Fig. 1. Detecting divided aperture laser differential confocal radius measuring principle

Fig. 2. Principle for off-axis differential detection using D-type aperture

Fig. 3. Virtual pinhole location algorithm

Fig. 4. Fixed focus sensitivity changes with v_M

Fig. 5. Variation of fixed focus sensitivity with pinhole's radius

Fig. 6. Detecting divided aperture laser differential confocal radius measurement instrument

Fig. 7. Differential confocal curves of cat's eye point and confocal points