Fig. 1. Schematic diagram of spatial coordinates of spectroradiometer and whiteboard

Fig. 2. Correction factors of different angles of field of view

Fig. 3. Schematic diagram of tungsten halogen lamp whiteboard system

Fig. 4. Measurement results at different angles

Fig. 5. Measurement results at different distances

Fig. 6. Correction factors of different angle errors

Fig. 7. Correction factors of different displacement errors