Time-Of-Flight 3D Range Camera Based on Code Modulating Technique

Abstract

We developed a new signal processing technique for a 3D real-time imager that is based on the time-of-fight method. The use of a code-signal modulation technique enables us to solve some of the problems with the distance measurements. One problem is the ambiguous measurement caused by the cyclic repetition of the signal phase according to the propagation distance when using the conventional CW modulation technique. The second problem is caused by the mixture of signals reflected on the glass panel and at the object through the glass. The code-signal modulation technique with the noise filter excludes the ambiguous signals reflected from the background objects at long distances over the modulation period. In addition, the signal correction process extracts the intended signal reflected at the object through the glass. With this novel signal-processing the utility of the 3D real-time imager can be further extended.