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

Systems and method for optically imaging objects and in particular optical patterns or codes onto a detection device by a pinhole aperture are described. According to an embodiment of the invention these systems have optical attenuation elements between the illumination devices and the object which substantially compensate the system-inherent imaging detects 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 an embodiment of 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 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.