i have problem with : Attempted to access C(0); index must be a positive integer or logical. Error in HistogramEkualisasi (line 24)

"Error in HistogramEkualisasi (line 24)
 hasil(baris, kolom) = C(Img(baris, kolom));"

Img = imread('D:\Pengolahan Citra Digital\Program MATLAB\car.jpg');
ukuran = size(Img);
jum_baris = ukuran(1);
jum_kolom = ukuran(2);

L = 256;
histog = zeros (L, 1);
for baris=1 : jum_baris
    for kolom=1 : jum_kolom
        histog(Img(baris, kolom)+1) = ...
            histog(Img(baris, kolom)+1) +1;
    end
end

alpha = (L-1) / (jum_baris * jum_kolom);

C(1) = alpha * histog(1);
for i=1 : L-1
    C(i+1) = C(i) + round(alpha * histog(i+1));
end

for baris=1 : jum_baris
    for kolom=1 : jum_kolom
        hasil(baris, kolom) = C(Img(baris, kolom));
    end
end

hasil = uint8(hasil);
imshow(hasil);

Answer 1

[Walter Roberson]

Some of your counts will be 0, so Img(baris, kolom) will sometimes be 0. You are trying to index C(Img(baris, kolom)) so you are trying to index C(0) which is not permitted.

For consistency with your earlier code you should be referring to C(Img(baris,kolom)+1)

[yusuf zain]

thanks, but why when i tried to run this program, the image full black

[Walter Roberson]

With the test image that I used, I do not get an all-black result.

Note that you read in a .jpg image. .jpg images are almost always RGB images, but you ignore everything except what corresponds to the red color plane. If the red color plane is empty you would not get anything useful out.