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computerVision module

A module for computer vision, offering functionality from OpenCV. The browser version uses the UC Irvine and Intel OpenCV.js port, https://github.com/ucisysarch/opencvjs.

To run an example, please point your browser to: https://ptolemy.berkeley.edu/accessors/hosts/browser/demo/computerVision/computerVision.html

Face detection is now in a separate module. To try, please point your browser to: https://ptolemy.berkeley.edu/accessors/hosts/browser/demo/faceDetector/faceDetector.html

To run in CapeCode, please install OpenCV, then try $PTII/ptolemy/actor/lib/jjs/modules/faceDetector/demo/FaceDetector/FaceDetector.xml .

Functions

The following functions are implemented by this module:

• Filter(): Construct a new object to invoke various filters. The filters are:
  • Filter.blur(options): Blur the image, optionally passing in options.blurSize (1-25).
  • Filter.dilate(options): Dilate the image, optionally passing in options.erosionSize (0-21).
  • Filter.erode(options): Erode the image, optionally passing in options.erosionSize (0-21).
  • Filter.findContours(options): Find contours of an image, optionally passing in options.cannyThreshold (10-150).
  • Filter.findEdges(options): Find edges of an image, optionally passing in options.cannyThreshold (10-150).
  • Filter.gaussianBlur(options): Blur the image, optionally passing in options.blurSize (1-25).
  • Filter.histogram(): Create a histogram from the image showing red, green and blue content.
  • Filter.makeBGRA(): Convert image to blue, green, red, alpha colorspace.
  • Filter.makeGray(): Convert image to grayscale.
  • Filter.makeHSV(): Convert image to hue, saturation, value colorspace.
  • Filter.makeYUV(): Convert image to luminance, chroma colorspace.
  • Filter.mediaBlur(options): Blur the image, optionally passing in options.blurSize (1-25).
  • Filter.getResult(): Return the result image.
  • Filter.setOriginal(input): Set the original image, where input may be a path to a local image, or the image itself (not implemented yet).
• filters: A list of available filters.
• filter(image, transform, options, callback): Apply the given transform with any options to the given image and invoke callback() with the result image.

Filter uses the event emitter pattern common in JavaScript, emitting:

• ready: Emitted when an image has successfully loaded from the specified path in setInput(input).

Usage

Import the module:

   var cv = require('computerVision');

To obtain a list of filters:

   var filters = cv.filters;

Invoke a filter and handle the result. For example, in an accessor with an input image and output result, to run findEdges():

    var self = this;
    this.addInputHandler('input', function() {
        var image = this.get('input');
        var options = {};
        options.cannyThreshold = 20;

        cv.filter(image, 'findEdges', options, function(result) {
        	self.send('output', result);
        });
    });

Installing OpenCV

On Windows, please follow these instructions.

On Mac, OpenCV can be installed through MacPorts. I encountered problems with Homebrew.

From the command line:

   sudo port install opencv +java

This should install /opt/local/share/OpenCV/java/libopencv_java320.dylib

If you'd like to try installing through Homebrew, try this and if that doesn't work try this. This appeared to install OpenCV for me, but not to the folder that Ptolemy looks for, /opt/local/share/OpenCV/java. Try editing $PTII.org.ptolemy.opencv.OpenCVLoader.java to point to the installed folder.

Browser display

The browser version uses the ImageProcessingDisplay module to automatically set up before and after canvases.

See Also

• Accessor demo
• OpenCV API
• Javascript OpenCV.js

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