I am getting this error while running a matlab code for face detection and tracking Error in noseDetector = vision.Cas​cadeObject​Detector('​Nose', 'UseROI', true);

% Create a cascade detector object. faceDetector = vision.CascadeObjectDetector();

% Read a video frame and run the detector. videoFileReader = vision.VideoFileReader('visionface.avi'); videoFrame = step(videoFileReader); bbox = step(faceDetector, videoFrame);

% Draw the returned bounding box around the detected face. videoOut = insertObjectAnnotation(videoFrame,'rectangle',bbox,'Face'); figure, imshow(videoOut), title('Detected face');

% Get the skin tone information by extracting the Hue from the video frame % converted to the HSV color space. [hueChannel,~,~] = rgb2hsv(videoFrame);

% Display the Hue Channel data and draw the bounding box around the face. figure, imshow(hueChannel), title('Hue channel data'); rectangle('Position',bbox(1,:),'LineWidth',2,'EdgeColor',[1 1 0]) % Detect the nose within the face region. The nose provides a more accurate % measure of the skin tone because it does not contain any background % pixels. noseDetector = vision.CascadeObjectDetector('Nose', 'UseROI', true); noseBBox = step(noseDetector, videoFrame, bbox(1,:));

% Create a tracker object. tracker = vision.HistogramBasedTracker;

% Initialize the tracker histogram using the Hue channel pixels from the % nose. initializeObject(tracker, hueChannel, noseBBox(1,:));

% Create a video player object for displaying video frames. videoInfo = info(videoFileReader); videoPlayer = vision.VideoPlayer('Position',[300 300 videoInfo.VideoSize+30]);

% Track the face over successive video frames until the video is finished. while ~isDone(videoFileReader)

    % Extract the next video frame
    videoFrame = step(videoFileReader);

    % RGB -> HSV
    [hueChannel,~,~] = rgb2hsv(videoFrame);

    % Track using the Hue channel data
    bbox = step(tracker, hueChannel);

    % Insert a bounding box around the object being tracked
    videoOut = insertObjectAnnotation(videoFrame,'rectangle',bbox,'Face');    

    % Display the annotated video frame using the video player object
    step(videoPlayer, videoOut);

end % Release resources release(videoFileReader); release(videoPlayer);

Answer 1

[Dima Lisin]

What is the error message you are seeing? Could it be that there is no face in that video frame?

Answer 2

[Prasad Kalane]

Correct following line of code:

% noseDetector = vision.CascadeObjectDetector('Nose', 'UseROI', true);
    noseDetector = vision.CascadeObjectDetector('Nose');
    % noseBBox = step(noseDetector, videoFrame, bbox(1,:));
    noseBBox = step(noseDetector, videoFrame);

Use your own Nose training set to train classifier,as it is composed of weak classifiers(As documented)

[Dima Lisin]

Hi Prasad,

This would not fix the problem. Neelum is trying to detect the nose inside the bounding box containing the face, not in the entire image.