OniExtractor

Extract images and real world coordinates from OpenNI oni-files to OpenCV Matrices.

Dependencies

• OpenNI 1.5.x
• OpenCV

Usage

The OniExtractor class can be used to write frames extracted from a given .oni file to std::vector<cv::Mat>.

    OniExtractor oe(filename);
    bool ok = oe.init();

You can extract the RGB images (CV_8UC3), depth images (CV_16U), real world coordinates (CV_32FU3) and timestamps (in milliseconds).

    std::vector<cv::Mat> img, depth, world;
    std::vector<unsigned long> ts;
    oe.extract();
    oe.getRGB(img);
    oe.getDepth(depth);
    oe.getWorldCoords(world);
    oe.getTimestamps(ts);

Additionally you can specify timestamps of interest and a margin to extract only frames at the specified timestamps within the margin. Each time value is given in milliseconds.

    std::vector<unsigned long> tsoi = {1000, 2000, 3000};
    margin = 100;
    oe.setTimestampsOfInterest(tsoi, margin);
    
    

If your timestamps of interest are absolute (i.e., Unix) timestamps, you can specify a reference time, e.g., the creation time of the .oni file.

    unsigned long ref = 946684800000; // year 2000
    oe.setAbsoluteTimestampReference(ref);
    oe.setTimestampsOfInterest({946684801000, 946684802000, 946684803000}, 100);
    

Acknowledgment

... goes to Pieter Eendebak for this post, Dirk-Jan Kroon and M. Lang.