how to insert a rectangle to a video preview

im using my webcam to take an image of the user. I want to insert a rectangle to the video preview so that user can put his face within that boundary.

cem=webcam('Lenovo EasyCam');
preview(cem);
img=snapshot(cem);
preview(img);
hold on

thisBB = [10 10 300 300];

rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],'EdgeColor','r','LineWidth',2 );

[hervey he]

Hi man, have you resoluted this problem? I also want that fuction too.

Answer 1

[Image Analyst]

I don't think you want these lines:

img=snapshot(cem);
preview(img);
hold on

Getting a snapshot into a variable img is fine (not sure if it would freeze the video after that though) but then passing an image to preview instead of a video object will probably cause problems. Play around with hold on to see if you need to put it before or after rectangle or if you even need it at all.

[Thushar Praveen]

I want rectangle in the live video preview itself

cem=webcam('Lenovo EasyCam'); preview(cem); pause(); img=snapshot(cem); hold on thisBB = [10 10 300 300]; rectangle('Position',[thisBB(1),thisBB(2),thisBB(3),thisBB(4)],'EdgeColor','r','LineWidth',2 );

Answer 2

[Thushar Praveen]

I want rectangle in the live video preview itself

 cem=webcam('Lenovo EasyCam');
 preview(cem);
 pause();
 img=snapshot(cem);
 hold on 
 thisBB = [10 10 300 300];
 rectangle('Position',[thisBB(1),thisBB(2),thisBB(3),thisBB(4)],'EdgeColor','r','LineWidth',2 );

[Tung Le Thanh]

I am impossible