A small JavaScript library for detecting faces using the PICO algorithm with the face rotation invariant implementation.
An example of using the basic functions of the library:
// load cascade
fetch('./data/classifier.dat')
.then(function(response) {
if (!response.ok) throw Error(response.statusText || 'Request error');
return response.arrayBuffer();
})
.then(function(cascade) {
// create face detector with options
return PicoFace(cascade, {
shiftfactor: 0.1, // move the detection window by 10% of its size
scalefactor: 1.1, // resize the detection window by 10% when moving to the higher scale
initialsize: 0.1, // minimum size of a face (10% of image area)
rotation: [0, 30, 330], // rotation angles in degrees
threshold: 0.2, // overlap threshold
memory: 3 // number of images in the memory
});
})
.then(function(detect) {
// image = ImageData
return detect(image);
})
.then(function(dets) {
// dets = [{ r: rows, c: cols, s: size, q: quality, a: angle }]
console.log(dets);
});All parameters of the library are set in the constructor, here is their description:
| Parameter | Default | Description |
|---|---|---|
| shiftfactor | 0.1 | Sliding window movement step as a percentage (10%) of the image size |
| scalefactor | 1.1 | Sliding window resizing step as a percentage (10%) of image size |
| initialsize | 0.1 | Initial size of the sliding window as a percentage (10%) of the image size |
| threshold | 0.2 | Percentage (20%) of intersections of found candidates for grouping them into one area |
| rotation | [0] | Array of rotation angles to be searched (0 to 360 in 1 degree increments) |
| memory | 1 | Number of images (frames) in memory to improve detection quality |
The output is an array of areas where the algorithm assumes there are faces. Here is a description of this area:
| Feature | Description |
|---|---|
| c | X-coordinate of the center of the found face area |
| r | Y-coordinate of the center of the found face area |
| s | Size of found area (width and height or diameter) |
| q | Detection quality (higher is better quality) |
| a | Rotation angle of the image (the most likely one listed in the rotation parameter) |
Build the library bundle in the directory ./dist/:
npm install
npm run build
Start the demo webserver:
npm run dev
- PICO: https://github.com/nenadmarkus/pico
- picojs: https://github.com/tehnokv/picojs
- tracking.js: https://github.com/eduardolundgren/tracking.js