Pixels to a centroid
A small editable mask with its area, centroid and bounding box computed live. It is the smallest complete example of turning pixels into a measurement, which is what every region descriptor does at scale.
Try this
Add a few stray pixels far from the blob and watch the centroid drift toward them. That is why noise removal comes before measurement.
Try it: locate the ball
Where this lab comes from
Image processing, computer vision, and computer graphics: one picture, three directions of the arrowThree fields, one shared object: the digital image. Graphics turns a model into an image (forward), vision turns an image into a model (inverse), and image processing turns an image into a better image. Worked on a single red-ball scene, with a 1957→2026 timeline of how they split apart and re-merged.
More in the image itself
- One colour per photosite — Throw away two thirds of the colour, then guess it back.
- Hitting the colour a meter measured — Drag the gains and watch ΔE against 22 metered patches.
- Sixteen by twelve real pixels — Hover a pixel, read its index and its three numbers.