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 >