MATLAB: Am I unable to use the function IMTRANSFORM in an application created with MATLAB Compiler 7.10 (R2009a)

builderImage Processing ToolboxjarjavaMATLAB Compilerstand-alonestandalone

My program loads the transformation structure (TFORM) that is passed to IMTRANSFORM from a MAT file. The program runs fine within MATLAB but fails in compiled mode with the following error:

 Warning: Could not find appropriate function on path loading function handle
 C:\MATLAB\R2009a\toolbox\images\images\private\inv_piecewiselinear.mexw32>inv_piecewiselinear

Compiling the application using the MATLAB Builder JA shows the following additional information:

 Exception caught: com.mathworks.toolbox.javabuilder.MWException: Error using ==> feval
 Undefined function handle.

Best Answer

The TFORM structure contains a function handle to a function from the Image Processing Toolbox. Since the structure gets loaded at runtime, the static analysis that is done by the MATLAB Compiler fails to identify the file as a dependency.

To work around this issue, add the following "function pragma" line of code to the beginning of your MATLAB program to indicate that the function CP2TFORM should be included in the compilation:

%#function cp2tform

The function CP2TFORM will automatically include the rest of the files that are needed for the TFORM structure to be loaded/restored correctly from the MAT file.

Related Solutions

MATLAB: Does the stand-alone application fail to find MEX-files from ‘private’ folders in the MATLAB toolboxes when deployed

The current fix to this problem is to recreate the MATLAB path on the deployment computer.

For example, consider the DLL:

C:\matlab6p5\toolbox\images\images\private\imhistc.dll.

On the deployment computer, you will need to create the entire tree:

c:\matlab6p5\toolbox\images\images\private\imhistc.dll.

MATLAB: Does the internal structure of the “tform” structure array returned by CP2TFORM change during execution for Image Processing Toolbox 5.0.1 (R14SP1)

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

This issue is a known error in the documentation for Image Processing Toolbox 5.0.1 (R14SP1). CP2TFORM was enhanced for this version in order to handle ill-conditioned matrices. As a consequence, the internal structure of the "tform" structure array returned by CP2TFORM can change during execution for such cases.

You should refrain from accessing the internal structures of the "tform" array returned by the CP2TFORM function. Alternatives include using "method functions" such as TFORMFWD, TFORMINV, IMTRANSFORM, and TFORMARRAY to suit your needs.

As an example, for the script mentioned above, replace the following:

ss = tform.tdata.Tinv(2,1); 
sc = tform.tdata.Tinv(1,1);
angle = atan2(ss,sc)*180/pi
scale = sqrt(ss*ss + sc*sc)

with

u = [0 1];
v = [0 0];
[x, y] = tformfwd(tform, u, v);
dx = x(2) - x(1);
dy = y(2) - y(1);
angle = (180/pi) * atan2(dy, dx)
scale = 1 / sqrt(dx^2 + dy^2)

Best Answer

Related Solutions

MATLAB: Does the stand-alone application fail to find MEX-files from ‘private’ folders in the MATLAB toolboxes when deployed

MATLAB: Does the internal structure of the “tform” structure array returned by CP2TFORM change during execution for Image Processing Toolbox 5.0.1 (R14SP1)

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