MATLAB: Unrecognized function or variable ‘transformPointsInverse’

Question

If I try to invoke or call 'help' on transformPointsInverse or transformPointsForward, I get the titular message: the function is not found. I have checked for typos.

I'm on 2019b and I have the Image Processing Toolbox; I can imwarp and imtransform to my heart's content. And I can see these functions in the docs, ready to help me transform points into new spaces. But the command line? Never heard of them, mate.

Does anyone have the foggiest why MATLAB might not be able to find this?

Answer 1

Hi Christopher,

The help of 'transformPointsInverse' and 'transformPointsForward' doesn't work, because these are methods of few objects present in Image Processing Toolbox, but not the functions themselves.

These methods are present in the following objects within the toolbox and will be used while accessing those objects. The objects are:

• geometricTransform3d (https://www.mathworks.com/help/images/ref/geometrictransform3d.html)
• geometricTransform2d (https://www.mathworks.com/help/images/ref/geometrictransform2d.html)
• affine2d (https://www.mathworks.com/help/images/ref/affine2d.html)
• affine3d (https://www.mathworks.com/help/images/ref/affine3d.html)
• projective2d (https://www.mathworks.com/help/images/ref/projective2d.html)

To access the help of the respective methods from MATLAB help. Perform help on any of the above objects in command prompt and click on the links for the respective functions in the help.

% For example, try the following in MATLAB help for affine3d
>> help affine3d
% Then click on the respective links of the methods placed in the command window
% Another way to directly access is
>> help affine3d/transformPointsForward
>> help affine3d/transformPointsInverse

Hope this helps.

Regards,

Sriram