Turn Photos into Cartoons with Python, OpenCV, and Flask

The article describes a Python project that converts portrait photos into cartoon‑style images using OpenCV and serves the result through a minimal Flask web page.

Difference between photos and cartoons

Cartoons emphasize clear outlines and use fewer colors, making them less detailed than real photos.

Step 1: Reduce colors

Using OpenCV, the image is first downsampled with a pyramid to lower resolution, then bilateral filtering is applied repeatedly to blur the image while preserving edges.

Downsampling reduces resolution by a factor of 4; the input image size must be a multiple of 4 to avoid mismatched dimensions after up‑sampling.

Step 2: Enhance outlines

Adaptive thresholding extracts strong edges, which are combined with the blurred image via a bitwise‑and operation to produce a cartoon‑like outline.

Step 3: Flask web interface

A minimal Flask app provides an upload page; after selecting an image, the server runs the cartoon conversion and returns the cartoon image URL, which the HTML page displays.

The current UI is basic and can be further styled.