Image Acquisition tools (Reading Notes) programmed with the USB camera in the MATLAB environment)

(1) programming with USB camera in MATLAB environment

The image acquisition toolbox in MATLAB provides us with the necessary functions, and we can call them directly. It mainly introduces how to use the toolbox to program the USB2.0 camera.

Tag: USB camera MATLAB

 

The image acquisition toolbox in MATLAB provides us with the necessary functions, so we can call them directly. In this post, we will briefly introduce how to use this toolbox to program the USB2.0 camera.

 

Let's get down to the truth. But remember that you have to install a Pc camera to do the following. If you want to install a camera for the first time, you 'd better restart the PC. Otherwise, you may not be able to recognize the camera.

 

In the whole process, we need to do the following:

1. query the specific parameters of usb2.0camera (imaqhwinfo)

2. Create a video input object (videoinput)

3. Image preview and display (preview, stoppreview, closepreview, and image)

4. Get the video image (getsnapshot)

5. Get and set the image retrieval device (get and set)

6. disable a video object (delete)

 

Before getting started, I would like to explain the following terms in the Image Acquisition toolbox:

 

Image Acquisition devices, such as cameras and scanners

Image Acquisition adapter: The main purpose is to transmit information between devices through MATLAB and image retrieval.

ROI: region of interest-of-interest

 

Let's talk about a few common functions. Here we just describe their functions. For details about how to use the help system

Getselectedsource

Imaqfind

Isvalid

Peekdata

Getdata

Imaqmontage

Query the specific parameters of usb2.0camera

To program a camera, we must know its related parameters. Of course, we can query the merchant's manual, but it's not tiring.

 

The MATLAB Image Acquisition Toolbox provides imaqhwinfo () For me to obtain the hardware information from the installed image on the PC.

 

 

If no parameter is input, a struct is returned, which contains the adapter and Matlab-related version information in the system (this is usually used for the first time)

> Info = imaqhwinfo

 

Info =

 

Installedadaptors: {'coreco' 'winvideo'} % two adapters are installed on my PC.

MATLAB version: '7.6 (r2008a )'

Toolboxname: 'image acquisition toolbox'

Toolboxversion: '3. 1 (r2008a )'

Copy code

When a parameter is input, a struct containing the data of the specified adapter is returned.

> Win_info = imaqhwinfo ('winvideo') % let's take a look at the specific parameters of the second adapter.

 

Win_info =

 

Adaptordllname: [1x81 char] % absolute path of the adapter DLL file

Adaptordllversion: '3. 1 (r2008a) '% adapter DLL file version

Adaptorname: 'winvideo' % adapter name

Deviceids: {[1]} % device ID, which is frequently used.

Deviceinfo: [1x1 struct] % device information, which is mainly used to obtain parameters of the device.

 

For more information, see, which of the following information does this image obtain? ==================

 

> Win_info.deviceids

 

Ans =

 

[1]

 

> Dev_win_info = win_info.deviceinfo

 

Dev_win_info =

 

Defaultformat: 'rgb24 _ 320x240' % get the default format of the image

Devicefilesupported: 0

Devicename: 'usb Pc camera p227' % device name

DeviceID: 1% device number

Objectconstructor: 'videoinput ('winvideo', 1) '% object construction method, which is mostly the same

Supportedformats: {1x12 cell} % supported formats of the obtained images. Generally, there are many formats. The above defaultformat is only the default format.

 

% ======================================================== See the Image Acquisition Device Support the image format

 

> Dev_win_info.supportedformats % you can see that the camera on my PC supports the following 12 picture formats

 

Ans =

 

Columns 1 through 5

 

'I420 _ 160x120 ''i420 _ 176x144' 'i420 _ 320x240' 'i420 _ 352x288 ''i420 _ 640x2017'

 

Columns 6 through 9

 

'Rgb24 _ 1280x960' 'rgb24 _ 160x120 ''rgb24 _ 176x144' 'rgb24 _ 320x240'

 

Columns 10 through 12

 

'Rgb24 _ 352x288' 'rgb24 _ 640x0000' 'rgb24 _ 800x600'

Video preview, collection, and storage

(1) create a video input object

OBJ = videoinput (adaptorname, DeviceID, Format)

Adaptorname: the name of the adapter. You can use the imaqhwinfo function without parameters for the first time.

DeviceID: The device ID. You can use the imaqhwinfo function to obtain the device ID for the first time.

Format: video collection format, which can be obtained through supportedformats of deviceinfo. If this parameter is not specified, the default format is used.

> OBJ = videoinput ('winvideo', 1, 'rgb24 _ 320x240') % here we use the default video collection format

 

Summary of video input object using 'usb pccamera p227 '.

 

Acquisition source (s): input1 isavailable.

 

Acquisition parameters: 'input1' is the current selected source.

10 frames pertrigger using the selected source.

'Rgb24 _ 320x240' video data to be logged upon start.

Grabbing first ofevery 1 frame (s ).

Log Data to 'memory 'on trigger.

 

Trigger parameters: 1 'immediate' trigger (s) on start.

 

Status: Waiting for start.

0 frames acquiredsince starting.

0 frames availablefor getdata.

(2) open the video preview window.

Himage = Preview (OBJ, himage)

OBJ: video collection object

Himage: The handle corresponding to the video preview window. That is to say, you can preview the video in the specified handle object. This parameter can be left blank.

You can use the colsepreview and stoppreview functions to close and stop the preview window.

Vidres = get (OBJ, 'videoresolution ');

Nbands = get (OBJ, 'numberofbands ');

Figure () % specifies the figure displayed in the preview form

Axes () % specifies the coordinate system displayed in the preview window

Himage = image (zeros (vidres (2), vidres (1), nbands ));

Preview (OBJ, himage );

(3) image capture, display, and storage

% Frame is the matrix of H x W x B. H Image Height, specified by roiposition; W image width, specified by roiposition; B cable number, specified by numberofbands

Frame = getsnapshot (OBJ); % get a video frame

Imshow (FRAME); % displays the obtained Frame

Imwrite(frame,'snap.jpg ', 'jpg ');

 

 

(2)

MATLAB camera data collection

Www.diybl.com time: 2010-07-10 Author: Network Editor: huyang629 CLICK: 24 [comment]

1. query the specific parameters of usb2.0camera. Enter imaqinfo = imaqhwinfo Response Information Installedadaptors: {'winvideo '} MATLAB version: '7. 1 (r14sp3 )' Toolboxname: 'image acquisition toolbox' Toolboxversion: '1. 9 (r14sp3 )' Enter imaqinfo. installedadaptors Response Information Ans = 'Winvideo' Enter winvideoinfo = imaqhwinfo ('winvideo ') Response Information Winvideoinfo = Adaptordllname: [1x76 char] Adaptordllversion: '1. 9 (r14sp3 )' Adaptorname: 'winvideo' Deviceids: {[1]} Deviceinfo: [1x1 struct] Enter winvideoinfo. deviceinfo Response Information Ans = Defaultformat: 'yuy2 _ 160x120' Devicefilesupported: 0 Devicename: 'usb video device' DeviceID: 1 Objectconstructor: 'videoinput ('winvideo', 1 )' Supportedformats: {1X5 cell} Enter device1 = winvideoinfo. deviceinfo (1) Response Information Device1 = Defaultformat: 'yuy2 _ 160x120' Devicefilesupported: 0 Devicename: 'usb video device' DeviceID: 1 Objectconstructor: 'videoinput ('winvideo', 1 )' Supportedformats: {1X5 cell} Enter device1.devicename Response Information Ans = USB video device Enter device1.deviceid Response Information Ans = 1 Enter device1.defaultformat Response Information Ans = Yuy2_160x120 Enter device1.supportedformats Response Information Columns 1 through 4 'Yuy2 _ 160x120 ''yuy2 _ 176x144' 'yuy2 _ 320x240 ''yuy2 _ 352x288' Column 5 'Yuy2 _ 640x' 2. Enter the following code to obtain the default camera capture window for preview. OBJ = videoinput ('winvideo', 1 ); Preview (OBJ ); 3. Enter the following code: % Access an image acquisition device. Vidobj = videoinput ('winvideo', 1, 'yuy2 _ 640x '); Sources = vidobj. source; Whos sources Set (vidobj, 'selectedsourcename', 'input1 '); Sources Selectedsrc = getselectedsource (vidobj ); Get (selectedsrc ); Delete (vidobj ); Clear vidobj; Response Information Name size bytes class Sources 1x1 726 videosource object Grand total is 30 elements using 726 bytes Display summary for video source object: Index: sourcename: selected: 1 'input1' General settings: Parent = [1x1 videoinput] Selected = on Sourcename = input1 Tag = Type = videosource Device specific properties: Backlightcompensation = on Brightness =-16 Contrast = 120 Fig = 30.0000 Gamma = 60 Hue = 0 Saturation = 40 Sharpness = 3 4. Enter the following code: CLC; CLF; Clear all; Imaqmem (30000000); % applied for memory space % Adaptor: an interface between MATLAB and a video device. The main purpose is to transmit information. Vid = videoinput ('winvideo', 1, 'yuy2 _ 640x '); Preview (VID ); Start (VID ); H = figure ('numbertitle', 'off', 'name', 'video ',... 'Menubar ', 'none', 'color', 'C ',... 'Position', [0, 0, 1, 1], 'visible ', 'on'); % create a window Set (H, 'doublebuffer', 'on', 'outerposition', get (0, 'screensize ')); H1 = axes ('position', [0.02, 0.1, 0.4, 0.8], 'parent', H); % create a display window Hold on; Axis off; While ishandle (h) % determines whether an image object handle is valid A = getsnapshot (VID); % capture image Flushdata (VID); % clear all data of the Data retrieval engine, set the property samplesavailable to 0 Imshow (a); % display image Drawnow; % update images in real time End; Delete (VID );