Merge pull request #78 from qwzybug/otsu-threshold

No-argument thresold() using Otsu's method

Author: atduskgreg

src/gab/opencv/OpenCV.java

@@ -846,6 +846,17 @@ public void threshold(int threshold){
 		Imgproc.threshold(getCurrentMat(), getCurrentMat(), threshold, 255, Imgproc.THRESH_BINARY); 
 	}
 
+	/**
+	 * Apply a global threshold to the image. The threshold is determined by Otsu's method, which
+	 * attempts to divide the image at a threshold which minimizes the variance of pixels in the black
+	 * and white regions.
+	 *
+	 * See: https://en.wikipedia.org/wiki/Otsu's_method
+	 */
+	public void threshold() {
+		Imgproc.threshold(getCurrentMat(), getCurrentMat(), 0, 255, Imgproc.THRESH_BINARY | Imgproc.THRESH_OTSU); 
+	}
+	
 	/**
 	 * Apply an adaptive threshold to an image. Produces a binary image
 	 * with white pixels where the original image was above the threshold