help me solve this error detectSURFFeatures

i am having following sample code: I = imread('box.jpg'); points = detectSURFFeatures(I);

    imshow(I); hold on;
    plot(points.selectStrongest(10));
i am getting this error:
Error using detectSURFFeatures
Expected input number 1, I, to be two-dimensional.

Error in detectSURFFeatures>parseInputs (line 130) validateattributes(I,{'logical', 'uint8', 'int16', 'uint16', ...

Error in detectSURFFeatures (line 81) [Iu8, params] = parseInputs(I,varargin{:});

Error in Untitled3 (line 2) points = detectSURFFeatures(I); pls help me solve this.

Answer 1

[Dima Lisin]

detectSURFFeatures only works on grayscale images. Use rgb2gray to convert I to grayscsle.

[india king]

the image is already in grayscale

[india king]

thank you.It worked. although the image was in grayscale i had to convert it once againg using rgb2gray fn and the code works now.

[Dima Lisin]

It is about the size. The image may look gray, but if its size is MxNx3, it is still RGB, as far as function is concerned.

Answer 2

[Anand]

What does class(I) return? If it does not return one of the following, your image is not of the right type:

'logical', 'uint8', 'int16', 'uint16', 'single', 'double'

[india king]

it returns uint8.

Should i check for any additional installed packages?