

• circle
• triangle
• square
• rectangle
• otherQuadrilaterals
• pentagon

Overlay Results

boolean required

Whether to draw detected polygon contours and labels on the output frame. See Overlay Results.

Overlay Alpha Mask

number required

Opacity of the filled region overlays. See Overlay Alpha Mask.

Output

Overlay Image

image

Output frame from the node. If overlays are enabled, each detected polygon is filled and labeled with its shape type.

Detected Count

integer

Number of matching shapes detected in the current frame.

Detected Polygons

array

Array of detection objects. Each object contains the contour boundary points, the bounding box, and the detected shape label.