Patent Publication Number: US-2021166059-A1

Title: Debris detection system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/928,704 filed on Mar. 22, 2018, now U.S. Pat. No. 10,902,281, the entire disclosure of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The invention generally relates to imaging objects on a conveyor transport system, and identifying foreign items to signal an alarm in order to have the foreign items removed. More particularly, the invention relates to a debris detection system and method used with existing conveyors in egg production systems having a flat, continuous process and adapted to be placed over the existing conveyors without interruption of the flow process. 
     2. Description of the Related Art 
     The largest poultry farms in the U.S. produce 750 billion eggs per year. To produce, grade, wash, and package that amount of eggs requires a significant amount of investment in the machinery. Egg production stoppage due to machine breakdown is a key concern and significant monetary loss to the poultry farm owner-operator. Obvious issues are employee down time, backlog of egg processing and packaging, and delivery truck backup at loading docks. The other concern is the time and money required to find and transport an experienced technician, including the shipment of parts, out to a farm in a remote area of the country. The breakdown of egg processing machinery might cause the farm to be down for multiple days which will result in significant losses. If the farm is unable to process the chicken eggs in a timely manner, large quantities of eggs accumulate in the chicken houses and on the conveyor belts, which ultimately cause eggs to be damaged preventing them from being sold for human consumption. 
     One major cause of egg processing equipment breakdown is foreign objects and/or debris on an egg conveyor leading into an egg grading machine. Current means of keeping foreign debris from disrupting egg production requires human visual detection coupled with the requisite removal action. With transport systems moving eggs through the line at a speed of 0.01 mph up to 35 mph, this becomes difficult and prone to compromise. 
     There are egg quality detection systems in the prior art, such as U.S. Pat. No. 5,277,320 in the name of Corkill et al., U.S. Pat. No. 6,433,293 in the name of Bollinger et al. and U.S. Pat. No. 7,474,392 in the name of Van Soest. However, these systems merely look at the quality of the egg and types. 
     There are also sorting systems for detecting debris in a falling flow of food items, such as in U.S. Pat. No. 9,000,319 in the name of Deefholts, United States Patent Application Publication No. 2015/0224544 in the name of McGloughlin et al. and Unites States Patent Application Publication No. 2015/0283586 in the name of Dante et al. These systems are integrally inserted within a system and sort during falling of the food items. 
     SUMMARY OF THE INVENTION 
     The conveyor debris detection system and method detects objects including foreign objects and preset objects moving along a conveyor. The conveyor debris detection system includes a frame for placement above the conveyor, a lighting unit attached to the frame for illuminating the conveyor below the frame, a camera attached to the frame for capturing images of the objects moving along the conveyor wherein the images are captured at preset time intervals. A processor unit receives the images and distinguishes the objects as either foreign objects or preset objects and the processor initiates a debris signal when foreign objects are identified. An alarm system sounds an alarm when foreign objects are detected. 
     If foreign materials are detected, the operator will be notified before the foreign material becomes lodged in the machines internal components and causes damage. As a result, breakdown of egg processing machinery is minimized, saving the poultry farmer substantial downtime and money. In addition, the unit will also prevent foreign material, such as chicken body parts and manure from going into the wash-water in the egg washing machines used to clean the eggs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of the debris detection system; 
         FIG. 2  is a perspective view of the frame of the system; 
         FIG. 3  is a perspective bottom view of the debris detection system; 
         FIG. 4  illustrates a simplified schematic of the system; and 
         FIG. 5  illustrates a flow chart of the processor of the system. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a debris detection system  10  for use with a conveyor  12  during an egg production process. The conveyor  12  transports eggs  14  in a horizontal motion moving along a flat surface. The debris detection system  10  can be used in conjunction with any type of egg conveyor  12  such as a conveyor belt, or may include any other type of horizontal moving transport system for the eggs, including rollers or spool bars, flat plastic belts available from intralox®, rod conveyors, etc. Though the invention is described as it relates to egg production, the system  10  may also be used in other industrial, agricultural production environments where foreign object detection is necessary. 
     Conveyor  12  continuously moves through different stations from production of the egg to packaging of the egg, including in between an egg grading machine, washing machine, etc., without stopping. The debris detection system  10  may be placed anywhere along the conveyor  12  to detect and signal when a foreign object  16  is found as different from a preset object  14 , namely an egg, and requires removal. Typically, the debris detection system  10  will be placed before the egg washing machine and before the egg grading machine, or it may be placed over the egg grading machine. 
     As best illustrated in  FIG. 2 , the debris detection system  10  includes a frame  20  for placement above the egg conveyor or transport system  12 . The majority of conveyors  12  used in egg production are white or off-white in color. The debris detection system  10 , and more particularly the frame  20 , may be suspended from the ceiling, bolted to other egg related machinery, bolted to the transport frame, or it may sit on a stand so that the bottom of the debris detection system  10  sits with a minimum clearance of one inch to a maximum of 75 feet above the conveyor or transport system.  FIG. 1  illustrates the debris detection system  10  suspended from the ceiling by mounting supports  22 . 
     The frame  20  includes a plurality of corner supports  24  supporting an arcuate roof  26 . A base frame member  28  is fixed to the lower ends of the corner supports  24  to support the assembly  20  and provide an open bottom for debris detection therethrough. Shelf supports  30  are established at front  32  and rear  34  ends. The shelf supports  30  provide support for electronic housings  36  thereon for containing the electronic components of the system  10 . Center side frame supports  40  provide further structural stability and support. The frame  20  includes a central mounting bar  42 , best illustrated in  FIG. 3 , positioned along an interior of the roof  26  and on the inside of the system  10  for supporting electronics as subsequently discussed. 
     The debris detection system  10  includes a housing  44  for covering the frame  20 . The housing  44  is supported by the frame  20  and includes a plurality of access doors  46 - 50  on the front, back and sides for access therein. The housing  44  protects the components secured on the frame  20  and allows a self-contained unit that can be adapted and placed over any egg conveyor  12 . Typically, the housing  44  may be formed from stainless steel sheeting or other suitable material for the egg processing environment. 
     A lighting unit  52  illuminates the conveyor  12  within a detection area. The lighting unit  52  is attached to the central mounting bar  42  and may include a dedicated LED panel and LED drivers to evenly illuminate the eggs  14  and detection area. The dedicated LED panel  52  is focused downward onto the oncoming eggs  14 . Light intensities are typically set from 100 to 10000 lumens and a color temperature of from 1000K to 10,000K depending on analysis parameters and for eliminating shadows. The lighting unit  52  may include multiple LED panels as necessary to illuminate the detection area, and two panels  52  illustrated in  FIG. 1 . Depending on the conveyor  12 , an optional lower light panel  54  may be installed underneath the conveyor  12  as a backlight for detection and include a 300×1500 mm 6000K LED light. Alternatively, a white or off-white backdrop (not shown) can be placed under the conveyor  12  when the conveyor  12  consists of rollers and not a continuous loop belt. To further eliminate false positive signals due to shadows, flat, wide light panels  55  are secured to each of the access doors  46 - 50  (one flat, wide light panel  55  shown in  FIG. 3 ). The flat, wide light panels  55  may be parallel to the access doors  46 - 50  or they may be tilted inwardly such that the light emitted by the flat, wide light panels  55  are generally directed downwardly. In one embodiment, the flat, wide light panels  55  are tilted inwardly and downwardly at 15° with respect to a bottom edge of each of the flat, wide light panels  55  that are either secured to an inner surface of an access door  46 - 50  or disposed immediately adjacent thereto. 
     A camera  60  is attached to the central mounting bar  42  of the frame  20  for capturing images of objects moving along the conveyor  12 . The images are captured at preset time intervals. Multiple cameras  60  may be used to inspect the detection area typically equal to the width of the conveyor  12 . The Figures illustrate the use of a single camera  60  centrally located along the mounting bar  42  and the fan pattern extending from the camera  60  represents the detection area. The camera  60  is typically a color camera with suitable speed and resolution to capture RAW images from 11 to 120 frames per second depending on the inspection application. The camera  60  can be set to capture images at one per second intervals without stopping the conveyor  12 . However, it is within the scope of the invention to use other sampling rates depending on conveyor speed, etc. The detection area is typically the entire cross section of the conveyor  12  located below the assembly, commonly a two-foot by six-foot (2 ft.×6 ft.) area. 
     A motion sensor  62  is directed toward the conveyor  12 , typically by means of a proximity switch, photo-eye or encoder, or other motion detecting device, to send an enable signal when the conveyor  12  starts motion to trigger the camera  60  to initiate image capture. 
     A processor unit  64  receives the images from the camera  60  and distinguishes the objects as either foreign matter  16  or acceptable matter  14 , e.g., eggs. The processor unit  64  is programmed to identify the color of the conveyor  12  and the color of the eggs  14 . The processor unit  64  is programmed to identify numerous different shades of color. The processor unit  64  is then able to filter the conveyor  12  and the eggs  14  out of any images captured by the camera  60 . And all that remains will include conveyor seams (none shown) and debris. The processor unit  64  can be programmed to ignore the conveyor seams and small specs of debris, with the remainder of the objects being identified as being debris that needs to be removed from the conveyor  12 . 
     The processor unit  64  may be integrally part of the camera  60  or separate therefrom. The processor unit  64  initiates a warning and debris signal when foreign objects  16  are identified above a predetermined magnitude. A small size or types of debris such as feathers or smaller debris may be considered acceptable matter wherein no debris signal will be initiated since smaller size debris will not cause damage to equipment. 
     The warning signal is received by an audible alarm  66  to provide audible indication of the sensed foreign object  16 . The debris signal is received by visual alarm  68  to also notify the operator to remove the debris, such visual alarm typically being a warning light that may have different wavelength outputs depending on the severity of the alarm. A reset button  70  sends a reset signal upon activation thereof by an operator and is connected to the processor unit  64  to reset the alarms  66 ,  68  when activated by the operator. If the operator does not remove the debris and push the reset button  70  within an adjustable time frame, typically 15-60 seconds, the processor unit  64  will send a shutoff signal to a shutoff switch  72  which will stop the conveyor  12 . The system  10  also includes a speed control switch  74  which is connected between the processor unit  64  and conveyor controller to slow the conveyor  12  during the time delay if the reset button  70  is not activated. 
     The processor unit  64  processes the captured images at high speed and translates the data into inspection events. The processor unit  64  uses software having computer vision and object recognition algorithms known to those skilled in the art that learn and match patterns in the pixels using appearance based or feature based techniques. Images are processed in milliseconds, and inspection events are created locally in real-time. This is because the processor unit  64  filters out all data that shares the color of the conveyor  12  or the color of the eggs  14 . Thus, all that remains is the non-egg objects  16  or debris. The primary function of the processor unit  64  is to detect non-egg objects  16  or debris and prevent those objects from entering other parts of the production process. The processor unit  64  also identifies the foreign objects  16  in space and can predict in real-time where the object  16  will be later to trigger appropriate inspection events. The processor unit  64  also analyzes the captured image through different inspection levels and can create the necessary debris or shutoff signals depending on the application, and/or provide information to the operator of the equipment regarding objects  14 ,  16  in the captured images. 
     Once the processor unit  64  identifies a non-egg object  16  or debris, the processor unit  64  classifies the objects with colors other than the color of the conveyor and the color of the eggs as debris (collectively non-egg objects and debris referred hereinafter as debris  16 ). The processor unit  64  measures a size of the debris  16 . The alarm signal is produced when measurements of the debris  16  exceed a predetermined value. 
     The processing unit  64  also images the debris  16  to create a debris image. The image of the debris  16  is then compared to a shape stored in a database. If the image of the debris  16  matches a shape in the database, the alarm signal is modified based on what type of debris  16  is identified. This is done because some debris  16  is more damaging to equipment downstream than other debris  16 . A non-exhaustive list of objects that are in the image database include wrenches, screwdrivers, light bulbs, cell phones, body parts of chickens and the like. The alarm signal may also be modified if the debris  16  does not match an image stored in the database of the processing unit  64  but is measured to have a size greater than a predetermined value. 
     More specifically, a first inspection level detects all debris  16  on the conveyor  12  and triggers the audible alarm  66  and visual alarm  68  if debris  16  is detected. The processor unit  64  is programmed to ignore the different background noise beneath the eggs  14  on any of the types of conveyors  12  used, including for example seams of a conveyor belt. As stated above, the debris detection system  10  may include a backdrop that is installed below or within the conveyor  12  to help reduce the amount of extraneous colors that may be captured in the images. 
     A second inspection level uses a library of vision tools as known to those skilled in the art with customized input parameters. A preloaded database of colors is used to filter out the conveyor  12  and the eggs  14  from the image. The debris  16  will remain in the image. From there, the processor unit  64  filters out the conveyor  12  and the eggs  14 , leaving only the debris  16 . By focusing on areas other than the eggs  14 , the processor unit  64  can operate much quicker than the systems that focus on the eggs  14  as well as the debris  16 . 
     A third inspection level allows for image matching. The processor unit  64  matches debris  16  in the captured images to preset images stored in a preloaded database of known foreign objects. These objects are typical objects that can be found in egg production environment, such as conveyor parts, tools, poultry feeding equipment, light bulbs, poultry body parts, etc. In one embodiment, there are twenty (20) objects that the system will learn to identify. It should be appreciated by those skilled in the art that the system is not limited in how many objects it will be able to learn and identify. 
     Based on the inspection levels above, the audible  66  and visual  68  alarms may be activated, along with the shutoff switch  72  and speed control switch  74 . Such events may be used independently or in tandem with the others depending on the requirements of the conveyor  12 . The processor unit  64  identifies the position of the debris  16  and can predict, based on camera trigger events, where the foreign object  16  will be later to trigger appropriate inspection events. Inspection events can be triggered immediately or up to a user adjustable, pre-defined time delay. Such event designations may include: Event 1 triggers the audible alarm  66 ; Event 2 triggers the visual alarm  68 ; Event 3 triggers a reduction in the conveyor speed; Event 4 stops the conveyor  12 ; Event 5 triggers another machine on the line to perform a secondary function, such as egg spacer devices, dividers, reservoirs, washers, picking robotic arms, etc.; Event 6 sends the captured image electronically to another device in the form of an alert, such as cell phone app, notifications, text, etc.; and Event 7 can trigger a text based alert giving written explanation or instructions to the recipient for follow-up action. 
     Once the debris  16  has been removed from the conveyor  12 , either manually or automatically, an acknowledgement signal must be sent to the processor unit  64  to continue normal operation. This acknowledgement signal can be sent manually via the reset button  70 , which may be in the form of a push button, may be another personal electronic device, or may be sent automatically via a secondary vision inspection system. 
     A touch screen monitor  76  is connected to the processor unit  64  to interface with the operator and to display vision or captured images. The images aid the operator in identifying potential debris alarms. The monitor  72  is secured within the housing  44  above the front door  46  for interaction with the operator. 
     An external computer and keyboard  78  may be hard wired or wirelessly connected to the system  10  for additional image processing and image saving. The external computer  78  can monitor the camera&#39;s functionality as well as storing device for recording any failed images for further review. The computer  78  can be connected to the internet and/or intranet via Wi-Fi, ethernet, or modem for remote support and/or software updates. 
       FIG. 5  illustrates a simplified flowchart of the processing steps performed by the processor unit  64 . The first step  80  shows the camera  60  being triggered in approximate  1  second intervals to capture an image. The processor unit  64  processes the image looking for foreign objects  16  based on color, shape, and size at step  82 . If a foreign object  16  is not detected at step  84 , the process loops back to step  80  to capture more images. If a foreign object  16  is detected at step  84 , the image is saved to a database at step  86 . The debris  16  is measured at  90 . Then, the shape of the debris  16  is compared to shapes stored in the database at  92 . It is then determined at  94  whether the debris  16  exceeds a predetermined size or matches a predefined shape. 
     Next, if the debris  16  does not exceed the predetermined size or match a predefined shape, a normal alarm signal is generated at  96 . The speed of the conveyor  12  is reduced at  100 . If the alarm is reset at  102 , the conveyor  12  is returned to normal operating speed at  104  and the processing unit  64  continues to capture images at  80 . If the alarm is not reset, the method loops back to step  100  and maintains a reduced speed for the conveyor  12  until the alarm is reset. 
     Returning to step  94 , if the debris  16  detected is larger than a predetermined size or has the shape of a predefined shape, a heightened alarm is sounded at  106  (the alarm may also include lights of various wavelengths to provide a visual alarm as well). The conveyor  12  may be stopped at  110 . When the alarm is reset, the method returns to step  80  and continues capturing images. If not, the heightened alarm is continued to be sounded at  106  until the matter is addressed through manual inspection and removal of the debris  16 . 
     The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. 
     Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.