Structured Illumination Projection With Enhanced Exposure Control

摘要

A method for controlling a structured illumination pattern generating portion is provided for illuminating a workpiece during an image acquisition by a camera in a precision machine vision inspection system. A controllable spatial light modulator (e.g., a digital light processing projector) is part of the generating portion for generating the structured illumination pattern. The pattern may comprise an array of stripes including a sinusoidal gray level intensity variation across each stripe. An overall image exposure is increased by repeating a complete structured illumination pattern generation iteration, including gray level variation, a plurality of times during an image integration period. Structured illumination microscopy techniques for determining a workpiece surface profile may benefit, wherein multiple (e.g., 3 or 4) images are acquired at respective focus positions to be analyzed, by using the method to project a different phase of a structured light pattern for each of the multiple images.

主权项

1. A method for controlling a structured illumination pattern generating portion used to illuminate a workpiece with a structured illumination pattern during an image acquisition by a camera portion in a precision machine vision inspection system, wherein:
the structured illumination pattern (SIP) generating portion comprises:
a SIP controller;a controllable spatial light modulator (SLM) that is controlled for generating the structured illumination pattern; anda light generator that emits radiation to the SLM; and the method comprises:
acquiring an image during an image integration period of the camera;increasing the overall exposure during the image integration period by a first exposure increment by generating a first complete structured illumination pattern iteration including gray level variations; andincreasing the overall exposure during the image integration period by at least a second exposure increment by generating at least a second complete structured illumination pattern iteration including gray level variations.