Why I am getting this error message?

Error in adMedianfilter_2D (line 12)

d3x3 = window(r3, r3);

Error in adMedian (line 18)

[pixel_value, pixel_valid] = adMedianfilter_2D(c_data, c_idx); %function

Here's my code:

clc;                                      % Clear command window
clear all;                                % Delete all variables
close all;                                % Close all figure windows

I = imread('mdb001.pgm');                 %image read
J = imnoise(I,'salt & pepper',0.02);      %add noise to image
smax = 3;                                 %spatial co-variance for least neighbouring pixels
[r, c] = size(I);                         %dimensions of the image 
ll = ceil(smax/2);                        %lower-left
ul = floor(smax/2);                       %upper-left

for i = 2:r-smax                          
    for j =2:c-smax
        
        c_idx = i;
        c_data = double(I(j:j+smax-1, i));
        
        [pixel_value, pixel_valid] = adMedianfilter_2D(c_data, c_idx);     %function
        
        if pixel_valid
            J(j,i) = pixel_value;
        end
    end
end

subplot( 1, 2, 1 );
imshow( I, [  ] );
subplot( 1, 2, 2 );
imshow( J, [  ] );

%function adMedianfilter_2D
function [pixel_value, pixel_valid ] = adMedianfilter_2D( c_data, c_idx );
smax = 3;
persistent window;    %window tool

if isempty(window)
    window = zeros(smax, smax);
end

cp = ceil(smax/2); % center pixel;
w3 = -2:2;
r3 = cp + w3;      
d3x3 = window(r3, r3);
center_pixel = window(cp, cp);
outbuf = get_median_2d(d3x3);
[min3, med3, max3] = getMinMaxMed_2d(outbuf);
pixel_val = get_new_pixel(min3, med3, max3, ...
    center_pixel);
persistent datavalid
if isempty(datavalid)
    datavalid = false;
end
pixel_valid = datavalid;
datavalid = (c_idx >= smax);
end

%get_median_2d 
function outbuf = get_median_2d(inbuf)

outbuf = inbuf;
[nrows ncols] = size(inbuf);
for ii=coder.unroll(1:ncols)
    colData = outbuf(:, ii)';
    colDataOut = get_median_1d(colData)';
    outbuf(:, ii) = colDataOut;
end
for ii=coder.unroll(1:nrows)
    rowData = outbuf(ii, :);
    rowDataOut = get_median_1d(rowData);
    outbuf(ii, :) = rowDataOut;
end
end

[KSSV]

You said you are getting error. But you have not specififed what error.

[Pratiksha Joshi]

[Simon Chan]

r3 starts from 0 which is not allowed as an index.

smax = 3;
cp = ceil(smax/2); % center pixel;
w3 = -2:2;
r3 = cp + w3  

r3 = 1×5

0 1 2 3 4

Answer 1

[KSSV]

It looks like r3 is not an integer, it has decimals. Try:

r3 = round(r3) ;   % round r3 to the nearest integer 
d3x3 = window(r3, r3);