2.1 Introduction
2.1.1 Historical Context
2.1.2 Modern Systems and Applications
2.1.3 Calibration and Accuracy
2.2 Calibration Approaches
2.2.1 Physical Correction
2.2.2 Target Field Calibration
2.3 Calibration Algorithms
2.3.1 Calibration Parameters
2.3.2 Absorption of Refraction Effects
Camera | GoPro Hero4 #1 | GoPro Hero4 #2 | ||||
---|---|---|---|---|---|---|
Parameter | In-air | In-water | Ratio | In-air | In-water | Ratio |
PPx (mm) | 0.080 | 0.071 | 0.88 | −0.032 | −0.059 | 1.82 |
PPy (mm) | −0.066 | −0.085 | 1.27 | −0.143 | −0.171 | 1.20 |
PD (mm) | 3.676 | 4.922 | 1.34 | 3.658 | 4.898 | 1.34 |
Affinity | −6.74E-03 | −6.71E-03 | 1.00 | −6.74E-03 | −6.84E-03 | 1.01 |
2.3.3 Geometric Correction of Refraction Effects
2.3.4 Relative Orientation
2.4 Calibration Reliability and Stability
2.4.1 Reliability Factors
2.4.2 Stability Factors
2.5 Calibration and Validation Results
2.5.1 Quality Indicators
Technique | RMS image error (pixels) | RMS XYZ error (mm) | Proportional error |
---|---|---|---|
Absorption (Harvey and Shortis 1996) | 0.1–0.3 | 0.1–0.5 | 1:3000–1:15000 |
Absorption (Schewe et al. 1996) | 0.3 | 40–200 | 1:500 |
Geometric correction (Li et al. 1997) | 1.0 | 10 | 1:210 |
Perspective shift (Telem and Filin 2010) | 0.3 | 2.0 | 1:1000 |
Absorption (Menna et al. 2015) | 0.2–0.25 | 1.9 | 1:32000 |
2.5.2 Validation Techniques
2.5.3 Validation Results
Technique | Validation | Percentage error (%) |
---|---|---|
Absorption (Harvey and Shortis 1996) | Length measurement of silhouettes or rods throughout the volume | 0.2–0.7 |
Lens distortion grid (Petrell et al. 1997) | Calliper measurements of Chinook Salmon | 1.5 |
Absorption (Harvey et al. 2003) | Calliper measurements of Southern Bluefin Tuna | 0.2 |
Perspective shift (Telem and Filin 2010) | Flat reference plate and straight-line reconstruction | 0.4 |
Absorption (Menna et al. 2015) | Similarity transformation between above and below water networks | 0.3 |
Radial lens distortion correction (Wehkamp and Fischer 2014) | Distances on checkerboard | 0.9–1.5 |
Absorption (Boutros et al. 2015) | Length measurements of a rod throughout the volume | 0.5 |
Perspective shift (Bräuer-Burchardt et al. 2015) | Flat reference plate and distance between spheres | 0.4–0.7 |