MATLAB: How Do I set Camera Exposure in MATLAB

exposureexposure timeImage Acquisition Toolboxset

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

Best Answer

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

Related Solutions

MATLAB: Recently I use image acquistion toolbox, the image captured is very gloothe

You're trying to display an image in the YCbCr color space (that's what the I420 in your videoinput line means) with a function that is expecting RGB data.

If you do:

 vid = videoinput('winvideo', 1, 'I420_640x480');
 vid.ReturnedColorSpace = 'RGB';

then the toolbox will convert the data to RGB data when you call getsnapshot or getdata. If you actually want the YCbCr data you can omit changing the ReturnedColorSpace property and instead convert the data before displaying it:

 frame = getsnapshot(vid);
 imshow(ycbcr2rgb(frame));

MATLAB: Do I receive the error “GETDATA timed out before FRAMES were available” when using GETDATA in Image Acquisition Toolbox 4.3 (R2012a)

The error message on your Linux machine is caused by the delay between the device and MATLAB, which is not a constant value and this related to your system and device driver. This is the reason why it happens at random iterations. Due to the delay, there are no available frames when the time exceeds the Timeout value. To ensure that you are getting data from the camera, you have two options:

1. Setting a larger Timeout value for the object

set(vid,'Timeout',50); %set the Timeout property of VIDEOINPUT object 'vid' to 50 seconds

2. Before GETDATA, wait until there's an available frame

while get(vid,'FramesAvailable')<1  %Wait until at least 1 frame is available
      unavailable=1;
end

Best Answer

Related Solutions

MATLAB: Recently I use image acquistion toolbox, the image captured is very gloothe

MATLAB: Do I receive the error “GETDATA timed out before FRAMES were available” when using GETDATA in Image Acquisition Toolbox 4.3 (R2012a)

Related Question