GxMotdet

GxMotdet


Version 7.2.10

The GX motdet Control is a dedicated ActiveX control for detecting changes between stills in a stream.

The GX Motdet control is an image source and container control. If the GX motdet control connects to an image source control it updates the images from the source and analyzes them. The Threshold property of the GX Motdet control determines the result of the motion detection. If the max. difference between the sequential images is greater than Threshold then motion occurred. The control generate ImageUpdate event after every images and parameters determines the status of the motion detection.

Properties of the GxMotdet module

xsize

Width of a still (integer)
This property is must be set to the width of the images. The algorithm does not work with images that have different sizes.

ysize

Height of a still (integer)
This property is must be set to the height of the images. The algorithm does not work with images that have different sizes.

scale_x

Diminutive value in X orientation
It contains a diminutive value in the X orientation and must be a positive integer number. The default value is 8 (e.g.: If an image width is 640 pixels, the module diminutives it to 80 pixels). The less value results in better precision but the algorithm will be slower.

scale_y

Diminutive value in Y orientation
It contains a diminutive value in the Y orientation and must be a positive integer number. The default value is 8 (e.g.: If an image height is 480 pixels, the module diminutives it to 60 pixels). Lower values results in better precision but the algorithm will be slower.

block_x

Width of a block
Width of a block in pixels. It must be less than the diminutived width (xsize/scale_x). Lower value results in better precision and quick speed but it increases the probability of false hits.

block_y

Height of a block
Height of a block in pixels. It must be less than the diminutived height (ysize/scale_y). Lower value results in better precision and quick speed but it increases the probability of false hits.

contrast_min

Minimal pixel contrast
It defines the minimal contrast. The algorithm does not differentiate two pixels with the numerical difference within this interval. The default value is 8 (e.g.: If the value is 4 it signifies 4 in the 8-bit grayscale image /256 values/).

sensibility

Sensibility
The sensibility of the algorithm. If the overall pixel difference of a block greater than sensibility*block_x*block_y, the the block is added to the critical area.


Class Diagram

GxMotdet

Public:

Methods:

NameDescription
 ConnectThis method connects the control as an image container object to an image source object.  
 GetErrorThis method returns the error code and string of the control.  
 GetErrorCodeThis method returns the error code of the control.  
 GetErrorStringThis method returns the error string of the control.  
 GetImageSourceThis method returns a binary value representing the control's class as an image source.  
 GetIntPropertyThis method gets an integer property of the GxMotdet module.  
 GetSourceHandleThis method returns a binary value representing the control's object as a source handle.  
 SetIntPropertyThis method sets an integer property of the GxMotdetmodule.  
 UpdateImageThis method updates the image of the control by getting the image from the image source to which it is connected to.  

Events:

NameDescription
 ImageUpdateOccurs when the image of the ActiveX control is updated  

Private:

Properties:

NameDescription
 AutoUpdateImageEnables/disables the automatic image update from the connected source. 
 ImgSrcParamParameter string given for the image source control when updating the image.  
 ThresholdIf the max. difference between the sequential images is greater than Threshold then motion occurred. 
 Version[Read only] The version of the GxMotdet ActiveX control  
History