Calibration of Microphone Arrays and Cameras
To exploit the complementary information in both video and audio image streams we must know the relative orientation of each sensor. The parameters of the orientation can be calculated if sufficient correspondence points are known in each image. To get these correspondence points we designed a calibration wand that is composed of an LED and a micro loudspeaker (figure 1).
Figure 1) Calibration Wand. A small LED and micro loud speaker are placed at the tip of the wand
Each time the LED is illuminated a broadband burst of sound is emitted from the loudspeaker and recorded at the spherical microphone array. The following movies show an example of the calibration procedure.
Figure2) Example of the calibration procedure. The left panel shows the video images of the correspondence points, The right frame shows the corresponding acoustic images.