Cool, thanks for the info! At this point, not entirely sure what we'll use it for, but thought it might be useful, and we should at least be logging the info. -=Abe On Wed, Apr 14, 2010 at 11:34 AM, Radu Bogdan Rusu wrote: > I concur with what Vijay said. The intensity data was used for extracting > the door handle using statistical methods. > > Regarding intensity calibration, there's work mostly done by our colleagues > in photogrammetry and sensing > (http://www.gc.vgtu.lt/upload/geod_zurn/gc_vol35_no3_77-81_vain.pdf for > example). > > Cheers, > Radu. > > Vijay Pradeep wrote: > > Hi Abe, > > > > It's great to hear that you're interested in using Hokuyo intensity > > data. I'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. > > > > Intensity data is a critical part of the pr2_calibration stack. We use > > intensity images (just like what was on the > > 'Scanner_to_camera_calibration' page) to extract checkerboard corners, > > which is the first step in a much larger full system calibration > procedure. > > > > /it seems that the values are normally somewhere between 0 and 6000. > > However every once in a while, they'll go as high as ~15000./ > > I can agree with the 0-6000 intensity estimate, but I've definitely also > > seen spurious bright returns. I haven'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. > > > > /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? > > /I don't believe anyone here has tried to build an intensity/range > > model, probably because we don't have a strong use case for this type of > > normalization. Somewhat related, I'd be curious to see how intensity > > data could be used to compensate for range biases. > > > > I'm definitely interested in hearing how you end up using the intensity > > data! > > > > Vijay > > > > On Tue, Apr 13, 2010 at 4:57 PM, Abe Bachrach > > wrote: > > > > Hi there, > > 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... > > from looking at my own data, and the data posted on the calibration > wiki > > http://pr.willowgarage.com/wiki/Scanner_to_camera_calibration > > > > it seems that the values are normally somewhere between 0 and 6000. > > However every once in a while, they'll go as high as ~15000. > > > > In the documentation posted here: > > > http://www.ros.org/wiki/hokuyo_node?action=AttachFile&do=get&target=UTM-30LX_Specification.pdf > > < > http://www.ros.org/wiki/hokuyo_node?action=AttachFile&do=get&target=UTM-30LX_Specification.pdf > > > > 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? > > > > How have you guys generally worked with the intensity info. > > > > thanks in advance! > > -=Abe > > > > > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > -- > | Radu Bogdan Rusu | http://rbrusu.com/ > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >