Three-dimensional Machine Vision Using Gated Imaging System: A Numerical Analysis

Various researchers have suggested techniques in gated imaging and "smart" pixels technologies that achieve simultaneous depth mapping and optical imaging with enhanced depth detection accuracy and resolutions range from a few cm to less than 1 mm. In this paper, we demonstrate how depth accuracy and resolution can be studied more systematically (and depending on the range detection technique). We propose that the depth detection and resolution study should be treated as two separate configurations. In particular, we recommend statistical approach for camera gating shorter than (or equal to) target irradiance and quantitative approach for gating time longer than target irradiance. A very accurate method by J. Busck is analyzed as an example of the statistical approach. The results indicate that the depth accuracy is less affected by the reflected Gaussian noise for longer range targets. The numerical analysis shows that it is necessary to introduce a correction based on the gating and target irradiance profiles to achieve accurate depth detection. An objective quantitative evaluation method is also discussed. It is suggested to replace the existing subjective measure in determining the depth resolution by the proposed approach. Supporting data for this approach will be presented in future works