> For the complete documentation index, see [llms.txt](https://docs.augelab.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.augelab.com/function-blocks/blocks-reference/detections-shapes/shape-analysis/minimum-circle.md). # Minimum Circle This function block finds and draws the smallest enclosing circle around a provided shape (contour) and returns the circle's center and radius along with a visual result image. It is useful for estimating object size, position, or for simple shape-based measurements. ## 📥 Inputs `Image Any`\ The image used as the drawing surface and visual reference for the result. A copy of this image will be returned with the detected circle overlaid. `Contour`\ A shape (contour) that defines the object to enclose. This typically comes from a contour detection or shape-extraction block. ## 📤 Outputs `Image`\ A copy of the input image with the minimum enclosing circle drawn on it. `Center`\ The center position of the enclosing circle (x, y). Use this value for alignment, measurements, or further geometric operations. `Radius`\ The radius of the enclosing circle. Useful for size estimation, thresholds, or triggering downstream logic. ## 🕹️ Controls This block has no interactive controls—just provide the required input sockets and it will produce the outputs when run. ## ⚙️ Running mechanism When the block runs it accepts a contour and an image. It computes the smallest circle that fully encloses the contour, draws that circle onto a copy of the provided image, and outputs the annotated image together with the circle's center and radius. The block expects a valid contour input; if no contour is provided, the result will be empty or unchanged. ## 🎯 Features * Produces a visual result image with the enclosing circle drawn for easy verification. * Returns numeric geometric outputs (`Center`, `Radius`) that can be used by downstream blocks for measurement or logic. * Lightweight and fast—suitable for real-time pipelines when contours are available. * Works with any contour-producing block; no additional parameters are required. ## 📝 Usage 1. Provide a contour to the `Contour` input — typically the result from a contour detector or shape extractor. 2. Provide an image to the `Image Any` input for visualization. 3. Run the scenario; the block will output the annotated image and the circle properties. ## 💡 Tips and Tricks * To obtain contours, use the `Find Contour` or `Find Object` blocks before this block. * If the contour is irregular or too detailed, use `Approximate Contour` to simplify the shape before feeding it into this block — this can produce a more meaningful enclosing circle for noisy contours. * Crop to a region of interest with `Image ROI Select` or `Image ROI` to speed up processing and avoid unrelated contours. * Preprocess the image with `Blur` or `Image Threshold` to improve contour detection quality upstream. * Visualize or annotate final results using `Draw Rectangle`, `Draw Result On Image`, or send the result to `Show Image` for a larger viewer window. * Use the numeric outputs (`Center`, `Radius`) with measurement or logic blocks (for example to compare sizes, to trigger alerts, or to store values). ## 🛠️ Troubleshooting * No circle appears: ensure a valid contour is provided. Use a contour-producing block such as `Find Contour` and verify the contour is not empty. * Circle seems too large or too small: try simplifying the contour with `Approximate Contour` or refine contour detection by adjusting upstream preprocessing (e.g., `Image Threshold`, `Blur`). * Unexpected results on noisy images: crop the area of interest with `Image ROI Select` and filter noise first.