Variable frame time imaging for indirect time of flight range imaging cameras

This paper outlines a method for improving the precision of indirect time of flight range imaging cameras in high contrast scenes. Indirect time of flight cameras have potential applications in many fields including mobile robotics. However, current generation cameras are limited by their dynamic range. A method is proposed where, at the end of each measurement, the signal amplitude is compared to a threshold value on a pixel-by-pixel basis with low quality pixels being integrated over multiple integration periods. This method sacrifices the uniformity of the frame rate over the image in return for maintaining a high frame rate in bright areas while still measuring quality data in darker areas. Experimental data are shown demonstrating the efficacy of this method.