human/src/body/decodeMultiple.js

41 lines
2.2 KiB
JavaScript

import * as buildParts from './buildParts';
import * as decodePose from './decodePose';
import * as vectors from './vectors';
const kLocalMaximumRadius = 1;
function withinNmsRadiusOfCorrespondingPoint(poses, squaredNmsRadius, { x, y }, keypointId) {
return poses.some(({ keypoints }) => {
const correspondingKeypoint = keypoints[keypointId].position;
return vectors.squaredDistance(y, x, correspondingKeypoint.y, correspondingKeypoint.x) <= squaredNmsRadius;
});
}
function getInstanceScore(existingPoses, squaredNmsRadius, instanceKeypoints) {
const notOverlappedKeypointScores = instanceKeypoints.reduce((result, { position, score }, keypointId) => {
if (!withinNmsRadiusOfCorrespondingPoint(existingPoses, squaredNmsRadius, position, keypointId)) result += score;
return result;
}, 0.0);
return notOverlappedKeypointScores / instanceKeypoints.length;
}
function decodeMultiplePoses(scoresBuffer, offsetsBuffer, displacementsFwdBuffer, displacementsBwdBuffer, config) {
const poses = [];
const queue = buildParts.buildPartWithScoreQueue(config.body.scoreThreshold, kLocalMaximumRadius, scoresBuffer);
const squaredNmsRadius = config.body.nmsRadius ^ 2;
// Generate at most maxDetections object instances per image in decreasing root part score order.
while (poses.length < config.body.maxDetections && !queue.empty()) {
// The top element in the queue is the next root candidate.
const root = queue.dequeue();
// Part-based non-maximum suppression: We reject a root candidate if it is within a disk of `nmsRadius` pixels from the corresponding part of a previously detected instance.
const rootImageCoords = vectors.getImageCoords(root.part, config.body.outputStride, offsetsBuffer);
if (withinNmsRadiusOfCorrespondingPoint(poses, squaredNmsRadius, rootImageCoords, root.part.id)) continue;
// Else start a new detection instance at the position of the root.
const keypoints = decodePose.decodePose(root, scoresBuffer, offsetsBuffer, config.body.outputStride, displacementsFwdBuffer, displacementsBwdBuffer);
const score = getInstanceScore(poses, squaredNmsRadius, keypoints);
if (score > config.body.scoreThreshold) poses.push({ keypoints, score });
}
return poses;
}
exports.decodeMultiplePoses = decodeMultiplePoses;