Help with Gui for real time webcam video input

I had a code for face detection using vision.CascadeObjectDetector in real time and i want to input the code into a gui with 1 start buttona and 1 axes. I had try by editing this code

if true

obj = imaq.VideoDevice('winvideo',1,'YUY2_320x240');

set(obj,'ReturnedColorSpace','rgb');

figure('menubar','none','tag','webcam');

% tell matlab to start the webcam on user request, not automatically

triggerconfig(obj, 'manual');

% we need this to know the image height and width

vidRes = get(obj, 'VideoResolution');

% image width

imWidth = vidRes(1);

% image height

imHeight = vidRes(2);

% number of bands of our image (should be 3 because it's RGB)

nBands = get(obj, 'NumberOfBands');

% create an empty image container and show it on axPreview

hImage = image(zeros(imHeight, imWidth, nBands), 'parent', handles.axPreview);

% begin the webcam preview

preview(obj, hImage);

end

into this

if true

obj = imaq.VideoDevice('winvideo',1,'YUY2_320x240');

set(obj,'ReturnedColorSpace','rgb');

figure('menubar','none','tag','webcam');

% tell matlab to start the webcam on user request, not automatically

triggerconfig(obj, 'manual');

while(true)

frame=step(obj);

%Detect faces.

bboxes = step(faceDetector,frame);

%Annotate detected faces.

IFaces = insertObjectAnnotation(frame,'rectangle',bboxes,'face');

hImage = image(IFaces,'border','tight', handles.axPreview);

% begin the webcam preview

preview(obj, hImage);

end

but failed. Could anyone teach me how to input both the webcam and the bounding box of the face in real time into the same axes? Thanks.