ofxActiveScan

Naoto Hieda micuat@gmail.com, 09 July 2013

About

This repository is an openFrameworks addon for active 3D scanning for uncalibrated projector-camera system. While this repository takes ofxaddon-style, you can start 3D scanning just by compiling the included example projects.

3D scanning algorithm is heavily relying on the software provided by Dr. Shuntaro Yamazaki and visualization is inspired by ProCamToolkit.

Dependencies

• ofxOpenCv
• ofxCv
  • required for example_triangulate and Kinect examples
• ofxKinect
  • required for Kinect examples

Data Folder

In ofxActiveScan examples, a data folder stores all information of a projector-camera pair, including calibration parameters and a point cloud.

In order to specify the data folder, just drag the folder icon to the openFrameworks window. The folder path can be specified by a command-line argument as well.

To begin with, only the file config.yml must be created in the folder. Look for myData for an example.

First, use example-encode to capture structured-light images, then, example-calibrate to solve camera parameters, and finally, example-triangulate to reconstruct a point cloud.

config.yml

Set parameters for example projects:

• proWidth/proHeight/camWidth/camHeight
  • specify projector/camera image size
• grayLow/grayHigh
  • specific to example-encode
  • black and white value for structured light (0-255; grayLow currently ignored)
  • grayHigh must be carefully adjusted to avoid saturation
• devID
  • specific to example-encode
  • device ID of the camera
• bufferTime
  • specific to example-encode
  • buffer time for structured light capturing (milliseconds)
  • set longer when camera buffer is too long
• vertical_center
  • y value of the principal point of the projector divided by image height (0: top of the image, 1: bottom)
  • can be calculated from parameters in a user manual of the projector
    • 0.83 for EMP765
    • 0.92 for EMP1735W 16:9
    • 0.87 for EMP1735W 16:10
    • 0.86 for EMP1735W 4:3
    • 1.12 for XD490U 4:3

example_encode

This app projects and captures structured light patterns. [f] to toggle fullscreen and [space] to start capturing. The app window must be set fullscreen on the projector desktop before starting.

An image is saved for colored point cloud to camPerspective.jpg.

After scanning, the result is decoded and following files are saved: h.map, v.map, mask.png, reliable.png

example_calibrate

This app solves camera/projector intrinsic parameters and extrinsic paramters from the example_encode outputs. Calibration results are saved to calibration.yml.

example_triangulate

Finally, this app reconstructs a 3D point cloud. The point cloud is saved to out.ply. Press [1] to view the point cloud, [2] to view the projector perspective and [3] to camera perspective.

License

This software is provided under the terms of the GNU General Public License.