IMAGE PICKUP DEVICE FOR MONITORING VEHICLE NUMBER

摘要

PROBLEM TO BE SOLVED: To prevent an illumination image from being projected on an image pickup object. SOLUTION: Illumination light generated from an illumination device 4 passes through an illumination side polarizing plate 1 and is linearly polarized in the direction of an angleθto a horizontal line when viewed from an illumination device side. The linearly polarized illumination light is reflected on a number plate 7. Mirror reflection components of reflected light are interrupted by an image pickup side polarizing plate 2 and diffused reflection components pass through the image pickup side polarizing plate 2. The mirror reflection components of a wavelength for which the image pickup side polarizing plate 2 does not have interruption ability are interrupted by an optical filter 3. Only diffused components are made incident on a CCD camera 5. COPYRIGHT: (C)2004,JPO