MATLAB: How can i capture image from webcome for recognization

capture image from webcame

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

Best Answer

%=====================================================================

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
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