How to plot PDF and CDF an image with Rayleigh distribution?

Hello, I have an gray image. Now i want plot CDf and PDF with Rayleigh distribution. But i can't.

clc
clear all
close all

   R = imread('cameraman.tif');
  R = imhist(R);
  pR = raylpdf(R,10);
 cR = raylcdf(R,10);