Undefined function or method 'filter'

hi i am getting an error in this code

   %  function y = filtdn(x, f, dim, extmod, shift)
  % FILTDN   Filter and downsample (by 2) along a dimension
  %
  %       y = filtdn(x, f, dim, extmod, shift)
  %
  % Input:
  %   x:      input signal
  %   f:      1-D filter
  %   dim:    the processing dimension
  %   extmod: extension mode (e.g. 'per' or 'sym')
  %   shift:  specifies the window over which filtering occurs
  %
  % Output:
  %   y:      filtered and dowsampled signal
  %
  % Note:
  %   The origin of the filter f is assumed to be floor(size(f)/2) + 1.
  %   Amount of shift should be no more than floor((size(f)-1)/2).

% Skip singleton dimension
if size(x, dim) == 1    
    y = x;
    return
end

% Cell array of indexes for each dimension
nd = ndims(x);
I = cell(1, nd);
for d = 1:nd
    I{d} = 1:size(x,d);
end

% Border extend
n = size(x, dim);
hlf = (length(f) - 1) / 2;
% Amount of extension at two ends
e1 = floor(hlf) + shift;
e2 = ceil(hlf) - shift;

switch extmod
    case 'per'
        I{dim} = [ly-e1+1:n , 1:n , 1:e2];

      case 'sym'
          I{dim} = [e1+1:-1:2 , 1:n , n-1:-1:e2];

      otherwise
          error('Invalid input for EXTMOD')

end
y = x(I{:});

% Filter, downsample, and return only the 'valid' part
y = filter(f, 1, y, [], dim);

I{dim} = (1:2:n) + length(f) - 1;
y = y(I{:});

and the error is ??? Undefined function or method 'filter' for input arguments of type 'uint8'.

Error in ==> filtdn at 54 y = filter(f, 1, y, [], dim);

Filter is an inbuilt function and i have image processing toolbox installed and set in my preferrence ...

can anyone help me with this???

[rani krithiga]

can you tell me parameters for all functions in lpdemo.m

[Walter Roberson]

rani krithiga,

Are you asking about https://www.mathworks.com/matlabcentral/fileexchange/9868-laplacian-pyramid-toolbox/content/lpdemo.m ?? That would not appear to have anything to do with the current Question; please open a new Question about that. Did you look at the comments in the source code for each function?

Answer 1

[Walter Roberson]

filter() does not accept arguments of datatype uint8(). You need to filter a single precision or double precision value.

[Mani]

thanks...

Answer 2

[Andreas Goser]

This likely is an overload of multiple FILTER commands. Try

which filter -all

In my installation, it returns:

built-in (C:\Program Files\MATLAB\R2012a\toolbox\matlab\datafun\@single\filter)    % single method
built-in (C:\Program Files\MATLAB\R2012a\toolbox\matlab\datafun\@double\filter)    % double method
C:\Program Files\MATLAB\R2012a\toolbox\simulink\simulink\@SigLogSelector\filter.m  % SigLogSelector method
C:\Program Files\MATLAB\R2012a\toolbox\comm\comm\@gf\filter.m                      % gf method
C:\Program Files\MATLAB\R2012a\toolbox\comm\comm\@channel\filter.m                 % channel method
C:\Program Files\MATLAB\R2012a\toolbox\econ\econ\@LagOp\filter.m                   % LagOp method
C:\Program Files\MATLAB\R2012a\toolbox\dsp\filterdesign\@mfilt\filter.m            % mfilt method
C:\Program Files\MATLAB\R2012a\toolbox\dsp\filterdesign\@adaptfilt\filter.m        % adaptfilt method
C:\Program Files\MATLAB\R2012a\toolbox\finance\ftseries\@fints\filter.m            % fints method
C:\Program Files\MATLAB\R2012a\toolbox\fixedpoint\fixedpointtool\@fxptui\filter.m  % fxptui method
C:\Program Files\MATLAB\R2012a\toolbox\mbc\mbctools\@sweepsetfilter\filter.m       % sweepsetfilter method
C:\Program Files\MATLAB\R2012a\toolbox\mbc\mbctools\@sweepset\filter.m             % sweepset method
C:\Program Files\MATLAB\R2012a\toolbox\signal\signal\@dfilt\filter.m               % dfilt method
C:\Program Files\MATLAB\R2012a\toolbox\matlab\timeseries\@timeseries\filter.m      % timeseries method

Please see what is at the top for you and consider renaming.

[Mani]

hi ... thanks for the reply ....

if i want to use a filter of type FILTER(B,A,X,[],DIM) what do i do . It is a built in function

my installation returns

built-in (D:\Program Files\Matlab\toolbox\matlab\datafun\@single\filter) % single method

built-in (D:\Program Files\Matlab\toolbox\matlab\datafun\@double\filter) % double method

D:\Program Files\Matlab\toolbox\matlab\timeseries\@timeseries\filter.m % timeseries method

D:\Program Files\Matlab\toolbox\comm\comm\@gf\filter.m % gf method

D:\Program Files\Matlab\toolbox\comm\comm\@channel\filter.m % channel method

D:\Program Files\Matlab\toolbox\econ\econ\@LagOp\filter.m % LagOp method

D:\Program Files\Matlab\toolbox\filterdesign\filterdesign\@mfilt\filter.m % mfilt method

D:\Program Files\Matlab\toolbox\filterdesign\filterdesign\@adaptfilt\filter.m % adaptfilt method

D:\Program Files\Matlab\toolbox\finance\ftseries\@fints\filter.m % fints method

D:\Program Files\Matlab\toolbox\fixedpoint\fixedpointtool\@fxptui\filter.m % fxptui method

D:\Program Files\Matlab\toolbox\mbc\mbctools\@sweepsetfilter\filter.m % sweepsetfilter method

D:\Program Files\Matlab\toolbox\mbc\mbctools\@sweepset\filter.m % sweepset method

D:\Program Files\Matlab\toolbox\signal\signal\@dfilt\filter.m % dfilt method

Answer 3

[Jan]

The error message means, that f must not be a uint8 vector. Simply convert it to a double.

[Mani]

I am still getting the same error... do i have to convert vector y too???

[Mani]

thanks... your answer too helped me sort out the problem...