getsnapshot - Dark image compared to Fly Cap

I've got a problem while using getsnapshot to automatize my image acquisition instead of using PointGrey FlyCap.

All I do is intializing my device and setting all the cam settings I want to have.

This is the Image that is provided by Fly Cap:

And it is of course the image I want to have. When i try to get a picture, with the same device and the same setting via Matlab getsnapshot, this will be the result:

Do I miss any settings?

The values i modify are: Brightness, Exposure, Sharpness, Gain, Gamma, FrameRate(15) and Shutter. But as I said i modify them to be smiliar to Fly Cap. Of course I change the Mode to 'manual' for every of the mentioned settings.

Anybody who could help?

[Anna Jonsson]

I have the same problem, did you find a solution?

Answer 1

[Bhanu Prakash]

Hi Pascal,

As per my understanding, you are facing an issue when you capture an image using the ‘getsnapshot’ function in MATLAB.

This is likely because of a digital artifact with your hardware. The first couple of frames provided by some hardware devices, especially webcams and video cards, may be of low quality and may appear as a dark image .

This artifact can be a result of the image sensor not having warmed up or the device just being started.

You can try the following options while capturing the image:

• When using the ‘getsnapshot’ function, keep the preview window running to avoid starting up the device and to maintain an active image stream.
• You can skip the starting frames (appearing as a dark image) after the device is triggered, using the ‘TriggerFrameDelay’ function in MATLAB as follows:

    % Number of image frames to acquire.
    N = 10;
    % Access the device.
    vid = videoinput('winvideo');
    % Skip the first few frames after the device is %triggered.
    set(vid, 'TriggerFrameDelay', 3);  
    % Configure the number of frames to acquire.
    set(vid, 'FramesPerTrigger', N);
    % Start the acquisition and have it trigger %immediately. Then access the data. 
    triggerconfig(vid, 'Immediate');
    start(vid)
    data = getdata(vid);

For more information on the ‘TriggerFrameDelay’ function, kindly refer to the following documentation:

https://www.mathworks.com/help/imaq/triggerframedelay.html

Hope this helps!