Systems and methods for controlling strobe illumination

摘要

The repeatability of strobe illumination for image exposure is improved over a wide dynamic range in a machine vision system wherein a relationship between a camera integration period and a pulse duration of a strobe light generator control the effective exposure of a camera image during a timing overlap between a beginning of the camera integration period and an end of the pulse duration. To avoid noise in the illumination, the illumination pulse duration may start, the camera integration period may begin after a delay relative to that start and not later than the end of the pulse duration, the pulse duration may end, and the camera integration period may end not earlier than the end of the pulse duration. The timing overlap may also be synchronized with a periodic ripple component in the strobe illumination, to provide improved repeatability.

主权项

1. A machine vision system that controls image exposure strobe illumination used to illuminate a workpiece, such that the workpiece may be imaged by a camera in the machine vision system while moving at high speed, the system comprising:
a camera providing a camera image of the workpiece; a strobe light generator that emits radiation used by the camera for imaging; and a controller configured to control a timing relationship between an image integration period of the camera and a pulse duration of the radiation emitted by the strobe light generator to control an image exposure of a camera image during a timing overlap which occurs between a beginning of the image integration period and an end of the pulse duration, wherein the timing relationship is controlled such that the pulse duration starts, the image integration begins after a delay relative to a start of the pulse duration and not later than the end of the pulse duration, the pulse duration ends, and the image integration period ends not earlier that the end of the pulse duration.