In autostereoscopic display using LASER beam scanning type of multiple projectors, accurate projector calibration is essential to alleviate optical distortions such as keystone distortion. However, calibrating hundreds of projectors with high accuracy takes too much time and effort. Moreover, there exist a limited range where viewers can percept correct depth with respect to human visual system (HVS) although the ideal projector calibration is possible. After fine projector calibration, we explored its accuracy with a brute-force technique, and analyzed depth expression ranges (DER) in the given accuracy with respect to HVS. We set five error conditions for projector calibration accuracy. And then we derive correlation between projector calibration error (PCE) and DER, and determine accuracy of projector calibration affect DER. And we determine that there is no problem in that the observer can perceive the depth of 3D object up to a certain accuracy of projector calibration. From this result, we proposed a perceptive threshold for acceptable projector calibration accuracy for whole system's efficiency eventually.