General Information and Help Section
This section contains general information and help on different topics concerning the ObjectModels database.
The modelling center
Minolta VI-900 scanner
Contents3D data :: Sample :: Colour stereo camera images :: XML representation :: Dowloads
The 3D data is acquired with a high-accuracy laser scanner. The objects are put on a rotation plate and turned in front of the laser scanner, and a point cloud is taken from different angles. A picture of this setting is shown to the right. The gathered 3D data is then post processed, which means registration, triangulation, cleanup and reduction. This ensures the generation of high quality meshes in different resolutions.
- Scanner information:
- Minolta "VI-900"
- Type of measurement: active triangulation
- Resolution: 640 x 480
- Accuracy: less than 0.2 mm
- Number of measurement points: 307200 (in the applied mode)
- 3D data is provided in different formats:
- Raw aligned mesh data as Rapidform model file (.mdl)
- Wavefront OBJ format (.obj)
- VRML V1.0 format (.wrl)
- and different resolutions:
- XXX_Orig.(obj|wrl|mdl) - this is the original resolution, usually between 200,000 and 400,000 faces
- XXX_25k.(obj|wrl) - this is a reduced version to approximately 25,000 faces
- XXX_5k.(obj|wrl) - this is a reduced version to approximately 5,000 faces
- XXX_800.(obj|wrl) - this is the lowest resolution at approximately 800 faces
The sample below is a short movie demonstrating a object digitized with our system. The movie was rendered with Blender using the internal raytracer and the medium resolution version of the object with approx. 5000 triangles.
Like the 3D data, the colour stereo camera images are taken from different angles. In this case, both the object can be rotated, and the camera system is mounted to a rotating bracket which can turn up and down (between about 0 and 90 degrees, compared to a level angle). This allows us to get views e.g. into a cup from above. The cameras are shown to the right.
Marlin stereo cameras
- Unless noted otherwise, objects images were retrieved with the following rotation ranges and stepwidths:
- 360 degree horizontal rotation range, 10 degree stepwidth (of the rotation plate)
- 90 degree vertical rotation range, from minimum 0 degrees to maximum +90 degrees, with a 10 degree stepwidth (of the rotation bracket with the stereo camera system)
- The preview image is a lower quality JPEG-image. The camera images in the zipped file are high quality, LZW-compressed TIFF-images in RGB8 data format as well as PNG-images with a resolution of 1392 x 1038 pixels.
- Stereo camera information:
- Allied Vision Technologies "Marlin 145C2"
- Resolution: 1392 x 1038 pixels (for the images in the database)
- Intrinsic and stereo calibration data files can be downloaded here
Along with the 3D and image data additional information about the object and the digitization process is provided in form of an XML file. Currently this only contains the filenames of the scans and images along with camera positions for each image. This will be improved in the future to contain other information like material and weight.
At this point the XML file is a representation of the digitization process. The system provides the possibility to acquire 3D data in form of scans and image data through the cameras. The following is a description of the tags used:
- Object: encapsulates a whole object consisting of several jobs
- Name: Name of the object
- TranslationRotaryPlate: Translation from object origin to object floor plane (x/y/z).
- Images: encapsulates all of the image data blocks
- Camera: left or right camera (values: "left"|"right")
- R1...R9: Rotation parameters for camera position (3x3 matrix where R1 is top left, R4 is middle left, R7 is lower left)
- TransX|Y|Z: Translation parameters for camera position
- LightFront|Back|Center: Brightness of the 3 different lightsources, front, back, center (in percent, 0-100)
A sample C++ implementation for parsing the XML job files and grasp files can be downloaded here.