SYSTEM AND METHOD FOR OPTICALLY IMAGING OBJECTS ON A DETECTION DEVICE BY MEANS OF A PINHOLE APERTURE

摘要

The invention describes systems and methods for optically imaging objects and in particular optical patterns or codes onto a detection device by means of a pinhole aperture. According to the invention these systems have optical attenuation elements between the illumination devices and the object which substantially compensate the system-inherent imaging defects caused by the pinhole aperture and in particular the system-inherent peripheral decrease in brightness of an image of the object formed by a pinhole aperture on the detection device. According to the invention the optical attenuation elements change the illumination intensity of the object in such a manner that the central areas of the object are illuminated at a lower light intensity than its peripheral areas. As a result of the subsequent imaging of the object by means of a pinhole aperture, the central areas of the object are imaged onto the detection device at a higher light intensity than the peripheral areas of the object. The superimposition of the two effects enables the imaging system according to the invention to achieve a substantially uniform system-inherent brightness distribution on the detection device.