Undefined function or variable

that is the whole code which should get face detection with distance

 load('callast.mat');

 double faceDetector();
 vid = videoinput('macvideo', 1, 'YCbCr422_1280x960');%left
 vid2 = videoinput('macvideo', 3, 'YCbCr422_1280x960');%right

 triggerconfig([vid vid2],'manual');
 vid2.FramesPerTrigger = 10;
 vid.FramesPerTrigger = 10;

start([vid vid2]);
pause(1)

 trigger([vid vid2]);

 I1 = getsnapshot(vid);
 I2 = getsnapshot(vid2);

 % I1 = undistortImage(T1,stereoParams.CameraParameters1);
%I2 = undistortImage(T2,stereoParams.CameraParameters2);

 faceDetector = vision.CascadeObjectDetector;

 face1 = faceDetector(I1);
 face2 = 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 meters', 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');

the error

 Undefined function or variable 'stereoParams'.

 point3d = triangulate(center1, center2, stereoParams);

Answer 1

[Walter Roberson]

You did not call estimateCameraParameters to generate the stereo parameters.

[ahmed nasr]

i added a loop i forgot

 load('callast.mat');

 double faceDetector();
 vid = videoinput('macvideo', 1, 'YCbCr422_1280x960');%left
 vid2 = videoinput('macvideo', 3, 'YCbCr422_1280x960');%right

 triggerconfig([vid vid2],'manual');
 vid2.FramesPerTrigger = 10;
 vid.FramesPerTrigger = 10;

start([vid vid2]);
pause(1)

 trigger([vid vid2]);

 for x = 1:100
 I1 = getsnapshot(vid);
 I2 = getsnapshot(vid2);

 % I1 = undistortImage(T1,stereoParams.CameraParameters1);
%I2 = undistortImage(T2,stereoParams.CameraParameters2);

 faceDetector = vision.CascadeObjectDetector;

 face1 = faceDetector(I1);
 face2 = 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 meters', 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);
 end 

 imshowpair(I1, I2, 'montage');

the error changed

 Index exceeds matrix dimensions.
 center1 = face1(1:2) + face1(3:4)/2;

[ahmed nasr]

i loaded the calibration file isn't that the camera parameters ??

[Walter Roberson]

We have no idea what is stored in your callast.mat file.

Even if there is a variable named stereoParams in there, if this code is inside a function, the Just In Time compiler would not believe it exists. You should not "poof" variables into exists by using load() without an output: you should assign the results of load() to a variable and either access the resulting struct directly or pull out parts of it, like

filedata = load('callast.mat');
stereoParams = filedata.stereoParams;

Note by the way that your line

   double faceDetector();

means exactly the same thing as

double('faceDetector()');

which computes [102 97 99 101 68 101 116 101 99 116 111 114 40 41] and then throws it away. MATLAB does not have type declarations.

Index exceeds matrix dimensions.
center1 = face1(1:2) + face1(3:4)/2;

Your code assumes that the face detector found exactly one face. You should not assume that. You should be testing the size of the output to determine whether it found anything, and you should assume it might have found multiple faces (in which case the information for any one face is a row in the results, whereas you assume you can use linear indexing, which will fail if multiple faces were returned.

[ahmed nasr]

thank you you have been so helpful... but still i can't understand

[Walter Roberson]

Delete the line

    double faceDetector();

Change

load('callast.mat')

to

filedata = load('callast.mat');
stereoParams = filedata.stereoParams;

Change

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

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

 followed by the rest of your code

to

 if ~isempty(face1) & ~isempty(face2)

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

   followed by the rest of your code and then

 end

so that the rest of your code is not executed if no face was detected.

[ahmed nasr]

i did what u told me but the filedata part gave me an error but everything else ran smoothly with no errors but no output .

load('callast.mat');
vid = videoinput('macvideo', 1, 'YCbCr422_1280x960');%left
vid2 = videoinput('macvideo', 2, 'YCbCr422_1280x960');%right
triggerconfig([vid vid2],'manual');
vid2.FramesPerTrigger = 10;
vid.FramesPerTrigger = 10;
start([vid vid2]);
pause(1)
trigger([vid vid2]);
I1 = getsnapshot(vid);
I2 = getsnapshot(vid2);
faceDetector = vision.CascadeObjectDetector;
face1 = faceDetector(I1);
face2 = faceDetector(I2);
if ~isempty(face1) & ~isempty(face2)
   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 meters', 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');
end

[ahmed nasr]

but thats a nice breakthrough, thank you Walter. i don't know how i forgot this loop

[Walter Roberson]

I do not see any loop in your code.

[ahmed nasr]

The condition am sorry, ishould add a loop to take screenshots and analyze, right ?

[Walter Roberson]

You have two choices:

First possibility:

 maxframe = 10;

 vid = videoinput('macvideo', 1, 'YCbCr422_1280x960');%left
 vid2 = videoinput('macvideo', 3, 'YCbCr422_1280x960');%right
 faceDetector = vision.CascadeObjectDetector;

 for frame = 1 : maxframe
   I1 = getsnapshot(vid);
   I2 = getsnapshot(vid2);
   face1 = faceDetector(I1);
   face2 = faceDetector(I2);
   if ~isempty(face1) & ~isempty(face2)
     center1 = face1(1, 1:2) + face1(1, 3:4)/2;
     center2 = face2(1, 1:2) + face2(1, 3:4)/2;
     point3d = triangulate(center1, center2, stereoParams);
     distanceInMeters = norm(point3d)/1000;
     distanceAsString = sprintf('%0.2f meters', 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');
     drawnow();
   end
 end

Second possibility:

 maxframe = 10;

 vid = videoinput('macvideo', 1, 'YCbCr422_1280x960');%left
 vid2 = videoinput('macvideo', 3, 'YCbCr422_1280x960');%right
 faceDetector = vision.CascadeObjectDetector;
 vid2.FramesPerTrigger = maxframe;
 vid.FramesPerTrigger = maxframe;
 start([vid vid2]);
 pause(1)
 trigger([vid vid2]);

 frames1 = getdata(vid);
 frames2 = getdata(vid);

 for frame = 1 : size(frames1, 4)
   I1 = frames1(:,:,:,frame);
   I2 = frames1(:,:,:,frame);
   face1 = faceDetector(I1);
   face2 = faceDetector(I2);
   if ~isempty(face1) & ~isempty(face2)
     center1 = face1(1, 1:2) + face1(1, 3:4)/2;
     center2 = face2(1, 1:2) + face2(1, 3:4)/2;
     point3d = triangulate(center1, center2, stereoParams);
     distanceInMeters = norm(point3d)/1000;
     distanceAsString = sprintf('%0.2f meters', 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');
     drawnow();
   end
 end