clmtrackr/src/mossefilter/mosseFilterResponses.js

Javascript library for precise tracking of facial features via Constrained Local Models

import mosse from 'mosse';

var mosseFilterResponses = function() {

	var filters = [];
	var responses = [];
	var num_Patches = 0;

	this.init = function(filter_input, numPatches, filterWidth, filterHeight) {
		// load filters, make fft ready

		for (var i = 0;i < numPatches;i++) {
			var temp = {};
			temp.width = filterWidth;
			temp.height = filterHeight;
			var filterLength = filterWidth*filterHeight;
			var flar_fi0 = new Float64Array(filterLength);
			var flar_fi1 = new Float64Array(filterLength);
			for (var j = 0;j < filterLength;j++) {
				flar_fi0[j] = filter_input[i][0][j];
				flar_fi1[j] = filter_input[i][1][j];
			}
			temp.real = flar_fi0;
			temp.imag = flar_fi1;
			filters[i] = new mosse.mosseFilter();
			filters[i].load(temp);
		}

		num_Patches = numPatches;
	}

	this.getResponses = function(patches) {
		for (var i = 0;i < num_Patches;i++) {
			responses[i] = filters[i].getResponse(patches[i]);
			//responses[i] = logisticResponse(responses[i]);
			responses[i] = normalizeFilterMatrix(responses[i]);
		}

		return responses;
	}

	var logisticResponse = function(response) {
		// create probability by doing logistic transformation
		var filter_size = response.length;
		for (var j = 0;j < filter_size;j++) {
			response[j] = 1.0/(1.0 + Math.exp(- (response[j]-1.0) ));
		}
		return response;
	}

	var normalizeFilterMatrix = function(response) {
		// normalize responses to lie within [0,1]
		var msize = response.length;
		var max = 0;
		var min = 1;

		for (var i = 0;i < msize;i++) {
			max = response[i] > max ? response[i] : max;
			min = response[i] < min ? response[i] : min;
		}
		var dist = max-min;

		if (dist == 0) {
			console.log('a patchresponse was monotone, causing normalization to fail. Leaving it unchanged.');
			response = response.map(function() {return 1});
		} else {
			for (var i = 0;i < msize;i++) {
				response[i] = (response[i]-min)/dist;
			}
		}

		return response;
	}
}

export default mosseFilterResponses;