Simple harmonic error cancellation in time of flight range imaging.

Area of Science:

• Optics and Photonics
• Metrology
• Signal Processing

Background:

• Amplitude Modulated Continuous Wave (AMCW) Time of Flight (ToF) range imaging offers full-field distance measurements.
• Digital hardware in AMCW ToF systems introduces harmonic content, a primary source of measurement error.
• Current harmonic correction methods often require extra measurements and can amplify noise.

Purpose of the Study:

• To develop an improved data acquisition procedure for AMCW ToF range imaging.
• To intrinsically correct for harmonic errors without auxiliary measurements.
• To specifically target and eliminate the third harmonic, a significant contributor to distance measurement inaccuracies.

Main Methods:

• A minor modification to the standard data acquisition procedure for AMCW ToF systems was implemented.
• The modified procedure was designed to be inherently invariant to specific harmonic frequencies.
• Focus was placed on eliminating the third harmonic, a dominant source of error.

Main Results:

• The modified acquisition procedure successfully eliminated the third harmonic component.
• The elimination of the third harmonic was achieved without a significant increase in the noise variance.
• Distance measurements are intrinsically more accurate due to harmonic reduction.

Conclusions:

• A novel, simple modification to AMCW ToF data acquisition effectively suppresses harmonic errors.
• This method provides intrinsic harmonic invariance, reducing the need for complex post-processing.
• The technique enhances the accuracy of distance measurements in ToF imaging systems without compromising noise levels.