National Institute of Standards and Technology

Dynamic Geodesic Measurements Using Kinect Cameras

Summary

With the availability of inexpensive Kinect depth cameras, questions arise about accuracy of depth measurements from these cameras for scientific purposes. We quantified the uncertainty of depth values within the dynamic range of Kinect camera.

The calculation of geodesic measurements has a wide range of applications, including applications in the medical field, material science field and machine vision field. We aimed at quantifying the accuracy of geodesic measurements (distance and area) on a variety of objects including rigid, deformable, articulated and non-articulated objects.

Kinect calibration
calibration object built from Lego for quantifying the uncertainty of depth values within the dynamic range of Kinect camera.

Kinect calibration
Standard deviation of depth difference measurements for the calibration object (front and back planes) as a function of distance from the camera.

Description

A Lego model of a calibration object was constructed with two parallel flat surfaces that were separated by 64 mm (see Figure 1). The calibration process consists of moving the Lego model away from the Kinect along the depth axis, correcting for its tilt, detecting the frontal and posterior parallel planes, and plotting the difference between detected planes against the measured depth value. Figure 2 shows the measurements over a range of 0.5m to 3.5m.

In addition, we focused on developing software that would assist in measuring geodesic distance and area of human body parts using Kinect camera. The application scenarios include tracking geodesic measurements on a moving deformable object, particularly a human, and measuring geodesic distance and area on a three dimensional model of a rotating rigid object. These application scenarios need components for spatial detection, object tracking, coordinate transformation, and three dimensional reconstruction.

Lead Organizational Unit:

ITL

Staff:

ITL-Software and Systems Division
Information Systems Group
  • Mary Brady
  • Peter Bajcsy
  • Jacob Siegel, SURF student from University of Maryland at College Park
  • Colin Richman, SHIP student from Poolsville High Schoool, MD

Contact:

Date created: April 10, 2014 | Last updated: