OVERLAY OF HISTOGRAMS error in variables

im trying to overlay to histograms in one graph, but i have this error taht i cant understand.

   x = handles.grey;
   y = handles.binaria

   nbins = 50;
   bound = 1;
  bins = linspace(-bound,bound,nbins);

% %b = histeq(X);
% first histogram
y1 = hist(x, bins);
% second histogram
y2 = hist(y, bins);

% overlay histograms
bar(y1.');
hold on;
bar(y2.','r');

the error given is

Error using hist (line 48)
Input arguments must be numeric.

Error in untitled>histograma_Callback (line 112)
y2 = hist(y, bins);

y is a black and white image, binary, it was converted to double, however it doesnt work. thank you!

Answer 1

[Image Analyst]

What does this say

whos y

Also, maybe you can try imhist(), histogram(), or histcounts().

Anyway, it makes no sense to have 50 bins, or actually bin edges which is what you're passing in, for a binary image. You will have no counts except in the bins for 0 and 1.

[Sofia Cirne]

Y is the binary image.I took some code from the Web, I've tried several ones but always gives me the same mistake

[Image Analyst]

Are you going to answer my question about "whos y", or not?

And, like I said, use imhist() and the problem should go away.

counts = imhist(y);
bar(counts, 'BarWidth', 1)

[aditya sahu]

are you trying for pdh analysis