Eastman-kodak Company

H Galen Parker

Richard Dean Young

Russell J Palum

Martin C Kaplan

Douglas S Finnicum

Robert B Bilhorn

An image processor based system and method for recognizing predefined-types of coating density imperfections in a web, specifically continuous type or streak imperfections. Continuous type imperfections are recognized in a continuous web moved at a certain rate through an imaging region illuminated by a stripe of substantially constant illumination. A time-delay integrating CCD camera is focused on the illuminated imaging region. The TDI CCD camera comprises an array of N rows of M light sensitive CCD elements each imaged on a fixed discrete pixel-related image area of the illuminated imaging region. The charge levels accumulated in the CCD elements of each row are shifted to the succeeding row or CCD elements and summed with the charge levels therein at a line shift clock frequency that ensures that an asynchronous relationship exists with respect to the incremental movement of the web. During the clock cycle of the N rows, the corresponding pixel areas of the illuminated web shift asynchronously or creep through the discrete pixel-related image areas. The accumulated pixel charge values derived from the pixel-related image areas of the illuminated region of said moving web emphasize imaging of longitudinal streak imperfections in the web due to the asynchronous movement the web.

Coating density analyzer and method using non-synchronous TDI camera

A highly uniform infrared illumination source for illuminating a stripe of a moving sensitized web for line scan imaging of imperfections in the coating on the web by a CCD imaging camera. A light integrator having an elongated housing formed with side and end walls defines a linear light integrating cavity having diffusely reflecting interior wall surfaces. An elongated array of infrared LEDs is spaced along the side wall for emitting light into the cavity for integration within the cavity. A longitudinally extending slit is formed in the side wall through which a diffuse, linear light beam exits the elongated slit having a varying longitudinal intensity profile. The intensity of the light emitted by the LEDs is modulated in an intensity pattern that alters the varying longitudinal intensity profile of the linear light beam to provide a desired longitudinal intensity profile of the stripe of diffuse illumination. Preferably, the intensity modulation renders more uniform the longitudinal intensity profile of the linear light beam illuminating the web as viewed by the imaging camera. The desired light intensity profile along the length of the emitted light beam is achieved by clustering the LEDs with LED drive circuits operated at different drive currents as a function of a set point control signal appropriate to the characteristics of the imaging camera and a transmitted light intensity feedback signal to maintain the intensity pattern of the LEDs and the uniform intensity profile as viewed by the imaging camera regardless of the optical density of the web.

Linear integrating cavity light source for infra-red illumination of

An image processor based system and method are provided for recognizing predefined-types of coating density imperfections in a web. Specific imperfection-types to be analyzed include continuous-type, as well as point-type, anomalies. Continuous-type imperfections are recognized in a moving continuous web through the accumulation and integration of density data on the web passing through a system imaging area. Depending upon the type of imperfection to be imaged, the light source provides either constant illumination or strobed illumination of the moving coated web. For most types of imperfections, transmissive illumination of the web is used, however, for point-type anomalies reflective illumination is possible, particularly if the web is static. A machine vision image processor contains predefined lookup tables which allow adaptive control of web illumination within the imaging area. An integrating sphere is used to provide for uniform web illumination. Corresponding machine vision based imperfection recognition processing routines are also described.

Growing community of inventors

Rochester, NY, United States of America

H Galen Parker