利用Matlab实现图像亮度分布统计图

写了一个输入图片，便会生成美观的图像各通道亮度分布图的函数，大概效果如下：

老样子，工具函数放在最前面，之后会介绍咋用这个函数：

工具函数

function histogrampic(pic)
freqnum=zeros(size(pic,3),256);
for i=1:size(pic,3)
    for j=0:255
        freqnum(i,j+1)=sum(sum(pic(:,:,i)==j));
    end
end
ax=gca;hold(ax,'on');box on;grid on
if size(freqnum,1)==3
    bar(0:255,freqnum(1,:),'facecolor',[0.6350 0.0780 0.1840],'facealpha',0.5);
    bar(0:255,freqnum(2,:),'facecolor',[0.2400 0.5300 0.0900],'facealpha',0.5);
    bar(0:255,freqnum(3,:),'facecolor',[0      0.4470 0.7410],'facealpha',0.5);
    ax.xlabel.string='rgb brightness';
    rrange=[num2str(min(pic(:,:,1),[],[1,2])),' , ',num2str(max(pic(:,:,1),[],[1,2]))];
    grange=[num2str(min(pic(:,:,2),[],[1,2])),' , ',num2str(max(pic(:,:,2),[],[1,2]))];
    brange=[num2str(min(pic(:,:,3),[],[1,2])),' , ',num2str(max(pic(:,:,3),[],[1,2]))];
    legend({['r: range[',rrange,']'],['g: range[',grange,']'],['b: range[',brange,']']},...
             'location','northwest','color',[0.9412    0.9412    0.9412],...
             'fontname','cambria','linewidth',0.8,'fontsize',11);
else 
    bar(0:255,freqnum(1,:),'facecolor',[0.50 0.50 0.50],'facealpha',0.5);
    ax.xlabel.string='gray scale';
    krange=[num2str(min(pic(:,:,1),[],[1,2])),' , ',num2str(max(pic(:,:,1),[],[1,2]))];
    legend(['gray: range[',krange,']'],...
           'location','northwest','color',[0.9412    0.9412    0.9412],...
           'fontname','cambria','linewidth',0.8,'fontsize',11);
end
ax.linewidth=1;
ax.gridlinestyle='--';
ax.xlim=[-5 255];
ax.xtick=[0:45:255,255];
ax.ylabel.string='frequency number';
ax.fontname='cambria';
ax.fontsize=13;
end

函数调用

非常简单的使用方法，就是读取图片后调用函数即可：

pic=imread('test.png');
histogrampic(pic)

若图像是彩图则效果如下：

若图像为灰度图则效果如下：

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