Hi Abe,<br><br>It&#39;s great to hear that you&#39;re interested in using Hokuyo intensity data.  I&#39;m not certain as to how much intensity data is being used in our point cloud processing pipelines.  I think intensity might be used in our door handle detector.  Someone else can elaborate further on this.<br>

<br>Intensity data is a critical part of the pr2_calibration stack.  We use intensity images (just like what was on the &#39;Scanner_to_camera_calibration&#39; page) to extract checkerboard corners, which is the first step in a much larger full system calibration procedure.<br>

<br><i>it seems that the values are normally somewhere between 0 and 6000. However every once in a while, they&#39;ll go as high as ~15000.</i><br>I can agree with the 0-6000 intensity estimate, but I&#39;ve definitely also seen spurious bright returns.  I haven&#39;t really paid attention to how large these returns get (maybe they are in fact ~15000), but I have noticed that the spurious bright returns occur most often when rays glance off the edges of objects.<br>

<br>


<i>it says that the intensity is a function of distance... is there a
good way to normalise out the distance factor so that intensity values
can be compared on a normalised 0 to 1 range?<br></i>I don&#39;t believe anyone here has tried to build an intensity/range model, probably because we don&#39;t have a strong use case for this type of normalization.  Somewhat related, I&#39;d be curious to see how intensity data could be used to compensate for range biases.<br>

<br>I&#39;m definitely interested in hearing how you end up using the intensity data!<br><br>Vijay<br><br><div class="gmail_quote">On Tue, Apr 13, 2010 at 4:57 PM, Abe Bachrach <span dir="ltr">&lt;<a href="mailto:abachrach@gmail.com" target="_blank">abachrach@gmail.com</a>&gt;</span> wrote:<br>


<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi there, <br>I started looking at the intensity values that you can get from the hokuyo UTM laser scanners, but was seeing a much wider fluctuation in the values than I would have expected...<br>


from looking at my own data, and the data posted on the calibration wiki<br>


<a href="http://pr.willowgarage.com/wiki/Scanner_to_camera_calibration" target="_blank">http://pr.willowgarage.com/wiki/Scanner_to_camera_calibration</a><br><br>it seems that the values are normally somewhere between 0 and 6000. However every once in a while, they&#39;ll go as high as ~15000.<br>





<br>In the documentation posted here:<br><a href="http://www.ros.org/wiki/hokuyo_node?action=AttachFile&amp;do=get&amp;target=UTM-30LX_Specification.pdf" target="_blank">http://www.ros.org/wiki/hokuyo_node?action=AttachFile&amp;do=get&amp;target=UTM-30LX_Specification.pdf</a><br>




it says that the intensity is a function of distance... is there a
good way to normalise out the distance factor so that intensity values
can be compared on a normalised 0 to 1 range?<br><br>How have you guys generally worked with the intensity info.<br><br>thanks in advance!<br><font color="#888888">-=Abe<br><br>
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