Patent ID: 9014460
Filing Date: 2015-04-21
Classification: F01D,G01H,G01M,G06T

Abstract:
1. In a gas turbine engine, an apparatus comprising: an illumination source to generate a sequence of illumination bursts in a field of view capturing a passing rotating blade of the gas turbine engine, wherein said rotating blade is mounted on a rotating shaft; an imager comprising a digital camera to generate image data comprising a series of images capturing views of the passing rotating blade in the field of view, the series of images exposed in response to respective illumination bursts, further comprising a plurality of further imagers comprising further digital cameras positioned at circumferentially spaced apart locations around the engine to generate image data comprising respective series of images acquired at the circumferentially spaced apart locations and capturing respective views of the rotating blade, the further digital cameras responsive to respective sequences of illumination bursts from further illumination sources to expose the respective series of images of the rotating blade, wherein the respective series of images of the rotating blade are spatially correlated to one another based on an expected time-of-arrival of the leading edge of the rotating blade into respective fields of view of the digital cameras; a monitor configured to generate an illumination spot directed to said passing blade, wherein the respective series of images comprise visual indicia formed at respective edges of the images in response to the illumination spot directed to said passing blade, wherein the monitor is further configured to determine the expected time-of-arrival of the leading edge of said rotating blade into respective fields of view of the digital cameras based on the visual indicia formed at the respective edges of the images, wherein the expected time-of-arrival of the leading edge of said rotating blade is based on an average of respective times of detection of said visual indicia over a plurality of revolutions of the rotating shaft, wherein the respective series of images of said passing blade are spatially correlated with one another based on the expected time-of-arrival; and a controller to process the series of images to identify at least one vibration mode of the rotating blade.