bowling-analysis-system/src/bowling_analysis/metrics/calculations/angles/LowerBodyAngles.js

A comprehensive system for analyzing bowling techniques using video processing and metrics calculation

/**
 * @module metrics/calculations/angles/LowerBodyAngles
 * @description Functions for calculating lower body joint angles
 */

const { calculateAngleBetweenVectors, getSafeLandmark, createVector } = require('../MetricsUtilities');

/**
 * Calculate knee flexions for both sides
 * @param {Array} landmarks - Array of pose landmarks
 * @returns {Object} Left and right knee flexions
 */
function calculateKneeFlexions(landmarks) {
  return {
    left: calculateLeftKneeFlexion(landmarks),
    right: calculateRightKneeFlexion(landmarks)
  };
}

/**
 * Calculate ankle flexions for both sides
 * @param {Array} landmarks - Array of pose landmarks
 * @returns {Object} Left and right ankle flexions
 */
function calculateAnkleFlexions(landmarks) {
  return {
    left: calculateLeftAnkleFlexion(landmarks),
    right: calculateRightAnkleFlexion(landmarks)
  };
}

/**
 * Calculate hip flexions for both sides
 * @param {Array} landmarks - Array of pose landmarks
 * @returns {Object} Left and right hip flexions
 */
function calculateHipFlexions(landmarks) {
  return {
    left: calculateLeftHipFlexion(landmarks),
    right: calculateRightHipFlexion(landmarks)
  };
}

/**
 * Calculate hip rotations for both sides
 * @param {Array} landmarks - Array of pose landmarks
 * @returns {Object} Left and right hip rotations
 */
function calculateHipRotations(landmarks) {
  return {
    left: calculateLeftHipRotation(landmarks),
    right: calculateRightHipRotation(landmarks)
  };
}

// Individual calculation functions
function calculateRightKneeFlexion(landmarks) {
  const hip = getSafeLandmark(landmarks, 24);
  const knee = getSafeLandmark(landmarks, 26);
  const ankle = getSafeLandmark(landmarks, 28);
  
  if (!hip || !knee || !ankle) return null;
  
  const thigh = createVector(hip, knee);
  const shin = createVector(knee, ankle);
  
  return 180 - calculateAngleBetweenVectors(thigh, shin);
}

function calculateLeftKneeFlexion(landmarks) {
  const hip = getSafeLandmark(landmarks, 23);
  const knee = getSafeLandmark(landmarks, 25);
  const ankle = getSafeLandmark(landmarks, 27);
  
  if (!hip || !knee || !ankle) return null;
  
  const thigh = createVector(hip, knee);
  const shin = createVector(knee, ankle);
  
  return 180 - calculateAngleBetweenVectors(thigh, shin);
}

function calculateRightAnkleFlexion(landmarks) {
  const knee = getSafeLandmark(landmarks, 26);
  const ankle = getSafeLandmark(landmarks, 28);
  const foot = getSafeLandmark(landmarks, 32);
  
  if (!knee || !ankle || !foot) return null;
  
  const shin = createVector(knee, ankle);
  const footVector = createVector(ankle, foot);
  
  return calculateAngleBetweenVectors(shin, footVector);
}

function calculateLeftAnkleFlexion(landmarks) {
  const knee = getSafeLandmark(landmarks, 25);
  const ankle = getSafeLandmark(landmarks, 27);
  const foot = getSafeLandmark(landmarks, 31);
  
  if (!knee || !ankle || !foot) return null;
  
  const shin = createVector(knee, ankle);
  const footVector = createVector(ankle, foot);
  
  return calculateAngleBetweenVectors(shin, footVector);
}

function calculateRightHipFlexion(landmarks) {
  const shoulder = getSafeLandmark(landmarks, 12);
  const hip = getSafeLandmark(landmarks, 24);
  const knee = getSafeLandmark(landmarks, 26);
  
  if (!shoulder || !hip || !knee) return null;
  
  const trunk = createVector(hip, shoulder);
  const thigh = createVector(hip, knee);
  
  return calculateAngleBetweenVectors(trunk, thigh);
}

function calculateLeftHipFlexion(landmarks) {
  const shoulder = getSafeLandmark(landmarks, 11);
  const hip = getSafeLandmark(landmarks, 23);
  const knee = getSafeLandmark(landmarks, 25);
  
  if (!shoulder || !hip || !knee) return null;
  
  const trunk = createVector(hip, shoulder);
  const thigh = createVector(hip, knee);
  
  return calculateAngleBetweenVectors(trunk, thigh);
}

function calculateRightHipRotation(landmarks) {
  const leftHip = getSafeLandmark(landmarks, 23);
  const rightHip = getSafeLandmark(landmarks, 24);
  const rightKnee = getSafeLandmark(landmarks, 26);
  
  if (!leftHip || !rightHip || !rightKnee) return null;
  
  const hipLine = createVector(leftHip, rightHip);
  const thigh = createVector(rightHip, rightKnee);
  
  const thighHorizontal = {
    x: thigh.x,
    y: 0,
    z: thigh.z
  };
  
  return calculateAngleBetweenVectors(hipLine, thighHorizontal);
}

function calculateLeftHipRotation(landmarks) {
  const leftHip = getSafeLandmark(landmarks, 23);
  const rightHip = getSafeLandmark(landmarks, 24);
  const leftKnee = getSafeLandmark(landmarks, 25);
  
  if (!leftHip || !rightHip || !leftKnee) return null;
  
  const hipLine = createVector(rightHip, leftHip);
  const thigh = createVector(leftHip, leftKnee);
  
  const thighHorizontal = {
    x: thigh.x,
    y: 0,
    z: thigh.z
  };
  
  return calculateAngleBetweenVectors(hipLine, thighHorizontal);
}

module.exports = {
  calculateKneeFlexions,
  calculateAnkleFlexions,
  calculateHipFlexions,
  calculateHipRotations
};