Array indices must be positive integers or logical values.

 A = imread('boat.png');
A=double(A);
[row,col]=size(A);
h=zeros(1,300);
for x=1:1:row
 for y=1:1:col
 t=A(x,y);
 % disp(t)
 h(t)=h(t)+1;
 end
end
subplot(2,1,1)
imshow(uint8(A))
title('Original Image')
subplot(2,1,2)
bar(h)
title('Histogram of the Image')

Answer 1

[the cyclist]

Your variable A is the image data.

Your variable t is the value of the image data at the (x,y) coordinate. That value of t could be equal to zero sometimes. If t==0, then this line of code

h(t)=h(t)+1;

will be equivalent to

h(0)=h(0)+1;

so you are trying to write to the "zeroth element" of the array h, which is nonexistent (and triggers the error).

[Prashant Saini]

can you please fix this error....i didn't understand what are you saying?

[the cyclist]

I don't know what your code is supposed to do, so I cannot fix it.

I suggest that you write a short paragraph explaining the purpose of the code. Then, fully comment your code, explaining what each line is supposed to do.

[Prashant Saini]

Write a Matlabcode to calculate histogram of theimage without using library function imhist ( ).

[the cyclist]

To be clear, we are not here to do your homework for you.

If you do the things I suggest, I will try to help you learn how to do your homework.

[Prashant Saini]

sorry sorry i want to fix error only

[madhan ravi]

Well, you didn't follow cyclists comments. Calculate the unique pixels sum and then use the bar function.