Elphel Development Blog

Photogrammetric Calibration of the Quad Thermal Camera

Figure 1. Calibration of the quad visible range + quad LWIR camera.

We’ve got the first results of the photogrammetric calibration of the composite (visible+LWIR) Talon camera described int the previous post and tested the new pattern. In the first experiments with the new software code we’ve got average reprojection error for LWIR of 0.067 pix, while the visible quad camera subsystem was calibrated down to 0.036 pix. In the process of calibration we acquired 3 sequences of 8-frame (4 visible + 4 LWIR) image sets, 60 sets from each of the 3 camera positions: 7.4m from the target on the target center line, and 2 side views from 4.5m from the target and 2.2 m right and left from the center line. From each position camera axis was scanned in the range of ±40° horizontally and ±25° vertically.

3D Perception with Thermal Cameras

Figure 1. Oleg carrying combined LWIR and visible range camera.

While working on extremely long range 3D visible range cameras we realized that the passive nature of such 3D reconstruction that does not involve flashing lasers or LEDs like LIDARs and Time-of-Flight (ToF) cameras can be especially useful for thermal (a.k.a LWIR – long wave infrared) vision applications. SBIR contract granted at the AF Pitch Day provided initial funding for our research in this area and made it possible.

We are now in the middle of the project and there is a lot of the development ahead, but we have already tested all the hardware and modified our earlier code to capture and detect calibration pattern in the acquired images.