/**
    * This source code file is part of a direct port of Stan Birchfield's implementation
    * of a Kanade-Lucas-Tomasi feature tracker. The original implementation can be found
    * here: http://www.ces.clemson.edu/~stb/klt/
    *
    * As per the original code, the source code is in the public domain, available
    * for both commercial and non-commercial use.
    */
   package org.openimaj.video.tracking.klt;
  
  import org.openimaj.image.FImage;
  import org.openimaj.image.processing.convolution.FGaussianConvolve;
  
  /**
   * A common set of objects, namely the gaussian pyramid for an image and the gradients of each
   * level of the pyramid
   * @author Sina Samangooei (ss@ecs.soton.ac.uk)
   *
   */
  public class PyramidSet{
  	/**
  	 * @param image
  	 * @param tc
  	 */
  	public PyramidSet(FImage image, TrackingContext tc) {
  		int nrows = image.height, ncols = image.width;
  		FImage floatimg2 = image.process(new FGaussianConvolve(tc.computeSmoothSigma()));
  		this.imgPyr = new Pyramid(ncols, nrows, (int) tc.subsampling, tc.nPyramidLevels);
  		this.imgPyr.computePyramid(floatimg2, tc.pyramid_sigma_fact);
  		this.gradx = new Pyramid(ncols, nrows, (int) tc.subsampling, tc.nPyramidLevels);
  		this.grady = new Pyramid(ncols, nrows, (int) tc.subsampling, tc.nPyramidLevels);
  		for (int i = 0 ; i < tc.nPyramidLevels ; i++)
  			tc.computeGradients(imgPyr.img[i], tc.grad_sigma, gradx.img[i], grady.img[i]);
  	}
  	/**
  	 * @param imgPyr
  	 * @param gradx
  	 * @param grady
  	 */
  	public PyramidSet(Pyramid imgPyr, Pyramid gradx,Pyramid grady) {
  		this.imgPyr = imgPyr;
  		this.gradx = gradx;
  		this.grady = grady;
  	}
  	PyramidSet() {
  		// TODO Auto-generated constructor stub
  	}
  	/**
  	 * the image pyramid
  	 */
  	public Pyramid imgPyr;
  	/**
  	 * the x gradient pyramid
  	 */
  	public Pyramid gradx;
  	/**
  	 * the y gradient pyramid
  	 */
  	public Pyramid grady;
  	
  	/**
  	 * @return true if the pyramid is null
  	 */
  	public boolean isNull() {
  		return imgPyr == null || grady == null || gradx == null;
  	}
  }