Controlling uEye µEye camera in Matlab with shared library by loadlibrary

Hi everbody!

I'm trying to control a uEye camera with Matlab. I don't want to do anything fancy but this is the first time I'm doing such a thing so I'm kind of stuck right now.

So far I have tried to use the loadlibrary(...) functionality with the installed dll-file but always ended up in a mess of errors and warnings. I think my main problem is the use of pointers in Matlab which is necessary for some of the library's functions.

Does anybody have experience with that kind of programming? Or can anybody provide me with a sample code?

Thank you for your help!

[Adam Wyatt]

Have a look at my blog for information on how to do this:

1. .NET interface
2. mex interface

Answer 1

[Adam Wyatt]

The issue is not quite to do with handling pointers - Matlab does that quite well when connecting to DLLs - you have to pass a dummy variable in place of the pointer and then matlab appends the result to the return parameters:

e.g.

int GrabImage(uint8 *data);

becomes

[ret, data] = GrabImage(zeros(SizeVectorOfImage));

where the original function returns a success/failure error code. I believe the dummy variable needs to have allocated sufficient memory to hold the data, but I cannot remember exactly - its been a long time since I used this approach.

The actual problem comes from linking with the other libraries and using non-native data types. In general, I found one has to write a wrapper dll, or a mex file to interface between Matlab and the uEye DLL. You can then use this to allocated memory and help speed things up. However, this gets cumbersome as you have to implement each function manually.

Alternatively you can access the .NET assembly directly, although you have to work around the fact that Matlab does not use pointers. Here is an example:

Remember to "EXIT" your camera before trying to re-initialise the same camera

%   Add NET assembly if it does not exist
%   May need to change specific location of library
asm = System.AppDomain.CurrentDomain.GetAssemblies;
if ~any(arrayfun(@(n) strncmpi(char(asm.Get(n-1).FullName), ...
        'uEyeDotNet', length('uEyeDotNet')), 1:asm.Length))
    NET.addAssembly(...
        'C:\Program Files\IDS\uEye\Develop\DotNet\signed\uEyeDotNet.dll');
end

%   Create camera object handle
cam = uEye.Camera;

%   Open 1st available camera
%   Returns if unsuccessful
if ~strcmp(char(cam.Init), 'SUCCESS')
    error('Could not initialize camera');
end

%   Set display mode to bitmap (DiB)
if ~strcmp(char(cam.Display.Mode.Set(uEye.Defines.DisplayMode.DiB)), ...
        'SUCCESS')
    error('Could not set display mode');
end

%   Set colormode to 8-bit RAW
if ~strcmp(char(cam.PixelFormat.Set(uEye.Defines.ColorMode.SensorRaw8)), ...
        'SUCCESS')
    error('Could not set pixel format');
end

%   Set trigger mode to software (single image acquisition)
if ~strcmp(char(cam.Trigger.Set(uEye.Defines.TriggerMode.Software)), 'SUCCESS')
    error('Could not set trigger format');
end

%   Allocate image memory
[ErrChk, img.ID] = cam.Memory.Allocate(true);
if ~strcmp(char(ErrChk), 'SUCCESS')
    error('Could not allocate memory');
end

%   Obtain image information
[ErrChk, img.Width, img.Height, img.Bits, img.Pitch] ...
    = cam.Memory.Inquire(img.ID);
if ~strcmp(char(ErrChk), 'SUCCESS')
    error('Could not get image information');
end

%   Acquire image
if ~strcmp(char(cam.Acquisition.Freeze(true)), 'SUCCESS')
    error('Could not acquire image');
end

%   Extract image
[ErrChk, tmp] = cam.Memory.CopyToArray(img.ID); 
if ~strcmp(char(ErrChk), 'SUCCESS')
    error('Could not obtain image data');
end

%   Reshape image
img.Data = reshape(uint8(tmp), [img.Width, img.Height, img.Bits/8]);

%   Draw image
himg = imshow(img.Data, 'Border', 'tight');

%   Acquire & draw 100 times
for n=1:100
    %   Acquire image
    if ~strcmp(char(cam.Acquisition.Freeze(true)), 'SUCCESS')
        error('Could not acquire image');
    end

      %   Extract image
      [ErrChk, tmp] = cam.Memory.CopyToArray(img.ID); 
      if ~strcmp(char(ErrChk), 'SUCCESS')
          error('Could not obtain image data');
      end

      %   Reshape image
      img.Data = reshape(uint8(tmp), [img.Width, img.Height, img.Bits/8]);

      %   Draw image
      set(himg, 'CData', img.Data);
      drawnow;
  end

%   Close camera
if ~strcmp(char(cam.Exit), 'SUCCESS')
    error('Could not close camera');
end

[Yao Qiu]

Hello, I am using the .NET framework with MATLAB to program the IDS ueye camera, but now I have problems with following issues:

I want to do the subsampling both in horizontal and vertical orientation, but from the uEye .NET manual, there is no options for subsampling in both orientation:

uEye.Defines.SubsamplingMode.Vertical2X

uEye.Defines.SubsamplingMode.Horizontal2X

uEye.Defines.SubsamplingMode.Vertical3X

uEye.Defines.SubsamplingMode.Horizontal3X

uEye.Defines.SubsamplingMode.Vertical4X

uEye.Defines.SubsamplingMode.Horizontal4X

uEye.Defines.SubsamplingMode.Vertical5X

uEye.Defines.SubsamplingMode.Horizontal5X

uEye.Defines.SubsamplingMode.Vertical6X

uEye.Defines.SubsamplingMode.Horizontal6X

IuEye.Defines.SubsamplingMode.Vertical8X

uEye.Defines.SubsamplingMode.Horizontal8X

uEye.Defines.SubsamplingMode.Vertical16X

uEye.Defines.SubsamplingMode.Horizontal16X

uEye.Defines.SubsamplingMode.Disable

It says that the two parameters Vertical and Horizontal can be linked by logical OR, I tried to do that but failed and here is the error:

cam.Size.Subsampling.Set(uEye.Defines.SubsamplingMode.Vertical4X|uEye.Defines.SubsamplingMode.Horizontal4X);

Error : Undefined operator '|' for input arguments of type 'uEye.Defines.SubsamplingMode'.

So do you know how to solve this problem? I am looking foward to you answer and I would be very appreciated about that

[Will Reeves]

Thanks for the code... I just get an error on the first command "cam.Init" with the "IS_DEVICE_IN_USE" return value (it isn't in use... I unplug and replug just before running the code. Is something else possibly grabbing the camera?)

[Jun]

hi Adam,

the code works with 'SensorRaw8' being 'Mono8' instead. Do you have any idea how to make it work in rgb mode? I tried 'SensorRaw8', the image seems to be close to correct but with some weird grid of darker pixels.

%%%%%%%%%%%%%%

Just found out the solution for my ids camera,

when set in Mono8 mode (grayscale), the reshape works in the following code:

img.Data = reshape(uint8(tmp), [img.Width, img.Height, img.Bits/8]);

To be able to get RGB image, switch Mono8 to RGB8Packed:

cam.PixelFormat.Set(uEye.Defines.ColorMode.RGB8Packed)

and the reshape has to be the following process:

tempData = reshape(uint8(tmp), [img.Bits/8,img.Width,img.Height]);

img.Data = permute(tempData, [2 3 1]);

if not this way the data is reshaped in wrong order. You might need to play with the reshape and permute parameters to make your ids camera work correctly.