Tundish Cover Flux Thickness Measurement Method and Instrumentation Based on Computer Vision in Continuous Casting Tundish

Table 1

Horizontal and vertical angles of view of several kinds lens, which have different sizes and focuses.

Focus (mm)	Horizontal angle of view for 1/3 inch	Vertical angle of view for 1/3 inch	Horizontal angle of view for 1/4 inch	Vertical angle of view for 1/4 inch
2.5 mm	96.4°	86.2°	81.9°	72.9°
2.8 mm	89.9°	79.8°	75.6°	66.8°
3.6 mm	75.7°	66°	62.2°	54.3°
4 mm	69.9°	60.7°	57°	49.5°
6 mm	50°	42.6°	39.8°	34.2°
8 mm	38.5°	32.6°	30.4°	26°
12 mm	26.2°	22.1°	20.5°	17.5°
16 mm	19.8°	16.6°	15.4°	13.2°
30 mm	10.6°	8.9°	8.3°	7°
60 mm	5.3°	4.5°	4.1°	3.5°
100 mm	3.2°	2.7°	2.5°	2.1°
200 mm	1.6°	1.3°	1.2°	1.1°