Same question as Stefan - has anyone thought of a calibration procedure between the depth and range camera? Ivan On Fri, Nov 12, 2010 at 3:19 AM, Stefan Kohlbrecher wrote: > Nice, that already looks pretty good. Do you have the same ~4cm > vertical offset between color and depth data? > http://img717.imageshack.us/img717/3955/kinectrviztrevor.png > It's pretty visible when looking at the screen in the lower portion. > I'm well aware that this is basically uncalibrated, my question is > more directed towards the variability of alignment between different > Kinect devices. > > 2010/11/12 Alex Trevor : >> Apologies for the broken github link, the correct one is: >> https://github.com/atrevor/kinect_node.git >> On Fri, Nov 12, 2010 at 2:20 AM, Alex Trevor wrote: >>> >>> Wow, looks like quite a few people are working on kinect nodes; we should >>> probably combine efforts!  We’ve also been working on a kinect node for ROS >>> based on Hector Martin’s driver, available at: >>> git://github.com/atrevor/kinect_node.git >>> >>> Short youtube rviz screencap: >>> http://www.youtube.com/watch?v=IxRIL1izvDs >>> >>> We assume that you have libfreenect from Hector Martin’s repo in the same >>> parent directory (../libfreenect w.r.t. kinect_node): >>> git://git.marcansoft.com/libfreenect.git >>> >>> So far, it publishes the camera image, as well as a PointCloud2 of >>> PointXYZRGBs.  The RGB camera’s image is projected onto the range data, >>> resulting in a color point cloud.  We calibrated the RGB camera, but haven’t >>> yet calibrated the range camera -- since we can’t just use our normal >>> checkerboard calibration target for this :) .  As Ivan and Stefan noted, the >>> ranges we get are a little odd -- they definitely don't seem to be linear. >>>  We calibrated it so the range is approximately correct at 2m for our >>> sensor, but I agree that we really need to know how these work to make much >>> progress. We'll probably do some testing shortly with targets at various >>> ranges to attempt to address this.  Any input would be greatly appreciated! >>> On Thu, Nov 11, 2010 at 5:41 PM, Stefan Kohlbrecher >>> wrote: >>>> >>>> > 1. Is the depth image really 640x480, or is that oversampled? The >>>> > wikipedia page states the depth sensor has an resolution of 320×240 >>>> > pixels. If it's oversampled, where does that take place - in the >>>> > driver, or the device itself? I prefer not inflating the point cloud >>>> > with oversampled data >>>> I think the device itself reports the data with this size. If you look >>>> at the picture I posted in the second post you also see that there are >>>> for example one pixel sized holes in the 640x480 sized depth image, >>>> which should not exist if some very simple interpolation scheme would >>>> be used to blow up a 320x240 image to 640x480. >>>> From what I read beforehand, the original Project Natal was supposed >>>> to be 640x480, then Microsoft reportedly "downgraded" to 320x240 for >>>> cost reasons (see >>>> >>>> http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=kinect+downgraded+to+320x240). >>>> Now the sensor appears to deliver 640x480 again, which might or might >>>> not be just blown up 320x240on the onboard ASIC. >>>> >>>> > 2. What is the relationship between the values in the depth_frame and >>>> > the distance in meters? It doesn't appear to be linear >>>> That´s really the interesting question, along with others like how to >>>> calibrate visual and depth image to get real RGB-D data. With the >>>> current state of affairs one can generate some impressive looking >>>> images, but to leverage the full potential of the sensor these >>>> calibration questions really have to be solved. >>>> >>>> > 3. I read somewhere the device's range can be set dynamically. I'm >>>> > guessing one of the inits in inits.c could be responsible for the >>>> > range. >>>> That´s more stuff that will probably be discovered in the coming >>>> days/weeks. Still very impressive how good the sensor works already >>>> right out of the box. >>>> >>>> > _______________________________________________ >>>> > 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 >>> >> >> >> _______________________________________________ >> 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 >