Index exceeds matrix dimensions

clear all;
C = webcamlist;
if length(C)>2
    fprintf('All three WebCam is Working' );
else
    fprintf('Not All three WebCam is Working' );
end
load('webcamsSceneReconstruction.mat');
vid1 = videoinput('macvideo', 1);
vid2 = videoinput('macvideo', 2);
start([vid1 vid2]);
img1 = getsnapshot(vid1);
img2 = getsnapshot(vid2);
imwrite(img1,'sceneReconstructionLeft.jpg');
imwrite(img2,'sceneReconstructionRight.jpg');
I1 = imread('sceneReconstructionLeft.jpg');
I2 = imread('sceneReconstructionRight.jpg');
I1 = undistortImage(I1,stereoParams.CameraParameters1);
I2 = undistortImage(I2,stereoParams.CameraParameters2);
faceDetector = vision.CascadeObjectDetector;
face1 = step(faceDetector,I1);
face2 = step(faceDetector,I2);
center1 = face1(1:2) + face1(3:4)/2;
center2 = face2(1:2) + face2(3:4)/2;
point3d = triangulate(center1, center2, stereoParams);
distanceInMeters = norm(point3d)/1000;
distanceAsString = sprintf('%0.2f', distanceInMeters);
I1 = insertObjectAnnotation(I1,'rectangle',face1,distanceAsString,'FontSize',18);
I2 = insertObjectAnnotation(I2,'rectangle',face2, distanceAsString,'FontSize',18);
I1 = insertShape(I1,'FilledRectangle',face1);
I2 = insertShape(I2,'FilledRectangle',face2);
%imshowpair(I1, I2, 'montage');

Why [am] i getting this error in both center1 and center2 and any way to prevent this error i have to represent this to my external

Answer 1

[Azzi Abdelmalek]

Check the sizes of the variables face1 and face2

[Ankit Singh]

both 0x4 double

[dpb]

What I expected. So, the object detector logic returned nothing recognizable. Your mission, should you choose to accept, is to investigate "why"....we've no way to know from the info posted.

[Image Analyst]

No face detected so I guess there is either no one in the picture, or, my guess, he's wearing his ninja outfit.

[Ankit Singh]

Any way to prevent this again and Again getting this mostly face recognition code like this

center1 = face1(1:2) + face1(3:4)/2;
center2 = face2(1:2) + face2(3:4)/2;

[Ankit Singh]

if the person wearing specs then this object detector will work and the person is sitting in front of webcam i mean face is towards camera, not tilted then why it is showing error

[Ankit Singh]

Index exceeds matrix dimensions.

Error in Depth (line 22) center1 = face1(1:2) + face1(3:4)/2;

Error in EyeClassifier (line 4) Depth;

>> who face1

Your variables are:

face1

whos face1 Name Size Bytes Class Attributes

face1      0x4                 0  double

I think, I'm accessing face(1:2) 1st row and 2nd column but face1 doesn't have 1st row after checking the size because

faceDetector = vision.CascadeObjectDetector;
face1 = step(faceDetector,I1);
face2 = step(faceDetector,I2);

step(faceDetector,I1) not detected face

Any solution this error, how to prevent this error

[ahmed nasr]

hello i have the same error for months nw .. what did you come up with ??

[Jan]

@ahmed nars: The question is almost 2 years old. Prefer to open you own thread and post the details. What is "months nw"?

[Torsten]

n(o)w

[ahmed nasr]

@Jan Simon: A few months from our present time. Ahmed Nasr* @Torsten: nOOOOOOw

[Torsten]

Yes, I know. Why do you shout ?

[Jan]

@ahmed nasr: I thought "months nw" is the failing variable... You are working on some code for months now and it has still errors? As said already: Please open a new thread and post the relevant part of the code and some example inputs (e.g. created by rand).

[Walter Roberson]

Cascade object detection relies on patterns that are not certain to be present even if there is s face in the input images, and there is no certainty that the input has a face at all. The code is wrong for not testing to be sure that a face was detected. The code is also wrong for the case where more than one face is detected.