Hi Matei, two more questions: 1. are the objects in /opt/ros/cturtle/stacks/simulator_gazebo/gazebo_worlds/meshes compatible with the matching algortihm in tabletop_object_detector? 2. for testing the recognition algorithm, how easy is it to transform the meshes back to pointclouds and deliberately alter them a bit? Regards, Rene 2010/7/14 Matei Ciocarlie : > Hi Renee, > > For now you will have to add models to the database by hand - we will > have some tutorials coming out probably next week on how to do that. > > Matei > > On Wed, Jul 14, 2010 at 3:14 AM, René Ladan wrote: >> Hi, >> >> is there currently any node available to input custom models? >> The model_assembler node seems to have vanished in thin air. >> >> Regards, >> Rene >> >> 2010/7/13 Matei Ciocarlie : >>> That's hard to quantify precisely... I would say that you should not >>> worry about precision too much, any reasonably lifelike mesh will do. >>> >>> It also depends what else is in the database of models: if you only >>> have your own models, then only those will be fitted against. You will >>> be able to recognize fewer objects, but at least other models will not >>> get in the way. You can also play with the thresholds in >>> tabletop_object_detector/src/tabletop_node.cpp to make the recognition >>> more forgiving. >>> >>> Matei >>> >>> On Tue, Jul 13, 2010 at 9:24 AM, René Ladan wrote: >>>> Hi Matei, >>>> >>>> I get it now ;) >>>> >>>> If I want to model my own objects (for any reason), how precise and >>>> complete must the triangle meshes be for the object detection to work? >>>> >>>> Regards. >>>> Rene >>>> >>>> 2010/7/13 Matei Ciocarlie : >>>>> Hi Rene, >>>>> >>>>> The models are stored in the database as triangle meshes. For display, >>>>> we found it more clear to render them as wireframe rather than >>>>> triangle meshes, as the wireframe still allows the original point >>>>> cloud to show trough a little bit. >>>>> >>>>> The detection is done by comparing the perceived point cloud against >>>>> the triangle mesh stored in the database. >>>>> >>>>> Best, >>>>> Matei >>>>> >>>>> On Tue, Jul 13, 2010 at 9:03 AM, René Ladan wrote: >>>>>> Hi Matei, >>>>>> >>>>>> so the wireframe is only used for display reasons and to store the models >>>>>> more efficiently in the database. Is the detection then realized by comparing >>>>>> perceived pointcloud with the pointcloud version of the database models? >>>>>> >>>>>> Regards, >>>>>> Rene >>>>>> >>>>>> 2010/7/13 Matei Ciocarlie : >>>>>>> Hi Rene, >>>>>>> >>>>>>> That's generally correct, except for the transformation of the point >>>>>>> cloud into wireframe. The tabletop_object_detector uses sensor data >>>>>>> directly as point clouds. You might see a wireframe displayed on the >>>>>>> screen but that's only after a database model has been recognized. The >>>>>>> wireframe is that of the model, superimposed on the point cloud that >>>>>>> has been recognized. >>>>>>> >>>>>>> Matei >>>>>>> >>>>>>> On Tue, Jul 13, 2010 at 4:59 AM, René Ladan wrote: >>>>>>>> Hi, >>>>>>>> >>>>>>>> below is a text I intend to include in a report. Do I get the basic ideas right? >>>>>>>> >>>>>>>> Regards, >>>>>>>> Rene >>>>>>>> >>>>>>>> Object handling consists of several steps, which are performed by the >>>>>>>> tabletop_object_detector (and other) nodes. >>>>>>>> •       Get an image of the object (e.g. a pool ball) from e.g. a stereo >>>>>>>> camera with texturing or e.g. a laser range finder. >>>>>>>> •       Transform the image (either a stereo-photo or a “sphere” of >>>>>>>> distances) into a point cloud. A point cloud is a collection of >>>>>>>> points, where all points have a number of pre-defined attributes, like >>>>>>>> spatial coordinates, color, or neighborhood density. Point clouds are >>>>>>>> the universal data structures for performing 3-dimensional algorithms >>>>>>>> within ROS. TODO: figure out the algorithm >>>>>>>> •       Transform the point cloud into a wireframe. TODO: figure out which >>>>>>>> algorithm is used for this. >>>>>>>> •       Now that an approximate wireframe model of the object is available, >>>>>>>> (because the camera images are probably imperfect), this model can be >>>>>>>> compared to a database of existing, perfect wireframe models. Because >>>>>>>> the models are stored as blobs in the database, the approximation is >>>>>>>> done in the ROS node. The database is thus only used a storage >>>>>>>> backend. >>>>>>>> •       The comparison algorithm, given the actual model at one side and the >>>>>>>> database models at the other side, is able to calculate the likelihood >>>>>>>> that the presented object matches a or multiple objects in the >>>>>>>> database (e.g. for a ping-pong ball, it could say “90% pool ball, 8% >>>>>>>> bottle cap, and 2% unknown”). >>>>>>>> >>>>>>>> -- >>>>>>>> http://www.rene-ladan.nl/ >>>>>>>> >>>>>>>> GPG fingerprint = E738 5471 D185 7013 0EE0  4FC8 3C1D 6F83 12E1 84F6 >>>>>>>> (subkeys.pgp.net) >>>>>>>> _______________________________________________ >>>>>>>> ros-users mailing list >>>>>>>> ros-users@code.ros.org >>>>>>>> https://code.ros.org/mailman/listinfo/ros-users >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Matei Ciocarlie >>>>>>> Research Scientist >>>>>>> Willow Garage Inc. >>>>>>> 650-475-9780 >>>>>>> _______________________________________________ >>>>>>> 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 >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Matei Ciocarlie >>>>> Research Scientist >>>>> Willow Garage Inc. >>>>> 650-475-9780 >>>>> _______________________________________________ >>>>> 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 >>>> >>> >>> >>> >>> -- >>> Matei Ciocarlie >>> Research Scientist >>> Willow Garage Inc. >>> 650-475-9780 >>> _______________________________________________ >>> 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 >> > > > > -- > Matei Ciocarlie > Research Scientist > Willow Garage Inc. > 650-475-9780 > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >