Examples with SparseGradientSafe boofcv.struct.sparse.SparseGradientSafe used on opensource projects

Example 1 with SparseGradientSafe

use of boofcv.struct.sparse.SparseGradientSafe in project BoofCV by lessthanoptimal.

the class ImplSurfDescribeOps method naiveGradient.

/**
 * Simple algorithm for computing the gradient of a region.  Can handle image borders
 */
public static <T extends ImageGray<T>> void naiveGradient(T ii, double tl_x, double tl_y, double samplePeriod, int regionSize, double kernelSize, boolean useHaar, double[] derivX, double[] derivY) {
    SparseScaleGradient<T, ?> gg = SurfDescribeOps.createGradient(useHaar, (Class<T>) ii.getClass());
    gg.setWidth(kernelSize);
    gg.setImage(ii);
    SparseGradientSafe g = new SparseGradientSafe(gg);
    // add 0.5 to c_x and c_y to have it round when converted to an integer pixel
    // this is faster than the straight forward method
    tl_x += 0.5;
    tl_y += 0.5;
    int i = 0;
    for (int y = 0; y < regionSize; y++) {
        for (int x = 0; x < regionSize; x++, i++) {
            int xx = (int) (tl_x + x * samplePeriod);
            int yy = (int) (tl_y + y * samplePeriod);
            GradientValue deriv = g.compute(xx, yy);
            derivX[i] = deriv.getX();
            derivY[i] = deriv.getY();
        // System.out.printf("%2d %2d %2d %2d dx = %6.2f  dy = %6.2f\n",x,y,xx,yy,derivX[i],derivY[i]);
        }
    }
}

Example 2 with SparseGradientSafe

use of boofcv.struct.sparse.SparseGradientSafe in project BoofCV by lessthanoptimal.

the class TestSparseGradientSafe method checkMakeBorderSafe.

/**
 * Read in a border and see if it returns zeros
 */
@Test
public void checkMakeBorderSafe() {
    Dummy d = new Dummy();
    SparseImageGradient<GrayF32, GradientValue_F32> safe = new SparseGradientSafe<>(d);
    // read the border case
    GradientValue_F32 v = safe.compute(0, 0);
    assertTrue(v.x == 0);
    assertTrue(v.y == 0);
    // read inside and see if it has the expected results
    assertTrue(safe.compute(width / 2, height / 2) == null);
}