Package boofcv.alg.filter.derivative

Class DerivativeLaplacian

java.lang.Object

boofcv.alg.filter.derivative.DerivativeLaplacian

public class DerivativeLaplacian
extends Object

The Laplacian is convolved across an image to find second derivative of the image. It is often a faster way to compute the intensity of an edge than first derivative algorithms.

 This implementation of the laplacian has a 3 by 3 kernel.

            partial^2 f     partial^2 f
 f(x,y) =   ~~~~~~~~~~~  +  ~~~~~~~~~~~
            partial x^2     partial x^2

          [ 0   1   0 ]
 kernel = [ 1  -4   1 ]
          [ 0   1   0 ]
 

This formulation is derived by using the [-1 1 0] and [0 -1 1] difference kernels for the image derivative. Alternative formulations can be found using other kernels.

DEVELOPER NOTE: This is still a strong candidate for further optimizations due to redundant array accesses.

Field Summary

Fields

Modifier and Type	Field	Description
static Kernel2D_F32	kernel_F32
static Kernel2D_S32	kernel_I32

Constructor Summary

Constructors

Constructor	Description
DerivativeLaplacian()

Method Summary

Modifier and Type	Method	Description
static void	process(GrayF32 orig, GrayF32 deriv, @Nullable ImageBorder_F32 border)	Computes the Laplacian of 'orig'.
static void	process(GrayU8 orig, GrayF32 deriv)	Computes Laplacian on an U8 image but outputs derivative in a F32 image.
static void	process(GrayU8 orig, GrayS16 deriv, @Nullable ImageBorder_S32<GrayU8> border)	Computes the Laplacian of input image.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

kernel_I32

public static Kernel2D_S32 kernel_I32

kernel_F32

public static Kernel2D_F32 kernel_F32

Constructor Details

DerivativeLaplacian

public DerivativeLaplacian()

Method Details

process

public static void process(GrayU8 orig,
 GrayS16 deriv,
 @Nullable
 @Nullable ImageBorder_S32<GrayU8> border)

Computes the Laplacian of input image.

Parameters:

orig - Input image. Not modified.

deriv - Where the Laplacian is written to. Modified.

process

public static void process(GrayU8 orig,
 GrayF32 deriv)

Computes Laplacian on an U8 image but outputs derivative in a F32 image. Removes a step when processing images for feature detection

process

public static void process(GrayF32 orig,
 GrayF32 deriv,
 @Nullable
 @Nullable ImageBorder_F32 border)

Computes the Laplacian of 'orig'.

Parameters:

orig - Input image. Not modified.

deriv - Where the Laplacian is written to. Modified.