human/src/face/facemesh.ts

/**
 * BlazeFace, FaceMesh & Iris model implementation
 *
 * Based on:
 * - [**MediaPipe BlazeFace**](https://drive.google.com/file/d/1f39lSzU5Oq-j_OXgS67KfN5wNsoeAZ4V/view)
 * - Facial Spacial Geometry: [**MediaPipe FaceMesh**](https://drive.google.com/file/d/1VFC_wIpw4O7xBOiTgUldl79d9LA-LsnA/view)
 * - Eye Iris Details: [**MediaPipe Iris**](https://drive.google.com/file/d/1bsWbokp9AklH2ANjCfmjqEzzxO1CNbMu/view)
 */

import { log, join, now } from '../util/util';
import * as tf from '../../dist/tfjs.esm.js';
import * as blazeface from './blazeface';
import * as util from './facemeshutil';
import * as coords from './facemeshcoords';
import * as iris from './iris';
import { histogramEqualization } from '../image/enhance';
import { env } from '../util/env';
import type { GraphModel, Tensor } from '../tfjs/types';
import type { FaceResult, Point } from '../result';
import type { Config } from '../config';

type BoxCache = { startPoint: Point, endPoint: Point, landmarks: Array<Point>, confidence: number };
let boxCache: Array<BoxCache> = [];
let model: GraphModel | null = null;
let inputSize = 0;
let skipped = Number.MAX_SAFE_INTEGER;
let lastTime = 0;
const enlargeFact = 1.6;

export async function predict(input: Tensor, config: Config): Promise<FaceResult[]> {
  // reset cached boxes

  const skipTime = (config.face.detector?.skipTime || 0) > (now() - lastTime);
  const skipFrame = skipped < (config.face.detector?.skipFrames || 0);
  if (!config.skipAllowed || !skipTime || !skipFrame || boxCache.length === 0) {
    const possibleBoxes = await blazeface.getBoxes(input, config); // get results from blazeface detector
    lastTime = now();
    boxCache = []; // empty cache
    for (const possible of possibleBoxes.boxes) { // extract data from detector
      const box: BoxCache = {
        startPoint: possible.box.startPoint,
        endPoint: possible.box.endPoint,
        landmarks: possible.landmarks,
        confidence: possible.confidence,
      };
      boxCache.push(util.squarifyBox(util.enlargeBox(util.scaleBoxCoordinates(box, possibleBoxes.scaleFactor), Math.sqrt(enlargeFact))));
    }
    skipped = 0;
  } else {
    skipped++;
  }
  const faces: Array<FaceResult> = [];
  const newCache: Array<BoxCache> = [];
  let id = 0;
  for (let i = 0; i < boxCache.length; i++) {
    let box = boxCache[i];
    let angle = 0;
    let rotationMatrix;
    const face: FaceResult = { // init face result
      id: id++,
      mesh: [],
      meshRaw: [],
      box: [0, 0, 0, 0],
      boxRaw: [0, 0, 0, 0],
      score: 0,
      boxScore: 0,
      faceScore: 0,
      annotations: {},
    };

    if (config.face.detector?.rotation && config.face.mesh?.enabled && env.kernels.includes('rotatewithoffset')) {
      [angle, rotationMatrix, face.tensor] = util.correctFaceRotation(box, input, inputSize);
    } else {
      rotationMatrix = util.fixedRotationMatrix;
      face.tensor = util.cutBoxFromImageAndResize(box, input, config.face.mesh?.enabled ? [inputSize, inputSize] : [blazeface.size(), blazeface.size()]);
    }
    if (config?.filter?.equalization) {
      const equilized = await histogramEqualization(face.tensor as Tensor);
      tf.dispose(face.tensor);
      face.tensor = equilized;
    }
    face.boxScore = Math.round(100 * box.confidence) / 100;
    if (!config.face.mesh?.enabled) { // mesh not enabled, return resuts from detector only
      face.box = util.getClampedBox(box, input);
      face.boxRaw = util.getRawBox(box, input);
      face.boxScore = Math.round(100 * box.confidence || 0) / 100;
      face.score = face.boxScore;
      face.mesh = box.landmarks.map((pt) => [
        ((box.startPoint[0] + box.endPoint[0])) / 2 + ((box.endPoint[0] + box.startPoint[0]) * pt[0] / blazeface.size()),
        ((box.startPoint[1] + box.endPoint[1])) / 2 + ((box.endPoint[1] + box.startPoint[1]) * pt[1] / blazeface.size()),
      ]);
      face.meshRaw = face.mesh.map((pt) => [pt[0] / (input.shape[2] || 0), pt[1] / (input.shape[1] || 0), (pt[2] || 0) / inputSize]);
      for (const key of Object.keys(coords.blazeFaceLandmarks)) face.annotations[key] = [face.mesh[coords.blazeFaceLandmarks[key] as number]]; // add annotations
    } else if (!model) { // mesh enabled, but not loaded
      if (config.debug) log('face mesh detection requested, but model is not loaded');
    } else { // mesh enabled
      const [contours, confidence, contourCoords] = model.execute(face.tensor as Tensor) as Array<Tensor>; // first returned tensor represents facial contours which are already included in the coordinates.
      const faceConfidence = await confidence.data();
      face.faceScore = Math.round(100 * faceConfidence[0]) / 100;
      const coordsReshaped = tf.reshape(contourCoords, [-1, 3]);
      let rawCoords = await coordsReshaped.array();
      tf.dispose([contourCoords, coordsReshaped, confidence, contours]);
      if (face.faceScore < (config.face.detector?.minConfidence || 1)) { // low confidence in detected mesh
        box.confidence = face.faceScore; // reset confidence of cached box
      } else {
        if (config.face.iris?.enabled) rawCoords = await iris.augmentIris(rawCoords, face.tensor, config, inputSize); // augment results with iris
        face.mesh = util.transformRawCoords(rawCoords, box, angle, rotationMatrix, inputSize); // get processed mesh
        face.meshRaw = face.mesh.map((pt) => [pt[0] / (input.shape[2] || 0), pt[1] / (input.shape[1] || 0), (pt[2] || 0) / inputSize]);
        for (const key of Object.keys(coords.meshAnnotations)) face.annotations[key] = coords.meshAnnotations[key].map((index) => face.mesh[index]); // add annotations
        box = util.squarifyBox(util.enlargeBox(util.calculateLandmarksBoundingBox(face.mesh), enlargeFact)); // redefine box with mesh calculated one
        face.box = util.getClampedBox(box, input); // update detected box with box around the face mesh
        face.boxRaw = util.getRawBox(box, input);
        face.score = face.faceScore;
        newCache.push(box);

        // other modules prefer different crop for a face so we dispose it and do it again
        /*
        tf.dispose(face.tensor);
        face.tensor = config.face.detector?.rotation && config.face.mesh?.enabled && env.kernels.includes('rotatewithoffset')
          ? face.tensor = util.correctFaceRotation(util.enlargeBox(box, Math.sqrt(enlargeFact)), input, inputSize)[2]
          : face.tensor = util.cutBoxFromImageAndResize(util.enlargeBox(box, Math.sqrt(enlargeFact)), input, [inputSize, inputSize]);
        */
      }
    }
    faces.push(face);
  }
  boxCache = [...newCache]; // reset cache
  return faces;
}

export async function load(config: Config): Promise<GraphModel> {
  if (env.initial) model = null;
  if (!model) {
    model = await tf.loadGraphModel(join(config.modelBasePath, config.face.mesh?.modelPath || '')) as unknown as GraphModel;
    if (!model || !model['modelUrl']) log('load model failed:', config.face.mesh?.modelPath);
    else if (config.debug) log('load model:', model['modelUrl']);
  } else if (config.debug) log('cached model:', model['modelUrl']);
  inputSize = model.inputs[0].shape ? model.inputs[0].shape[2] : 0;
  if (inputSize === -1) inputSize = 64;
  return model;
}

export const triangulation = coords.TRI468;
export const uvmap = coords.UV468;