Cognex Corporation

Brown University

Daniel Moreno

Gabriel Taubin

Hongwei Zhu

David J Michael

Nitin M Vaidya

Ben R Carey

Nickolas James Mullan

Gilbert Chiang

Yukang Liu

Fatih Calakli

The techniques described herein relate to methods, apparatus, and computer readable media configured to determine an estimated volume of an object captured by a three-dimensional (3D) point cloud. A 3D point cloud comprising a plurality of 3D points and a reference plane in spatial relation to the 3D point cloud is received. A 2D grid of bins is configured along the reference plane, wherein each bin of the 2D grid comprises a length and width that extends along the reference plane. For each bin of the 2D grid, a number of 3D points in the bin and a height of the bin from the reference plane is determined. An estimated volume of an object captured by the 3D point cloud based on the calculated number of 3D points in each bin and the height of each bin.

Methods and apparatus for determining volumes of 3D images

This invention provides a system and method that efficiently detects objects imaged using a 3D camera arrangement by referencing a cylindrical or spherical surface represented by a point cloud, and measures variant features of an extracted object including volume, height, and center of mass, bounding box, and other relevant metrics. The system and method, advantageously, operates directly on unorganized and un-ordered points, requiring neither a mesh/surface reconstruction nor voxel grid representation of object surfaces in a point cloud. Based upon a cylinder/sphere reference model, an acquired 3D point cloud is flattened. Object (blob) detection is carried out in the flattened 3D space, and objects are converted back to the 3D space to compute the features, which can include regions that differ from the regular shape of the cylinder/sphere. Downstream utilization devices and/or processes, such as part reject mechanism and/or robot manipulators can act on the identified feature data.

System and method for extracting and measuring shapes of objects having curved surfaces with a vision system

A system and method for estimating dimensions of an approximately cuboidal object from a 3D image of the object acquired by an image sensor of the vision system processor is provided. An identification module, associated with the vision system processor, automatically identifies a 3D region in the 3D image that contains the cuboidal object. A selection module, associated with the vision system processor, automatically selects 3D image data from the 3D image that corresponds to approximate faces or boundaries of the cuboidal object. An analysis module statistically analyzes, and generates statistics for, the selected 3D image data that correspond to approximate cuboidal object faces or boundaries. A refinement module chooses statistics that correspond to improved cuboidal dimensions from among cuboidal object length, width and height. The improved cuboidal dimensions are provided as dimensions for the object. A user interface displays a plurality of interface screens for setup and runtime operation.

System and method for refining dimensions of a generally cuboidal 3D object imaged by 3D vision system and controls for the same

A system and method to capture the surface geometry a three-dimensional object in a scene using unsynchronized structured lighting is disclosed. The method and system includes a pattern projector configured and arranged to project a sequence of image patterns onto the scene at a pattern frame rate, a camera configured and arranged to capture a sequence of unsynchronized image patterns of the scene at an image capture rate, and a processor configured and arranged to synthesize a sequence of synchronized image frames from the unsynchronized image patterns of the scene. Each of the synchronized image frames corresponds to one image pattern of the sequence of image patterns.

Method and system for unsynchronized structured lighting

Techniques for scanning through structured light techniques that are robust to global illumination effects and that provide an accurate determination of position as provided. According to some aspects, described techniques may be computationally efficient compared with conventional techniques by making use of a novel approach of selecting frequencies of patterns for projection onto a target that mathematically enable efficient calculations. In particular, the selected frequencies may be chosen so that there is a known relationship between the frequencies. This relationship may be derived from Chebyshev polynomials and also relates the chosen frequencies to a low frequency pattern.

Techniques for shape measurement using high frequency patterns and related systems and methods

A method obtains the shape of a target by projecting and recording images of dual frequency fringe patterns. Locations in each projector image plane are encoded into the patterns and projected onto die target while images are recorded. The resulting images show the patterns superimposed onto the target. The images are decoded to recover relative phase values for the patterns primary and dual frequencies. The relative phases are unwrapped into absolute phases and converted back to projector image plane locations. The relation between camera pixels and decoded projector locations is saved as a correspondence image representing the measured shape of the target. Correspondence images with a geometric triangulation method create a 3D model of the target. Dual frequency hinge patterns have a low frequency embedded into a high frequency sinusoidal, both frequencies are recovered in closed form by the decoding method, thus, enabling direct phase unwrapping.

System and methods for shape measurement using dual frequency fringe pattern

A method that estimates the coordinates of the calibration points in the projector image plane using local homographies obtained from the imaging camera. First, a dense set of correspondences between projector and camera pixels is found by projecting onto the calibration object an identical pattern sequence as the one later projected when scanning the target, reusing most of the software components written for the scanning application. Second, the set of correspondences is used to compute a group of local homographies that allow projection back of any of the points in the calibration object onto the projector image plane with sub-pixel precision. In the end, the data projector is then calibrated as a normal camera.

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Northbridge, MA, United States of America

Daniel Moreno