detecting features on a big image object

Hi,

I would like to ask some help for detecting SURF features on a big image object.

I use MATLAB2020b.

Code:

% Creat a big image object

bigIm = bigimage('my_geotiff_image');

% Convert it to grayscale

bigIm = getFullLevel(bigIm,bigIm.CoarsestResolutionLevel);

bigIm = rgb2gray(bigIm);

% Trying feature detection

refImPoints = apply(bigIm,1,@(block)detectSURFFeatures(block));

Error:

Undefined function 'apply' for input arguments of type 'function_handle'.

I would be greatful if we solve the problem:)

Answer 1

[Ameer Hamza]

The input to apply() must also be a bigImage, and there are also some conditions on how to define the function handle as stated in the documentation: https://www.mathworks.com/help/images/ref/bigimage.apply.html#mw_4a662881-8964-426a-b268-1ad3b09e911d. Try following code

bigIm = bigimage('my_geotiff_image');
% Convert it to grayscale
bigIm = getFullLevel(bigIm,bigIm.CoarsestResolutionLevel);
bigIm = rgb2gray(bigIm);
bigIm = bigimage(bigIm);
% Trying feature detection
refImPoints = apply(bigIm,1,@(block){detectSURFFeatures(block)});

[Miklós Förster]

Thank you a lot for your quick answer, it works!

[Ameer Hamza]

I am glad to be of help!!!