[原创]直方图计算公式
<P>资料宝贵，建议大家打开ps跟我去练习体会，并独立思考。<br></P><P>本帖中，前三个提问者，我会免费为之解答（进阶区的收费学生不受此限制）。<br></P>
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[align=right][color=#000066][此贴子已经被作者于2006-3-8 19:35:32编辑过][/color][/align]
<P>跟我动手做：<br></P>
<P><FONT style="BACKGROUND-COLOR: #ffff44" size=4>步骤１－６说明：利用辅助线作出精确的色块面积。</FONT></P>
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<P>１：新建８００Ｘ６００像素画布；<br></P><br>[attach]192318[/attach]<br>
[align=right][color=#000066][此贴子已经被作者于2006-3-8 16:29:56编辑过][/color][/align]
<P>２：Ctrl+R调出标尺，并如图操作；<BR></P>
[attach]192319[/attach]<BR> <P>３：参数如图设置；<BR></P>
[attach]192320[/attach]<BR> <P>４：同理操作，但选项和参数有所改变；<BR></P>
<P>[attach]192322[/attach]<BR></P>
<P>５：实例图，作参看设置检查用。<BR></P>
<P><BR> </P>[attach]192324[/attach]<BR> <P>６：用矩形选框工具，分别如图作选区，并填充相应颜色。<BR></P>
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<P>[attach]192327[/attach]<BR></P>
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<P>[attach]192328[/attach]<BR></P>
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<P>[attach]192329[/attach]<BR></P>
<P>这是实例图，作参看用。<BR></P>
<P><BR> </P>[attach]192330[/attach]<BR> <P>步骤１－６说明：利用辅助线作出精确的色块面积。</P>
这是什么意思？ <P>进入直方图面板中<BR></P>
[attach]192332[/attach]<BR> <P>下面从易到难，我们逐渐说明。<BR></P>
<P>１：色阶；把鼠标如图范围放置，色阶功能会告诉你鼠标所处于的色阶位置。<BR></P>
<P>截图中，色阶告诉我的鼠标位置在１６３处。<BR></P>
<P>１６３是怎样的一个数值？（怎样的一个概念）<BR></P>
<P>打比方说：０为最黑，１２８为中间，２５５为最亮；那么鼠标在１６３>１２８处，说明鼠标在较亮的范围上。<BR></P>
<img src="http://files.photops.com/attachments/dvbbs/2006-3/20063815313512098.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/20063815313512098.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR> <P>调不出你这种标尺</P> <P>向右或左拉动鼠标，色阶会告诉我们现在鼠标所选取分析的色阶数值。<br></P>
<P>本例为９８－１６３</P>
<P><img src="http://files.photops.com/attachments/dvbbs/2006-3/2006381535349642.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/2006381535349642.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><br><br></P><br>
[align=right][color=#000066][此贴子已经被作者于2006-3-8 16:31:05编辑过][/color][/align]
<P>还有么```</P>[em02][em02][em02] <P>还有么````还有么</P>[em02][em02] 还没写完？？？[em02][em02][em02] 正在学习 <P>输入新参考线数值后图中没有显示，只能用鼠标从边上拉出来，是不是那里要调整</P> <P>１：像素；画布是８００Ｘ６００像素，所以直方图的像素即为４８００００——这是整张图像的大小（像素）<br></P>
<P><img src="http://files.photops.com/attachments/dvbbs/2006-3/2006381557093218.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/2006381557093218.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><br></P>
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[align=right][color=#000066][此贴子已经被作者于2006-3-8 17:09:06编辑过][/color][/align]
<P>如果我们用魔术棒选择工具，选取红色，如图像素只是２４００００——即４８００００的一半（回忆一下，前面我们是如何作这个红色块面积的）<br></P>
<P><img src="http://files.photops.com/attachments/dvbbs/2006-3/2006381603986229.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/2006381603986229.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><br><br></P>
<P>（说点不相关的知识，利用此功能我们还可以简单一下求不规则图形的面积，这里略过）<br></P><br> <P>３：数量；当鼠标放置直方图中，数量功能告诉我们该点或该范围一共有多少个像素点。<BR></P>
<P><img src="http://files.photops.com/attachments/dvbbs/2006-3/20063816155086989.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/20063816155086989.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR></P>
<P>假如某个色阶处或范围里面，没有像素，那么数量值即显示为０<BR></P>
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<P><img src="http://files.photops.com/attachments/dvbbs/2006-3/2006381617384885.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/2006381617384885.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR></P>
<P><BR>这个范围内没有数量<BR></P>
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<img src="http://files.photops.com/attachments/dvbbs/2006-3/20063816184825475.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/20063816184825475.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR> <P>在１０楼图片</P>
<P>与１２楼第一张图片中，似乎存在着一个矛盾：</P>
<P>——像素与数量的矛盾！</P>
<P>全画布的大小是８００Ｘ６００＝４８００００像素</P>
<P>但数量又显示为４８００００</P>
<P>这如何理解呢？<br></P><br>１０图片<br><br><IMG src="http://files.photops.com/attachments/dvbbs/2006-3/2006381557093218.jpg" border=0><br><br><br>12楼图片<br><br><IMG src="http://files.photops.com/attachments/dvbbs/2006-3/20063816155086989.jpg" border=0><br> 原来，像素＝红＋绿＋蓝通道的数量；<BR><BR>而直方图通道ＲＧＢ里面的某个色阶处数量即是“红＋绿＋蓝（某色阶）”的数量。<BR><BR>大家可以进入通道中看看，红、绿、蓝通道的白色部分相加起来，是不是刚好等于一个完整的通道像素，是不是等于三分之一ＲＧＢ通道？<BR><BR>[attach]192396[/attach]<BR> 假如上面的说明你不能理解的话，那么我们从另一个角度来说ＲＧＢ像素＝ＲＧＢ红绿蓝三个通道数量相加。<BR><BR>比方说：现在我们现在进入蓝通道中去，在我们的电脑显示器上，直方图会自动跳到“蓝通道”选项去。<BR>刚才ＲＧＢ项，鼠标放置在２５５的数量是４８００００个，而现在进入蓝通道的２５５处是１２００００个。<BR><BR><img src="http://files.photops.com/attachments/dvbbs/2006-3/2006381655111802.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/2006381655111802.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR> <P>百分位：即是１２００００/４８００００＝２５％</P>
强的离谱。。我是菜鸟应该是看不懂的。但感觉强悍。呵呵。问题的话以后有别的要问你的哈，记得欠我问题啊。呵呵 <P>刚刚的发言太急噪了```恩``我是刚学不久的```能不能告诉我这些和什么有关`````我算是第一个发贴的吧````你说的哦</P>[em01][em01][em01] 下面将从易到难来讲解直方图。<br><br>首先进入直方图的亮度中，本例以亮度项来讲解。<br><br>１：<FONT style="BACKGROUND-COLOR: #d7f076" size=4>像素＝全画布大小</FONT>（８００Ｘ６００＝４８００００）<br><br>[attach]192406[/attach]<br><br>或者＝<FONT size=4><FONT style="BACKGROUND-COLOR: #e0f394">选择区域大小</FONT><br></FONT><br><br>[attach]192408[/attach]<br>
<P> 还是看不懂.....昏饿...</P> 色阶就是鼠标在直方图所处于的位置<BR><BR><img src="http://files.photops.com/attachments/dvbbs/2006-3/20063817322452247.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/20063817322452247.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR><BR><BR><img src="http://files.photops.com/attachments/dvbbs/2006-3/20063817323344864.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2006-3/20063817323344864.jpg\');}" onmousewheel="return imgzoom(this);" alt="" /><BR> 色阶：鼠标所处于直方图的位置；<BR><BR>数量：某个色阶位置中，有多少像素；<BR><BR>百分比：这些像素占全画布像素的百分之几；<BR><BR>下两图可以这样读解：<BR>１：当前鼠标处于的色阶位置是１５０（或185）中，数量是１２００００（或０）个，占全画布像素的２５％（或０）<BR><BR>[attach]192434[/attach]<BR><BR><BR>[attach]192435[/attach]<BR>