How can i capture image from webcome for recognization

Pls help me this, i have a webcame and i want to capture and save it in a folder for compare with the sample image is saved before.

Many thanks

Answer 1

[Image Analyst]

%=====================================================================
function InitializeVideoCamera(handles)
  % Initialize the video camera.
  global vidobj;  % Video camera object.
  try
    % Initialize Logitech webcam
    vidobj = videoinput('winvideo', 1, 'RGB24_640x480');
    if ~isempty(vidobj)
      src = getselectedsource(vidobj);
      vidobj.FramesPerTrigger = 1;
      axes(handles.axesImage);
      hImage = findobj(handles.axesImage, 'Type', 'image');
      preview(vidobj, hImage);
%       src.ZoomMode = 'manual';
      % Turn on the live video preview.  Display the bounding box over it if there is one selected.
      TurnOnLiveVideo(handles);
    end
    % Turn on the live video preview.  Display the bounding box over it if there is one selected.
    TurnOnLiveVideo(handles);
  catch ME
    errorMessage = sprintf('Error in function logitech_webcam_OpeningFcn.\nNo Logitech webcam detected!\n\nError Message:\n%s', ME.message);
    set(handles.txtInfo, 'string', errorMessage);
    uiwait(warndlg(errorMessage));
  end

%=====================================================================  function snappedImage = SnapImage(handles)
  % Declare imgOriginal.  It might be filled with values here.
  global imgOriginal;  % Declare global so that other functions can see it, if they also declare it global.
  global vidobj;  % Video camera object.
  if isempty(vidobj), return, end;
  try
    snappedImage = getsnapshot(vidobj);
    axes(handles.axesImage);
    hold off;
    axis auto;
    imshow(snappedImage, 'InitialMagnification', 'fit');
    grayImage = rgb2gray(snappedImage);

    % Just for fun, let's get its histogram.
    [pixelCount grayLevels] = imhist(grayImage);
    axes(handles.axesPlot);
    bar(pixelCount); 
    title('Histogram of image');
    xlim([0 grayLevels(end)]); % Scale x axis manually.
    
    imgOriginal = snappedImage;

  catch ME
    errorMessage = sprintf('Error in function btnPreviewVideo_Callback.\nError Message:\n%s', ME.message);
    set(handles.txtInfo, 'string', errorMessage);
    msgboxw(errorMessage);
  end

%=====================================================================
% Turn on the live video preview.  Display the bounding box over it if there is one selected.
function TurnOnLiveVideo(handles)
  global vidobj;  % Video camera object.
  % Bail out if there is no video object class instantiated.
  if isempty(vidobj), return, end;
  % Switch the current graphic axes to handles.axesImage.
  % This is where we want the video to go.
  axes(handles.axesImage);
  % Reset image magnification. Required if you ever displayed an image
  % in the axes that was not the same size as your webcam image.
  hold off;
  axis auto;  
  % Get the handle to the image in the axes.
  hImage = findobj(handles.axesImage, 'Type', 'image');
  % Turn on the live video.
  preview(vidobj, hImage);
  % Put hold on so that displaying our bounding box doesn't blow away the image.
  hold on;
  % Retrieve our x,y coordinates of the bounding box corners.
  GetImageMask(handles);
  % They have been previously set elsewhere as global variables.
  global maskVerticesXCoordinates;
  global maskVerticesYCoordinates;
  if ~(isempty(maskVerticesXCoordinates) || isempty(maskVerticesYCoordinates))
    % If the bounding box coordinates exist,
    % plot the bounding box over the live video.
    plot(maskVerticesXCoordinates, maskVerticesYCoordinates);
  end
  
%   stoppreview(vidobj);
  return; % from TurnOnLiveVideo

[Explorer]

What should i pass as input argument?

Error using InitializeVideoCamera (line 21) Not enough input arguments.

[Walter Roberson]

Call the routine from a GUIDE routine and pass in the handles structure to the routine.

[Explorer]

How to do that ? Can you please tell me step wise?

[Explorer]

This code is for GUIDE ?

Please make code suitable so that I can run it by creating M-file.

[Image Analyst]

Just get rid of the stuff about mask vertices, and replace handles.axesImage with the name of the variable that your axes has.

[Explorer]

I am not making GUI so there is no variable in my case which stores axes. What to do now?

[Image Analyst]

Create an axes with uicontrol(), that is, if the preview function doesn't do it for you if you omit the handle to the axes.

Answer 2

[Image Analyst]

Do you have the Image Acquisition Toolbox and have you run imaqtool yet? You can control the camera and see what it puts in the command window and then paste that into your own m-file.

[Ha Nguyen]

can you show me Brother - I have Aquisition Toolbox but i dont know where to start - I connect my webcame through USB then i use some commands to show it ( video stream) - But how can i get image - Pls show me methods i can do it

many thanks

[Image Analyst]

See code snippets in my other answer.