Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement

Area of Science:

• Optics and Photonics
• Image Processing
• Robotics and Control Systems

Background:

• Accurate positioning of space cooperative targets is crucial for visual measurement systems.
• Existing methods face precision limitations due to various influencing factors.
• Ground simulation experiments with laser spots are used to study these limitations.

Purpose of the Study:

• To investigate the influence of laser diode supply current and CCD camera exposure time on measurement precision.
• To develop a novel optimization method for improving the accuracy of cooperative target positioning.
• To overcome precision insufficiencies in current visual measurement techniques.

Main Methods:

• Established state equations describing laser spot position variation in image coordinates.
• Proposed a novel optimization method using state variables and controllable variables (diode current, exposure time).
• Calculated optimal controllable variables by intersecting focal spot centroid line and a 3-D surface, avoiding complex nonlinear equation solving.

Main Results:

• The novel optimizing method effectively determines optimal laser diode supply current and CCD exposure time.
• Experimental validation showed the method guarantees focal spot variation within 5-10 pixels.
• Achieved positioning accuracy of 0.6-1.2 mm at a simulated 3 m distance.

Conclusions:

• The proposed method significantly enhances the positioning precision of space cooperative targets.
• Optimizing laser diode current and CCD exposure time is key to improving visual measurement accuracy.
• The new algorithm offers a practical and efficient solution for high-precision target localization.