Error using imaq.VideoDevice

Hello, I made such a code for my project, but

Error using imaq.internal.VideoDeviceInternalNo device is available at the specified DEVICEID. See IMAQHWINFO('winvideo').Error in imaq.VideoDevice

My camera: a4 tech pk-636k

I'm getting an error like this, if you can help I'd appreciate it.

    %% Detecting Motions Using Gaussian Mixture MOdel
    %
    %
    %
    %https://ch.mathworks.com/help/vision/examples/detecting-cars-using-gaussian-mixture-models.html
    %
    %%
    clear all; close all;
    clc;
    %%
    FRAME_WIDTH = 1280;
    FRAME_HEIGHT = 720;
    vidDevice = imaq.VideoDevice('winvideo', 2, strcat('MJPG_',num2str(FRAME_WIDTH),'x',num2str(FRAME_HEIGHT)), ... % Acquire input video stream
        'ROI', [1 1 FRAME_WIDTH FRAME_HEIGHT], ...
        'ReturnedColorSpace', 'rgb');
    foregroundDetector = vision.ForegroundDetector('NumGaussians', 3, ...
        'NumTrainingFrames', 50);
    blobAnalysis = vision.BlobAnalysis('BoundingBoxOutputPort', true, ...
        'AreaOutputPort', false, 'CentroidOutputPort', false, ...
        'MinimumBlobArea', 3500);
    se = strel('square', 5); % morphological filter for noise removal
    %% Train Foreground Detector
    disp('Training');
    for i = 1:150
        disp(strcat('step#',num2str(i)));
        frame = step(vidDevice); % read the next video frame
        foreground = step(foregroundDetector, frame);
    end
    disp('Training Complete');
    %%
    for i=1:400
        rgbFrame = step(vidDevice);
        rgbFrame=flip(rgbFrame,2);
        grayFrame = rgb2gray(rgbFrame);
        grayFrame = imgaussfilt(grayFrame,4); 
        % Detect the foreground in the current video frame
        foreground = step(foregroundDetector, rgbFrame);
        % Use morphological opening to remove noise in the foreground
        filteredForeground = imopen(foreground, se);
        % Detect the connected components with the specified minimum area, and
        % compute their bounding boxes
        bbox = step(blobAnalysis, filteredForeground);
        % Draw bounding boxes around the detected cars
        result = insertShape(rgbFrame, 'Rectangle', bbox, 'Color', 'green','LineWidth', 5);
        % Display the number of cars found in the video frame
        numCars = size(bbox, 1);
        result = insertText(result, [10 10], numCars, 'BoxOpacity', 1, ...
            'FontSize', 14);
        figure(5),imshow(result);
        %    step(videoPlayer, result);  % display the results    
    end
    %%
    release(vidDevice)

Answer 1

[Image Analyst]

What does this show fpr you?

>> imaqhwinfo

ans =

struct with fields:

InstalledAdaptors: {'gentl' 'lumeneraimaq' 'winvideo'}

MATLABVersion: '9.11 (R2021b)'

ToolboxName: 'Image Acquisition Toolbox'

ToolboxVersion: '6.5 (R2021b)'

[trk]

Sir, I'm sorry, I don't know much about matlab, I didn't know exactly where to cut this code.

[Image Analyst]

Type that into the command window.

[trk]

Sir is giving eror again.

[Image Analyst]

You're not supposed to paste in the answer for my system. You're supposed to just call imaqhwinfo

imaqhwinfo

Type that into the command line.

[trk]

[Walter Roberson]

    vidDevice = imaq.VideoDevice('winvideo', 2, strcat('MJPG_',num2str(FRAME_WIDTH),'x',num2str(FRAME_HEIGHT)), ... % Acquire input video stream
        'ROI', [1 1 FRAME_WIDTH FRAME_HEIGHT], ...
        'ReturnedColorSpace', 'rgb');

You are asking for the second device (#2) but you only have one winvideo device. Try

 videoRes = sprintf('MJPG_%dx%d', FRAME_WIDTH, FRAME_HEIGHT)
 % Acquire input video stream.  Instantiate vidDevice object.
 vidDevice = imaq.VideoDevice('winvideo', 1, ...
     videoRes, ... 
     'ROI', [1, 1, FRAME_WIDTH, FRAME_HEIGHT], ...
     'ReturnedColorSpace', 'rgb');

[Image Analyst]

See if the attached program runs for you. It is more robust than what you've done and tried to automatically find the video source. Works for winvideo and my Logitech web cam.

[trk]

Sir, it is giving an error again. I have one more question for you. There would be an article for Motion Detection that I can read, a resource I can use, for example, if you could give me advice on how it works, I would be very happy because this is my final project, but there is always a problem, I need to research thoroughly and for my presentation.

[Image Analyst]

I don't see a line number there. Tell the debugger to run but stop on any error and tell me what line number it is throwing the error on.

Answer 2

[yanqi liu]

yes，sir，may be use

vidDevice = imaq.VideoDevice('winvideo', 1, strcat('MJPG_',num2str(FRAME_WIDTH),'x',num2str(FRAME_HEIGHT)), ... % Acquire input video stream
        'ROI', [1 1 FRAME_WIDTH FRAME_HEIGHT], ...
        'ReturnedColorSpace', 'rgb');

Answer 3

[Pham]

Hello, I made such a code for my project, but

Error using imaq.internal.VideoDeviceInternal

Invalid VIDEOFORMAT 'YUY2_640x480' specified. VIDEOFORMAT must be specified as a string. The available

formats on this device are {RGB24_640x480}.

Error in imaq.VideoDevice

[Walter Roberson]

@Pham

What is your call to imaq.VideoDevice ?

What hardware (brand and model) of camera are you using?