>元々は [[DSE:http://dse.ssi.ist.hokudai.ac.jp/]] の wiki にあったコンテンツです。



* What's CameraAgentPlugIn ? [#k70975b8]

CameraAgentPlugIn suit provides an abstract layer (functions) to access various kinds of camera and capture devices (such as USB Camera[WDM or VfW], ViewRanger[HTTP and JPEG decoder]). 
So you can use such devices via a DLL of this suit.

YES, NO NEED to make long long and too complicated codes like an use of DirectShow API.

Your task is so simple : make an instance of CameraAgentPlugIn class and call only a few methods.

Is the name of this suits curious ?
It has long history but i can't describe it in english orz.

* ARCHITECTURE [#g9115a27]


This suit is part of an architecture in a diagram above.

Your software is "Applications" in the diagram, and it connects via "Direct DLL Manipulation".

* HOW TO USE [#xff44e3a]

This is fragment code of ConsoleExample.cpp .

Firstly, you specify the include operation at the top of your source.

 #include "CameraAgentPlugIn.h"

In "main" function, you'll make an instance of CameraAgentPlugIn class and manipulate it.
 // make an instance of CameraAgentPlugIn
 CameraAgentPlugIn capi;

Call "Open" and "OnInit" method to open and initialize the dll.
After calling "OnInit" method, you can retrieve the device information from a member-variable named strDeviceName_.

 // Call "Open" method to open dll. you can change dll filename as you need the type of device
 if( !capi.Open( "WdmReader.dll" ) ) {
 	printf( "cannot open DLL : %s\n", capi.strDllFilename_.c_str() );
 	return -1;
 // Call "OnInit" method to initialize dll, an argument is HWND of parent window. 
 // some type of dll (mainly "VfwReader.dll") has to be supplid the parent window handle.
 // but almost DLLs don't need HWND, you specify it as NULL simply.
 if( !capi.OnInit( NULL ) ) {
 	printf( "fault to initialize DLL\n" );
 	return -1;
 // device(DLL) info.
 printf( "DLL:%s\n", capi.strDeviceName_.c_str() );

If your application needs specific resolution, you have to set the resolution by calling "SetResolution" method. If not, the resolution of the captured image is a default value of dll or device; all WDM-type device has the default resolution suitable for its porposes or spec.

 // set/get resolution (if you need)
 capi.SetResolution( 640, 480 );
 long width = 0, height = 0;
 capi.GetResolution( &width, &height );

Call "Capture" method to get the image of device.

The captured image is an instance of KImageRGB class.
KImageRGB is supporting class for imaging operations; get width/height of image, color of pixel, raw buffer pointer of the image.

 // capturing
 KImageRGB image;
 if( !capi.Capture( image ) ) {
 	printf( "fault capturing...\n" );
 	return -1;

Here is the sample code of KImageRGB class but it's useful i thought.
Make brightness histogram of image.
It's pretty simple.

 // make brightness histogram ( N_DIV is a number of class )
 #define	N_DIV	8
 int np[N_DIV] = {0};
 int y = 0;
 for( y=0; y<image.height; y++ ) {
 	for( int x=0; x<image.width; x++ ) {
 		K_RGB p = image.pixel(x,y);
 		// calc. histogram
 		int g = (p.r+p.g+p.b)/3;
 		for( int i=0; i<N_DIV; i++ ) {
 			int lower_bound = 256*i/N_DIV;
 			int upper_bound = 256*(i+1)/N_DIV;
 			if( lower_bound <= g && g < upper_bound ) {
 				np[i] ++;
 				continue;	// exactly, you don't need this. 
 // show histogram
 int n = 0, i = 0;
 for( i=0; i<N_DIV; i++ ) n += np[i];
 for( i=0; i<N_DIV; i++ ) {
 	int lower_bound = 256*i/N_DIV;
 	int upper_bound = 256*(i+1)/N_DIV;
 	printf( "%3d-%3d:%6d: ", lower_bound, upper_bound-1, np[i] );
 	int x = np[i]*70/n;
 	for( int i=0; i<x; i++ ) putchar( '*' );
 	printf( "\n" );

KImageRGB class has a function to save the image to bitmap file.
Simply calling "save_to_bitmap" method by specifing a filename of bitmap file.
 // save (if you need)
 if( !image.save_to_bitmap( "capture.bmp" ) )
 	printf( "fault to write bitmap...\n" );

* REFERENCE [#p6cd6f3a]

- see [[./Reference]]

* SEE ALSO [#u5d77aaf]

- [[研究/カメラエージェント君]]

* AUTHOR [#mb3c321b]

- TAKEUCHI Hiroaki
- DSE Camera Mission Unit

* CHANGE LOG [#xbe801ba]

- 2005/09/27
-- wrote chapter "What's CameraAgentPlugIn ?", "ARCHITECTURE", "REFERENCE"
- 2005/09/29
-- wrote chapter "HOW TO USE"
-- create a new page for "REFERENCE"

* Free Talk [#gc71ff70]





こういう説明書的な文書は .h ファイルとか Readme.txt に書くとバージョン管理ができない(だって最新版がどこにあるのか不明でしょ?)んで,Wiki に書くのが現実的な解だと思う.



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