三维直方图更直观，借助matlab的bar3，可以绘制三维直方图。 

clc;
clearvars;
c=imread('lena.jpg');
width =0.8;   %默认值是0.8，根据需要修改。
% h=bar3(c,width,'r');
h=bar3(c);
set(h,'EdgeColor','r')
% set(h,'facecolor','b')
% set(h(1),'facecolor','red') % use color name
% set(h(2),'facecolor',[0 1 0]) % or use RGB triple
% set(h(3),'facecolor','b') % or use a color defined in the help for PLOTx=imread('cipher.jpg');
figure;
xh=bar3(x);
set(xh,'EdgeColor','b');