How do I specify parameter types (specifically Image types) of a function in a .NET assembly created by MATLAB?

Hi everyone!

I have the following code in a MATLAB function;

function [ returnValue] = ProcessImage( passedImage )
originalImage = imread(passedImage);
[rowSize colSize] = size(originalImage);
returnValue = colSize 
end

I built a .NET assembly with this bit of code. I then added it as a reference to a C#.NET application. I now need to pass an image from the .NET application this bit of code, which will process the image and return its column size.

I'm not sure how to go about the type setting. Cuz when I try it out, a syntax error is shown in Visual Studio saying that the argument expected is of type int.

Have I written the MATLAB function declaration correctly?

[Geoff Hayes]

What is passedImage? Is it an image (incorrect) or a (string) filename (with path) to an image?

imread will read an image from a graphics file (see http://www.mathworks.com/help/matlab/ref/imread.html) and so the input must be a filename or URL.

Once the image is read, to get the number of columns just do

 colSize = size(originalImage,2);

In the above, we get the second dimension (number of columns) from the image.

[Lahiru]

Thanks for the reply.

Okay, so now I tried what you suggested. But still a syntax error is shown in Visual Studio saying that the argument expected is of type int.

[Geoff Hayes]

So is the C# application that doesn't' like the return value from ProcessImage? If that is the case, then cast colSize as an integer

 returnValue = int32(colSize);

The above is for a 32-bit signed integer. If something different is needed, then cast as appropriate.

[Lahiru]

This is just a sample code I posted here. In my actual code I take in a string (imagePath - after your suggestion) and return a string. However, in VS2012, both the input params and the return values type is detected as int.