Systems and methods for locating a pattern in an image

#The invention relates to systems and methods for computer imaging, and more particularly to systems and methods for locating the position of an image having a degraded or eroded portion.

#Machine vision systems exist today that can allow for the automation of many manufacturing tasks, such as product assembly and inspection. To this end, machine vision systems typically include a camera that can be disposed above a workpiece, such as a computer board being assembled or an item being inspected. The camera can connect to a frame grabber board that can be incorporated into a computer workstation. Under the control of software operating on the computer, the camera can capture images of the workpiece and the frame grabber board can generate image frames, each of which can be stored as a computer file that can be processed by the software running on the computer workstation. The software operating on the computer workstation can analyze the image files to identify and locate within the image patterns that are known to the system. In this way, the machine vision system can determine the presence or absence of particular items within the image as well as the location of those items. This information can be provided to a manufacturing device, such as a solder tool, to allow the manufacturing device to perform its function such as by further assembling components to a computer board.

#Although machine vision systems work quite well, challenges still remain. For example, the quality of images generated by a camera depends in part on conditions that can vary uncontrollably in the manufacturing environment. For example, the quality of an image generated by a camera turns in part on the quality of background lighting. However, in the manufacturing environment the background lighting can change constantly. This in turn can result in differences between image frames collected by the machine vision system. In particular, dark spots and reflective spots within the image can vary from frame to frame, thereby making it difficult to recognize or locate a known pattern within the image. For example, during a metal processing step, a solder joint can be polished to a highly reflective finish. Under some lighting conditions, the solder joint can appear as a solid brightly lit ball. However, under other conditions shadows can appear on the solder joint causing an image to form that looks like a partially clouded ball. For either image, the machine vision system is provided with the challenge of identifying the solder joint ball within the image. However, the differences between images can make it difficult for the machine vision system to recognize or locate the degraded solder joint image.

#The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof, with reference to the accompanying drawings wherein;

#FIG. 1 depicts a system according to the invention for locating a pattern within an image;

#FIGS. 2A and 2B depict respectively and pictorially one example of an image and a degraded image of the type that can be captured by the system of FIG. 1;

#To provide an overall understanding of the invention, certain illustrative embodiments will now be described, including a system for searching through an image to locate a selected pattern therein. However, it will be understood by one of ordinary skill in the art that the search and locate systems described herein can be adapted and modified to provide image reconstruction systems, image recognition systems, or for any other suitable application. Moreover, it will be recognized that additions and modifications can be made to the systems and methods described herein without departing from the scope of the invention.

#FIG. 1 depicts a first system 10 for determining the position of a pattern within an image. Specifically, FIG. 1 depicts a system 10 that includes an image capture system 12 and a data processing unit 14. The image capture system 12 includes a camera element 16 and a work table 18 on which a work piece 20 sits. The image capture system 12 couples by the data path 22 to the data processing system 14. The data processing system 14 includes a frame grabber card 24 for capturing images provided by the image capture system 12, and further includes a display element 28 that can display an image, such as the depicted image 30, which can be representative of the image captured by the image capture system 12. It will be recognized by those of ordinary skill in the art that the imaging system 12 can be a conventional imaging system of the type commonly employed for industrial imaging applications. Thus, it will be understood that the invention provides systems and methods that can work on a wide variety of platforms and that a particular hardware platform is not required.

#For example, the depicted camera 16 can be any suitable camera and the actual camera selected can vary to meet the criteria of the imaging application at hand. Suitable cameras are available commercially. The camera 16 can generate individual image frames as well as image frames that can be provided as a data stream to the data processing system 14. On-chip micro lenses can be present to increase sensitivity. Optionally, the camera can have its own built-in frame store which captures and outputs full-frame images in real time. The depicted camera 16 couples to the data processing system 14 via the depicted data path 22. Such a data path can be provided by the camera, such as an RS-422 digital signal output for interfacing with external image processing system, such as a commercial frame grabber.