Single-camera angled conveyance imaging method and apparatus for whole-surface inspection of rotating objects
Inventors
Kim, Moon S. • Chao, Kuanglin • Lefcourt, Alan M. • Lee, Kangjin • Kang, Sukwon • Chan, Diane E.
Assignees
Korea Rural Development Administration • US Department of Agriculture USDA
Publication Number
US-9568438-B1
Publication Date
2017-02-14
Expiration Date
2033-03-01
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Abstract
The single-camera angled conveyance inspection method and apparatus includes upwardly and downwardly angled conveyance mechanisms positioned within an instantaneous field of view of a digital line scan camera. As a rotating object is moved over the conveyances by a helical guide, the camera obtains images of the object and communicates the images to a processor. The processor assembles a reflectance and fluorescence image of the object including detected defects and/or contamination on the outer surface of the object.
Core Innovation
The invention disclosed relates to a method and apparatus for imaging the entire surface of a rotating, preferably spheroidal, object such as fruits and vegetables. This is achieved by using an angled conveyance system comprising downwardly and upwardly angled conveyances with rotating members and helical guides, which rotate and move the object through the instantaneous field of view (IFOV) of a single digital line scan camera. The camera captures images, which a processor assembles into a reflectance and fluorescence image, enabling detection of surface defects and contamination on the object's outer surface.
The problem addressed by this invention arises from the limitations of current inspection methods, which often rely on human visual inspection that is slow, unreliable, and unable to systematically view all surfaces of inspected spheroidal objects. Existing machine vision systems use multiple cameras to capture images of all surfaces but are expensive and complex, requiring synchronization and rapid data processing to prevent mixing defective with non-defective items. The present invention simplifies this process by utilizing only one camera and processor to efficiently gather whole-surface imaging data for defect and contamination detection.
The apparatus includes downwardly and upwardly angled conveyance mechanisms forming essentially a 'V' shape, with rotating elongated members encircled by helical guides that direct and rotate objects as they move through the system. Positioned so the camera’s IFOV encompasses both conveyances, this arrangement increases exposure of surfaces that would be otherwise hidden with traditional horizontal conveyors. The processor compiles images into a three-dimensional 'image cube' depicting the entire object surface and applies predetermined defect and contamination thresholds to decide whether to retain or reject the object. The system is adaptable for reversed conveyance positions and may be extended for non-spheroidal objects or non-food items with modifications.
Claims Coverage
The claims present two independent claims covering an inspection system and a method for inspecting rotating objects using a combined angled conveyance and imaging approach.
Inspection system with single-camera angled conveyance imaging
An inspection system comprising downwardly and upwardly angled conveyances, each with rotating members and encircling helical guides that rotate the object in the same first direction as it moves downward and upward respectively. A camera obtains images within an instantaneous field of view that includes both conveyances, and a processor receives these images to produce object image data, based on which the object is retained or rejected.
Method for inspecting rotating objects via angled conveyance and single camera
A method involving conveying an object down a downwardly angled conveyance and then up an upwardly angled conveyance, both comprising parallel cylinders with helical guides that rotate and move the object. A digital line scan camera positioned such that its IFOV includes parts of both conveyances gathers image data, which is processed to form an image cube that depicts the object's outer surface through at least one full rotation, enabling defect and contamination detection for retention or rejection decisions.
The independent claims cover a novel system and method that utilize a single digital line scan camera and angled conveyance mechanisms with rotating members and helical guides to inspect the entire surface of rotating objects, producing comprehensive image data used for defect and contamination assessment to decide on retaining or rejecting the object.
Stated Advantages
Simplifies the imaging process by requiring only one camera and processor instead of multiple cameras.
Provides thorough inspection by increasing exposure of the object's surface that would otherwise be hidden in traditional horizontal inspection systems.
Enables rapid and effective detection of surface defects and selected bacterial contamination such as fecal matter on rotating spheroidal objects.
Documented Applications
Inspection of spheroidal food products such as fruits and vegetables on a conveyor line for quality and contamination.
Potential application to inspection of non-spheroidal food or non-food items, including manufactured products, with modifications.
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