problem acquiring the video from webcam
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hi every one .i am trying to acquire the video frames using the following codes .
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
a = imaqhwinfo;
[camera_name, camera_id, format] = getCameraInfo(a);
vid = videoinput(camera_name, camera_id, format);
% Set the properties of the video object
set(vid, 'FramesPerTrigger', Inf);
set(vid, 'ReturnedColorspace', 'rgb')
vid.FrameGrabInterval = 5;
%start the video aquisition here
start(vid)
while(vid.FramesAcquired<=200)
data = getsnapshot(vid);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%the camera info routine is as follows
function [camera_name, camera_id, resolution] = getCameraInfo(a)
camera_name = char(a.InstalledAdaptors(end));
camera_info = imaqhwinfo(camera_name);
camera_id = camera_info.DeviceInfo.DeviceID(end);
resolution = char(camera_info.DeviceInfo.SupportedFormats(end));
%%%%%end of routine %%%
following are the errors i am getting
??? Error using ==> end Incorrect cell or structure reference involving "end". Most likely cause is a reference to multiple elements of a cell or structure followed by additional subscript or structure references.
Error in ==> getCameraInfo at 4 camera_id = camera_info.DeviceInfo.DeviceID(end);
Error in ==> redObjectTrack at 2 [camera_name, camera_id, format] = getCameraInfo(a);
please help me out of this ..Same codes are working for a desktop PC and a webcam..But when i try this on my laptop its not working ..
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Accepted Answer
Image Analyst
on 19 Feb 2012
You can't have a function defined down below your script. I didn't see a function line for the first chunk of your code, which you need. You need something like this as the first line:
function redObjectTrack()
When I do that it runs the getCameraInfo() function fine. All I did was to remove the semicolons so that I could see the outputs, and I renamed format to format1 so as to not overwrite a built-in MATLAB function and it printed out this:
camera_name =
winvideo
camera_info =
AdaptorDllName: 'C:\Program Files\MATLAB\R2011b\toolbox\imaq\imaqadaptors\win64\mwwinvideoimaq.dll'
AdaptorDllVersion: '4.2 (R2011b)'
AdaptorName: 'winvideo'
DeviceIDs: {[1]}
DeviceInfo: [1x1 struct]
camera_id =
1
resolution =
RGB24_960x720
3 Comments
Walter Roberson
on 3 Jul 2017
(As of R2016b it become possible to put a function below a script, but that was not possible in the 2012 time frame.)
Jibin Lukose
on 2 Oct 2017
Me don't have any idea with this MATLAB Track coding, so could you share the edited code, that would run successfully please? @Max & @Image Analyst
More Answers (3)
Jiro Doke
on 19 Feb 2012
Put a breakpoint on line 4 of your function getCameraInfo, and explore your variable camera_info. Maybe your laptop isn't recognizing your webcam.
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Walter Roberson
on 19 Feb 2012
camera_info is a structure array directly or at the DeviceInfo level.
WORAWUT KUNGHUN
on 3 Jul 2017
a = imaqhwinfo;
camera_name = char(a.InstalledAdaptors(end));
camera_info = imaqhwinfo(camera_name);
camera_id = camera_info.DeviceInfo.DeviceID(end);
resolution = char(camera_info.DeviceInfo.SupportedFormats(end));
vid = videoinput(camera_name, camera_id, resolution);
set(vid, 'FramesPerTrigger', Inf);
set(vid, 'ReturnedColorspace', 'rgb')
vid.FrameGrabInterval = 5;
start(vid)
change the resolution in image acquired by webcam command.
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