icommand.vision
Class MotionDetectionEffect

java.lang.Object
  icommand.vision.VisionEffect
      icommand.vision.MotionDetectionEffect

All Implemented Interfaces:

javax.media.Codec, javax.media.Controls, javax.media.Effect, javax.media.PlugIn

public class MotionDetectionEffect
extends VisionEffect

Motion detection effect. The engine has two steps. First the input image and the reference image (which is the image from the previous frame) is compared. Whenever a pixel has changed consideribly (determined by the threshold variable) a internal black-white-red image is marked (at the same exact location where the change occured). Therefore in the first step, the internal black-white-red image is has lit up clusters in the space where a change has occured.

The next step is to eliminate these clusters that are too small, but still appeared in our black-white-red image. Only the big clusters are left (and are colored red). During this process we keep a track of couunt of the big clusters. If the count is greater than blob_threshold then the input frame is determined to have consideribly motion as to the previous frame.

Many of the ideas have been taken from

1. A Gnome Security Camera by Lawrance P. Glaister.
2. Digital Image Processing by Kenneth R. Castleman; ISBN 0-13-211467-4
3. Computer Graphics Principles and Practice by Foley, van Dam, Feiner, Hughes; ISBN 0-201-84840-6
4. Java Media Format Sample Programs (mainly the one dealing with building an Effect plugin)

Author:

: Konrad Rzeszutek Modified by Lawrie Griffiths to fit in with lejos vision system.

Field Summary

int	blob_threshold Our threshold for determinig if the input image has enough motion.
boolean	debug Turn debugging on.
int	OPTIMIZATION Optimization.
int	threshold The threshold for determing if the pixel at a certain location has changed consideribly.
int	THRESHOLD_INC By what value you should increment.
int	THRESHOLD_INIT The initial threshold setting.
int	THRESHOLD_MAX Maximum threshold setting.

Fields inherited from interface javax.media.PlugIn

BUFFER_PROCESSED_FAILED, BUFFER_PROCESSED_OK, INPUT_BUFFER_NOT_CONSUMED, OUTPUT_BUFFER_NOT_FILLED, PLUGIN_TERMINATED

Constructor Summary

MotionDetectionEffect()
Initialize the Motion effect plugin.

Method Summary

java.lang.Object[]	getControls() Getter for array on one control for adjusing motion threshold and setting debug.
java.lang.String	getName() get the name of the effect
int	process(javax.media.Buffer inBuffer, javax.media.Buffer outBuffer) Process the image, detecting motion in the regions

Methods inherited from class icommand.vision.VisionEffect

close, getControl, getSupportedInputFormats, getSupportedOutputFormats, open, reset, setInputFormat, setOutputFormat

Methods inherited from class java.lang.Object

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

Field Detail

OPTIMIZATION

public int OPTIMIZATION

Optimization. Anything above 0 turns it on. By default its disabled.

THRESHOLD_MAX

public int THRESHOLD_MAX

Maximum threshold setting. Setting the threshold above this means to get the motion detection to pass the frame you pretty much have to full the whole frame with lots of motions (ie: drop the camera)

THRESHOLD_INC

public int THRESHOLD_INC

By what value you should increment.

THRESHOLD_INIT

public int THRESHOLD_INIT

The initial threshold setting.

threshold

public int threshold

The threshold for determing if the pixel at a certain location has changed consideribly.

blob_threshold

public int blob_threshold

Our threshold for determinig if the input image has enough motion.

debug

public boolean debug

Turn debugging on. Slows down the effect but shows how motion detection effect works.

Constructor Detail

MotionDetectionEffect

public MotionDetectionEffect()

Initialize the Motion effect plugin.

Method Detail

process

public int process(javax.media.Buffer inBuffer,
                   javax.media.Buffer outBuffer)

Process the image, detecting motion in the regions

Parameters:

inBuffer - the input Buffer

outBuffer - the output Buffer

Returns:

BUFFER_PROCESSED_OK or BUFFER_PROCESSED_FAILED

getName

public java.lang.String getName()

get the name of the effect

Returns:

"Motion Detection Effect"

getControls

public java.lang.Object[] getControls()

Getter for array on one control for adjusing motion threshold and setting debug.

Specified by:

getControls in interface javax.media.Controls

Overrides:

getControls in class VisionEffect

Returns:

an array of one MotionDetectionControl