In one general aspect, a system for aseptically filling a tray of pharmaceutical containers with a pharmaceutical product is disclosed, which consists of an aseptic chamber, one or more articulated arms within the chamber, a sensor aseptically disposed with respect to the chamber, and a controller. The controller determines the locations of openings of the containers based on the image information from the sensor, and automatically guides one of the arms to fill the containers with the product. In order to obtain suitable contrast for accurately identifying the openings, an illuminator illuminates the tray with substantially collimated light. The sensor images the tray and containers using collimated light reflected from a reflective surface such as a retroreflector under the tray. To this end, the sensor may be disposed at a large enough distance from the retroreflector to collect largely the retroreflected light, or the sensor may employ a telecentric lens or a Fresnel lens. Further articulated arms move the tray and stopper the containers.
