node-opencv/lib/opencv.js

var Stream = require('stream').Stream
  , Buffers = require('buffers')
  , util = require('util')
  , path = require('path');

var cv = module.exports = require('./bindings');
var Matrix = cv.Matrix, VideoCapture = cv.VideoCapture,
    ImageStream, ImageDataStream, ObjectDetectionStream, VideoStream;


Matrix.prototype.detectObject = function(classifier, opts, cb){
  var face_cascade;
  opts = opts || {};
  cv._detectObjectClassifiers = cv._detectObjectClassifiers || {};

  if (!(face_cascade = cv._detectObjectClassifiers[classifier])){
    face_cascade = new cv.CascadeClassifier(classifier);
    cv._detectObjectClassifiers[classifier] = face_cascade;
  }

  face_cascade.detectMultiScale(this, cb, opts.scale, opts.neighbors
    , opts.min && opts.min[0], opts.min && opts.min[1]);
}


Matrix.prototype.inspect = function(){
  var size = (this.size()||[]).join('x');
  return "[ Matrix " + size + " ]";
}


ImageStream =
cv.ImageStream = function(){
  this.writable = true;
}
util.inherits(ImageStream, Stream);


ImageStream.prototype.write = function(buf){
  var self = this;
  cv.readImage(buf, function(err, matrix){
    if (err) return self.emit('error', err);
    self.emit('data', matrix);
  });
}


ImageDataStream =
cv.ImageDataStream = function(){
  this.data = Buffers([]);
  this.writable = true;
}
util.inherits(ImageDataStream, Stream);


ImageDataStream.prototype.write = function(buf){
  this.data.push(buf);
  return true;
}


ImageDataStream.prototype.end = function(b){
  var self = this;
  if (b) ImageStream.prototype.write.call(this, b);

  var buf = this.data.toBuffer();
  cv.readImage(buf, function(err, im){
    self.emit('load', im);
  });
}


ObjectDetectionStream =
cv.ObjectDetectionStream = function(cascade, opts){
  this.classifier = new cv.CascadeClassifier(cascade);
  this.opts = opts || {};
  this.readable = true;
  this.writable = true;
}
util.inherits(ObjectDetectionStream, Stream);


ObjectDetectionStream.prototype.write = function(m){
  var self = this;
  this.classifier.detectMultiScale(m, function(err, objs){
    if (err) throw err;
    self.emit('data', objs, m);
  }
  , this.opts.scale
  , this.opts.neighbors
  , this.opts.min && this.opts.min[0]
  , this.opts.min && this.opts.min[1]);
}


VideoStream =
cv.VideoStream = function(src){
  if (!(src instanceof VideoCapture)) src = new VideoCapture(src);
  this.video = src;
  this.readable = true;
  this.paused = false;
}
util.inherits(VideoStream, Stream);


VideoStream.prototype.read = function(){
  var self = this;
  var frame = function(){
    self.video.read(function(err, mat){
      if (err) return self.emit('error', err);
      self.emit('data', mat);
      if (!self.paused) process.nextTick(frame);
    })
  }

  frame();
}


VideoStream.prototype.pause = function(){
  this.paused = true;
}


VideoStream.prototype.resume = function(){
  this.paused = false;
  this.read();
}


VideoCapture.prototype.toStream = function(){
  return new VideoStream(this);
}


// Provide cascade data for faces etc.
cv.FACE_CASCADE = path.resolve(__dirname, '../data/haarcascade_frontalface_alt.xml')