Fill Contour

This function block fills a selected contour area on an input image. Use it to mask out or keep regions defined by a contour — either filling the inside of the shape or keeping everything outside it.

📥 Inputs

• Image Any — Source image where the contour will be applied.

• Contour — List of contour points or a simple two-point rectangle definition.

📤 Outputs

• Output Image — Resulting image with the contour area filled or the inverse applied, depending on the control setting.

🕹️ Controls

• Fill Inside — Checkbox. When checked the area inside the provided contour is preserved (everything else removed). When unchecked the inverse is preserved (inside removed, outside kept).

🎯 Features

• Accepts both complex contours and a simple two-point rectangle definition for quick rectangular masks.

• Lets you choose whether to keep the inside or the outside of the contour.

• Produces a clean masked output suitable for further processing or visualization.

⚙️ Running mechanism

When executed the block reads the provided image and the contour points. If only two points are provided they are interpreted as opposite corners of a rectangle. The block then creates a mask from the contour and applies that mask to the input image, producing the filled/filtered result according to the Fill Inside selection.

📝 Usage instructions

1. Provide an image to Image Any.

2. Provide a contour to Contour (either a point list or two points for a rectangle).

3. Toggle Fill Inside depending on whether you want to keep the contour area or its complement.

4. Use the Output Image for visualization or feed it into downstream blocks.

💡 Tips and Tricks

• To obtain contour points from an image automatically, use Find Contour or Feature Detector before this block and feed the result into Contour.

• For quick manual selection of an area, pair with Image ROI Select or Image ROI Polygon to define the region and then use the resulting coordinates here.

• If you want to crop the filled area afterwards, connect the output to Get ROI or Contour to Image.

• For background removal workflows, combine Fill Contour with Apply Mask or Background Removal (RMBG-1.4) depending on your needs.

• Preview the result using Show Image to verify visually before further processing.

• Use Blur or Image Threshold before contour extraction to reduce noise and improve contour quality.

🛠️ Troubleshooting

• If nothing changes, confirm the Contour contains valid points. Two points are treated as a rectangle; more points define a polygon.

• If the filled area looks inverted, toggle the Fill Inside checkbox.

• If the result includes unexpected regions, try preprocessing with Image Threshold or Blur and re-extract the contour with Find Contour.