classifyVideo function does not work on Mac

I am trying this example of Transfer Learning "Deep Learning: Transfer Learning in 10 lines of MATLAB Code".

All the given code works. But when I try to classify objects in live video using Macbook cam (as shown in the end of this video), the classifyVideo(myNet) function gives an error "Unrecognized function or variable 'classifyVideo'."

Can somebody tell me how I can classify objects using live cam on Macbook?

Answer 1

[Prabhan Purwar]

Hi,

You can recreate the functionality by writing your own function which takes as input the network obj and performs the following tasks:

1. Initializes webcam
2. Runs infinite while loop that exits when q is pressed
3. Within while loop:
4. Checks for 'q' keypress
5. Captures and image and resizes the image
6. Classifies the image
7. Updates figure to display current image and classification label

A sample function "classifyVideo.m" is pasted below for your reference:

function [] = classifyVideo(net)

% Initialize webcam

cam = webcam;

% Initialize figure

hf = figure;

while 1

% compares the current character to q

% if 'q' is pressed exit

if strcmp(get(hf,'currentcharacter'),'q')

close(hf)

break

end

% Acquire a single image

rgbImage = snapshot(cam);

% Resize image to fit AlexNet dimensions

resizedImage = imresize(rgbImage, [227 227]);

% Classify Image

label = classify(net,resizedImage);

% Display the image.

imshow(rgbImage);

% Display label

title(label);

% Update figure

hold on;

drawnow

% force the event queue to flush

figure(hf)

drawnow

end

% Clear camera object

clear('cam');

end

You can quickly test the function using the following:

>> net = alexnet;

>> classifyVideo(net) ;

You will have to install the "MATLAB Support Package for USB Webcams" from Add-On Explorer to be able to use the "webcam" command in the function.

More information about webcam use with MATLAB can be found here:

https://www.mathworks.com/help/supportpkg/usbwebcams/ug/acquire-images-from-webcams.html