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		<title>Nikon Rumors Forum &#187; Topic: Downsampling Image Best Practice</title>
		<link>http://nikonrumors.com/forum/topic.php?id=4877</link>
		<description>where there’s smoke there’s forum fire</description>
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		<pubDate>Thu, 23 May 2013 21:47:50 +0000</pubDate>
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		<item>
			<title>dormant on "Downsampling Image Best Practice"</title>
			<link>http://nikonrumors.com/forum/topic.php?id=4877#post-79036</link>
			<pubDate>Thu, 09 Feb 2012 12:40:36 +0000</pubDate>
			<dc:creator>dormant</dc:creator>
			<guid isPermaLink="false">79036@http://nikonrumors.com/forum/</guid>
			<description><blockquote><p><cite>NSXType-R <a href="http://nikonrumors.com/forum/topic.php?id=4877#post-78903">said</a>:</cite><br />
You can use MATLAB for photos too?
</p></blockquote>
<p>Of course. An image is just three (or four) matrices of numbers.</p>
<p>Basic MATLAB has some image functionality, but they also sell an Image Processing Toolbox with more bells and whistles. These are not really aimed at photographers, and don't have a nice user-friendly interface or workflow.</p>
<p>But, if you have the time, it is great for things you can't do otherwise. </p>
<p>For instance, I wanted to see how much my camera and tripod moved if I took a series of frequent time-lapse photos. So I wrote some MATLAB code to do the following analysis of a bunch of RAW images in a directory.</p>
<p>- Present the first image in a gui and select a small area for analysis (one with strong edges in it).<br />
- Crop every photo to that area.<br />
- Convert photos to greyscale.<br />
- Do a histogram stretch to increase contrast.<br />
- Do a 2D cross-correlation comparing each photo with the first photo.</p>
<p>This showed that the camera moved by one or two pixels when taking 100 shots at 10 second intervals.
</p></description>
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		<item>
			<title>NSXType-R on "Downsampling Image Best Practice"</title>
			<link>http://nikonrumors.com/forum/topic.php?id=4877#post-78903</link>
			<pubDate>Wed, 08 Feb 2012 17:45:08 +0000</pubDate>
			<dc:creator>NSXType-R</dc:creator>
			<guid isPermaLink="false">78903@http://nikonrumors.com/forum/</guid>
			<description><p>You can use MATLAB for photos too?
</p></description>
		</item>
		<item>
			<title>dormant on "Downsampling Image Best Practice"</title>
			<link>http://nikonrumors.com/forum/topic.php?id=4877#post-78879</link>
			<pubDate>Wed, 08 Feb 2012 12:50:58 +0000</pubDate>
			<dc:creator>dormant</dc:creator>
			<guid isPermaLink="false">78879@http://nikonrumors.com/forum/</guid>
			<description><p>Up until now, I've just used the default down-sampling in GIMP or whatever image-editing software I am using, assuming it takes care of things properly.</p>
<p>As a D800E pre-owner, I probably need to think more about downsampling. I use MATLAB for my work (not on images), and it has a lot of tools and stuff I can play with to experiment.
</p></description>
		</item>
		<item>
			<title>Yetibuddha on "Downsampling Image Best Practice"</title>
			<link>http://nikonrumors.com/forum/topic.php?id=4877#post-78853</link>
			<pubDate>Wed, 08 Feb 2012 10:13:55 +0000</pubDate>
			<dc:creator>Yetibuddha</dc:creator>
			<guid isPermaLink="false">78853@http://nikonrumors.com/forum/</guid>
			<description><p>With the release of the D800/800E there has been a lot of mention of downsampling to improve image quality. So how do NR enthusiasts do the downsampling? What is best practice?
</p></description>
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