Cognex Corporation

Ruibing Wang

David J Michael

Aaron S Wallack

Hongwei Zhu

Robert A Wolff

Gang Liu

Ali Moghaddam Zadeh

Matthew R Reome

Benjamin D Klass

This invention provides an easy-to-manufacture, easy-to-analyze calibration object which combines measurable and repeatable, but not necessarily accurate, 3D features&#x2014;such as a two-sided calibration object/target in (e.g.) the form of a frustum, with a pair of accurate and measurable features, more particularly parallel faces separated by a precise specified thickness, so as to provide for simple field calibration of opposite-facing DS sensors. Illustratively, a composite calibration object can be constructed, which includes the two-sided frustum that has been sandblasted and anodized (to provide measurable, repeatable features), with a flange whose above/below parallel surfaces have been ground to a precise specified thickness. The 3D corner positions of the two-sided frustum are used to calibrate the two sensors in X and Y, but cannot establish absolute Z without accurate information about the thickness of the two-sided frustum; the flange provides the absolute Z information.

System and method for calibrating a plurality of 3D sensors with respect to a motion conveyance

This invention provides a system and method for concurrently (i.e. non-serially) calibrating a plurality of 3D sensors to provide therefrom a single FOV in a vision system that allows for straightforward setup using a series of relatively straightforward steps that are supported by an intuitive graphical user interface (GUI). The system and method requires minimal data input about the scene or calibration object used to calibrate the sensors. 3D features of a stable object, typically employing one or more subobjects, are first measured by one of the image sensors, and then the feature measurements are used in a calibration in which each of the 3D sensors images a discrete one of the subobjects, resolves features thereon and computes a common coordinate space between the plurality of 3D sensors. Sensor(s) can be mounted on the arm of an encoderless robot or other conveyance and motion speed can be measured in setup.

System and method for calibrating one or more 3D sensors mounted on a moving manipulator

This invention provides a system and method for concurrently (i.e. non-serially) calibrating a plurality of 3D sensors to provide therefrom a single FOV in a vision system that allows for straightforward setup using a series of relatively straightforward steps that are supported by an intuitive graphical user interface (GUI). The system and method requires minimal input significant data about the imaged scene or calibration object used to calibrate the sensors, thereby effecting a substantially 'automatic' calibration procedure. 3D features of a stable object, typically employing a plurality of 3D subobjects are first measured by one of the plurality of image sensors, and then the feature measurements are used in a calibration in which each of the 3D sensors images a discrete one of the subobjects, resolves features thereon and computes a common coordinate space between the plurality of 3D sensors. Laser displacement sensors and a conveyor/motion stage can be employed.

This invention provides a system and method for reading and decoding ID features located on a surface of a curved, sloped and/or annular object, such as a tire moving on a conveyor. A plurality of 3D sensors are operatively connected to a vision system processor. The sensors are calibrated by calibration parameters to generate a stitched-together 3D image of a field of view in a common coordinate space. A motion conveyance (e.g. a conveyor) causes the object and the 3D sensors to move in relative motion, and the conveyance provides motion information to the vision system processor. An ID finder locates ID features within a version of the 3D image and a decoder (e.g. an OCR reader) generates data from the ID features. The ID finder can locate a trained portion of the ID and the search for variable code elements at a known orientation relative to the trained portion.

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Framingham, MA, United States of America

Ruibing Wang