Java Doc for BoxFilterDescriptor.java in  » 6.0-JDK-Modules » Java-Advanced-Imaging » javax » media » jai » operator » Java Source Code / Java DocumentationJava Source Code and Java Documentation

The "BoxFilter" operation determines the intensity of a pixel in an image by averaging the source pixels within a rectangular area around the pixel. This is a special case of the convolution operation, in which each source pixel contributes the same weight to the destination pixel. The pixel values of the destination image are defined by the pseudocode:

 int count = width * height; // # of pixels in the box
 for (int b = 0; b < numBands; b++) {
 int total = 0;
 for (int j = -yKey; j < -yKey + height; j++) {
 for (int i = -xKey; i < -xKey + width; i++) {
 total += src[x+i][y+j][b];
 }
 }
 dst[x][y][b] = (total + count/2) / count; // round
 }
 

Convolution, like any neighborhood operation, leaves a band of pixels around the edges undefined. For example, for a 3x3 kernel only four kernel elements and four source pixels contribute to the convolution pixel at the corners of the source image. Pixels that do not allow the full kernel to be applied to the source are not included in the destination image. A "Border" operation may be used to add an appropriate border to the source image in order to avoid shrinkage of the image boundaries.

The kernel may not be bigger in any dimension than the image data.

Resource List

Name	Value
GlobalName	BoxFilter
LocalName	BoxFilter
Vendor	com.sun.media.jai
Description	Performs special case convolution where each source pixel contributes equally to the intensity of the destination pixel.
DocURL	http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/BoxFilterDescriptor.html
Version	1.0
arg0Desc	The width of the box.
arg1Desc	The height of the box.
arg2Desc	The X position of the key element.
arg3Desc	The Y position of the key element.

Parameter List

Name	Class Type	Default Value
width	java.lang.Integer	3
height	java.lang.Integer	width
xKey	java.lang.Integer	width/2
yKey	java.lang.Integer	height/2

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.create(StringParameterBlockRenderingHints) .
See Also:   JAI
See Also:   ParameterBlockJAI
See Also:   RenderedOp
Parameters:
  source0 - RenderedImage source 0.
Parameters:
  width - The width of the box.May be null.
Parameters:
  height - The height of the box.May be null.
Parameters:
  xKey - The X position of the key element.May be null.
Parameters:
  yKey - The Y position of the key element.May be null.
Parameters:
  hints - The RenderingHints to use.May be null.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.create(StringParameterBlockRenderingHints) .
See Also:   JAI
See Also:   ParameterBlockJAI
See Also:   RenderedOp
Parameters:
  source0 - RenderedImage source 0.
Parameters:
  width - The width of the box.May be null.
Parameters:
  height - The height of the box.May be null.
Parameters:
  xKey - The X position of the key element.May be null.
Parameters:
  yKey - The Y position of the key element.May be null.
Parameters:
  hints - The RenderingHints to use.May be null. The RenderedOp destination.
throws:
  IllegalArgumentException - if source0 is null.