How Do I set Camera Exposure in MATLAB?

Hi, I was trying to adjust the exposure for my webcamera, I looked on my image Acquisition toolbox and when i adjust the exposer on there it seems to use the command 'src.Exposure = 10;' (for when you want the exposure to be 10)

I wanted to set my camera exposure to say 20, and i used the same idea but it doesnt seem to work? I tried it for other numbers eg, 60, 100 etc but it seems there is no affect.

Bellow shows the code i am using to test it.

imaqhwinfo ('winvideo', 1);
video = videoinput('winvideo',1,'RGB24_640x480');

src.Exposure = 20; % changes exposure 

preview(video); %Launches video preview window

Answer 1

[Walter Roberson]

What is src in your code? Do you mean video.Exposure ?

[jim]

Hi, thanks for the reply i used this in the end.

vid = videoinput('winvideo', 1, 'RGB24_640x480');
src = getselectedsource(vid);
vid.FramesPerTrigger = 1;
preview(vid);
src.Exposure = 20;

[KAE]

If you are having trouble I recommend troubleshooting with imaqtool which will list the command line commands as you change something like the exposure time.

This let me discover that I needed to add a ExposureTimeControl command before I changed the exposure time,

vid = videoinput('winvideo', 1, 'RGB24_640x480'); % Actually a different camera
src = getselectedsource(vid);
src.ExposureTimeControl = 'normal'; % Needed to alter the exposure time
src.ExposureTime = 2.0;

Also the units of ExposureTime are seconds...just mentioning this because it is not specified on the imaqtool GUI.