Photogrammetric Kinematics // Protocol OVL-03
Photogrammetry Overlap & Shutter Interval Calculator
Calculate forward overlap (75%–85%), lateral side overlap (65%–75%), minimum shutter trigger cycle time, flight line pitch, and pixel motion blur thresholds.
80 meters
80%
Rec: 75% - 85% for 3D terrain
70%
Rec: 65% - 75% for tie-point density
10 m/s (36 km/h)
Shutter Kinematics Output
Required Shutter Trigger Interval
1.70seconds
Drone must trigger every 17.0 meters along track
Flight Line Spacing
34.0 m
Across-track strip pitch
Max Safe Flight Speed
24.4 m/s
(88 km/h limit)
Motion Blur During Exposure:0.29 pixels (Crisp Sub-Pixel)
Single Frame GSD:2.15 cm/px
Ground Footprint:113m wide × 85m high
Structure from Motion (SfM) Protocols
The Geometrical Imperative of Image Overlap
1. Multi-Ray Triangulation & Epipolar Geometry
In photogrammetry algorithms (Agisoft Metashape, Pix4D, RealityCapture), a 3D tie point requires observation from at least 3 distinct photos. With 80% forward and 70% side overlap:
Advance = H_ground · (1 - Overlap_front) | Pitch = W_ground · (1 - Overlap_side)
Every physical surface feature is captured in 6 to 9 consecutive frames. This redundant bundle adjustment eliminates camera intrinsic distortion and resolves dense point clouds without surface holes.
2. Pixel Motion Blur Criterion
While the camera shutter is open (t_shutter seconds), the drone moves a physical distance d = v · t_shutter.
- Rule of Thumb: Total physical motion during exposure should remain strictly below 0.5 GSD (half a pixel).
- Consequence: If blur exceeds 1.0 pixel, SIFT keypoint gradient vectors become smeared, causing automated point matching to reject tie-points and misestimate surface elevation.