Kazuyuki Kobayashi, Hosei Univ.

VCAPG2 for MATLAB Now! Source code is available from here.(2007.Aug.1)

Summary:

VCAPG2 is DirectShow based video capture DLL that support various types of video capture cards.

Keywords:

vcapg,usb,frame,grabber,IEEE1394,Vfw,directshow,video

Screenshot of two camera grabbing images under MATLAB.

One camera is connected to Omni-directional camera, the other is normal camera.

you can see preview screen at left side of window. The bottom of left side of short menu describes video mode short menu. Depending on video capture device you may change following video mode.

TV Tuner

Second Crossbar

Video Crossbar

Video Capture Pin

Video Capture Filter

Video Source

Video Display

Video Format

Description:

VCAPG2 is a new version of MATLAB resident video capture program, which employs Microsoft's DirectShow libraries rather than the older Video for Windows (VfW) library.

In order to run VCAPG2, you will need to install the DirectX runtime libraries.

The vcapg2 requires a video capture device, such as a USB camera to be installed and working properly.

This code has been developed and tested with DirectX 8.1 and 9.0 with MATLAB6.1/6.5.

Features are

1. Up to 6 video capture cards can grab images at one command.(I tested one and two video capture cards)

2. Supported video capture devices are including IEEE1394 based DV CAM, USB Camera as well as old VFW based Camera.(I tested DV-CAM, USB Camera, VFW based Camera)

3. VCAPG2 can run up to almost twice as fast as VfW based program such as VCAPG [1] which is available both source and binary code from http://www.ikko.k.hosei.ac.jp/~matlab/matkatuyo/

that I published.

Plaforms:

2000/XP

(NOTE: 95/98/ME are not supported!! Please use vcapg)

MATLAB Version:

6.1 or later

How to Install:(2003/03/07)

Just copy vcapg2.dll to your MATLAB current directory.

(You can check MATLAB current directory by usiing 'pwd' command.)

After that you just type 'vcapg2' will appear preview window.

Notes:

Supported default capture color mode only RGB 16bit. However depending on video capture card, you may change different color modes by clicking task tray icon.

VCAPG2 is a MATLAB residents program; you can confirm residents or not left bottom side of task tray icon. From task tray icon, you can change video mode and crossbar and/or TV tuner mode, which are depending on installed video capture cards.

If you want to remove VCAPG2 from MATLAB, type clear all.

Sample scripts:

%%%%%%%%%

%sample script for One video capture card is installed.

%Initialization mode

clear all;

cardnum=vcapg2; % you will get available video capture devices number usually 1

% capture mode

aa=vcapg2;% grabbing camera image.

imshow(aa);

clear all; % remove

%%%%%%%%%

%sample script for Two camera capture cards are installed

clear all;

%Initialization mode

cardnum=vcapg2; % you will get available video capture devices number usually 2

% capture mode

[aa,bb]=vcapg2;% grabbing camera image.

subplot(1,2,1);imshow(aa);subplot(1,2,2);imshow(bb);

%%%%%%%%%

%sample script for Two camera capture cards are installed

% if you have two video capture card, you can choose video card at initialization mode

clear all;

cardnum=vcapg2(1); % you can set 0 or 1

% capture mode

aa=vcapg2;% grabbing camera image.

imshow(aa);

%%%%%%%%%

%sample script for One video capture card is installed.

% realtime image processing example just process diff at Red image

%Initialization mode

clear all;

cardnum=vcapg2; % you will get available video capture devices number usually 1

close all;figure(1);set(1,'doublebuffer','on');

% capture mode

for i=1:100

aa=vcapg2;% grabbing camera image.

subplot(2,1,1);imshow(aa);subplot(2,1,2);imshow(diff(double(aa(:,:,1)),[]);

drawnow;% this is important to view realtime.

end

clear all; % remove

Difference between VCAPG and VCAPG2:

	VCAPG	VCAPG２
Library	Video For Windows API	COM based DirectShow library
Multiple camera support	not available due to specification of VfW	Up to 6 cameras. we test up to 2 cameras.
Type of frame grabbing device	VfW	DirectShow,VfW including (IEEE1394 DvCam, USB Camera)
Captured color mode	Depending on frame grabber 1,4,8,16,24,32bitRGB is supported	Depending on frame grabber default color mode is 16BitRGB.
Speed of grabbing images (Depending on hardware and color mode)	About 23sec/100 frame	About 15 sec / 100 frame
Supported OS	95/98/ME/2000/XP	2000/XP

By using GraphEdit (which is bundled with DirectX SDK), you can see connection of video capture cards.

This is example of DV-camera preview screen and GraphEdit view.

If you want to change DV resolution or quality, you can do from GraphEdit property like following.

Update Information:(2003/02/07)

Preview window setting can change at initialization time.

Difference from previous version is initialization option. Default preview interval set to 300msec.

Usage: Only works under initialization time

vcapg2(Board Num,Preview interval)

Board Num: 0,1,2,3 ,[ ] means default mode

Preview inerval: 1 to 65536[mSec],0 means no preview image mode

Usage examples:

clear vcapg2;vcapg2([ ],0); % multiple camera image grabbing mode with no preview window

clear vcapg2;vcapg2([ ],300); % multiple camera image grabbing mode with preview window at 300 mSec refresh rate.

Also you can specify video capture device number if available.

clear vcapg2;vcapg2(0,0); % board No. 0 camera image grabbing mode with no preview image

clear vcapg2;vcapg2(1,100); % board No. 1 camera image grabbing mode with preview window at 100mSec refresh rate.

Both Binary code and Source code is available from here:(2007/08/01)

Binary DLL can be available from
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=2939&objectType=file

Trouble shooting:(2003/03/07)

I made this utility based on amcap.cpp.

Please check by using amcap.exe, which is bundled with DirectX SDK.

If you have experienced similar problem, problem may be due to windows or capture driver.

You may be better to reinstall windows or capture driver.

Multiple-camera problem:(2003/03/07)

In order to work multiple-camera mode, DirectShow based video capture drivers are required.

1. The vcapg2 cannot handle the combination of several VfW based video capture board, since VfW based driver did not support multiple camera mode.

2. Some USB based video capture driver cannot work more than two cards, because of limitation of the USB bandwidth.

3. Please check by using GraphEdit to see the schematic diagram of video capture block. If you cannot see video capture block, probably the video capture driver didn’t support Directshow.

Video resolution problem:(2003/03/07)

1. Several VfW based video board cannot change the resolution from vcapg2, please change the default resolution by using video board bundled software or amcap before starting vcapg2.

2. In order to change resolution of IEEE1394 based camera resolution; please use to change GraphEdit, which is bundled with DirectX SDK.

3. Please check by using vcapg, which is available in http://www.ikko.k.hosei.ac.jp/~matlab/matkatuyo/.

Rights to use, citation:

Author may encourage to maintenance and consuming time to develop this utility, please cite the following reference in your paper or academic research.

Kazuyuki Kobayashi,"MATLAB Utilization Book", Shuwa System Co, Ltd., 2001,ISBN 4-7980-0141-4

For further update information browse to:

http://www.ikko.k.hosei.ac.jp/~matlab/matkatuyo/vcapg2.htm

References:

[1] Kazuyuki Kobayashi,"MATLAB Utilization Book", Shuwa System Co, Ltd., 2001,ISBN 4-7980-0141-4 (Japanese)

[2] Michael Linetsky, "Programming Microsoft Directshow", Wordware,ISBN: 1556228554

[3] DirectX 8.1 SDK amcap.cpp

[4] http://vision.kuee.kyoto-u.ac.jp/~hiroaki/firewire/directshow.html (Japanese)

[5] http://wwwdoi.elec.nara-k.ac.jp/html/jisyu/dxm/ds10.html (Japanese)

[] Last modified[]

[]
Last modified[]