Customer Solutions

Developing an Optical Character Recongition System with NI LabVIEW, Motion, and Vision

Author(s):

Steve McCool, Graftek Imaging

Industry:

Life Science

Product:

Data Acquisition, LabVIEW, Motion Control, PXI/CompactPCI, Vision

The Challenge:

Developing a quality assurance process to guarantee accurate labeling of medical and pharmaceutical products.

The Solution:

Building a LabVIEW-based system -- far exceeding human visual inspection -- that integrates image processing, motion control, and optical character recognition.

Introduction
Industrial automation applications frequently combine the need for computerized motion control and machine vision. Such applications often also require automated inspection of product labels to verify accuracy. The first pieces of the solution, the IMAQ PCI-1408 acquisition board and IMAQ Vision software from National Instruments, have been available for over a year. National Instruments recently provided the next piece of the puzzle - motion control products. Now Graftek Imaging, Inc. has completed the puzzle by providing optical character recognition (OCR) within LabVIEW. In this article, we describe LabLRead, an integrated LabVIEW machine vision, motion control, and OCR system recently delivered to a customer in the medical/ pharmaceutical industry.

System Requirements
The requirements for this system stem from stringent FDA regulations requiring the highest accuracy in labeling of pharmaceutical and medical products. Fortunately, the U.S. government tries hard to minimize the possibility of delivering mislabeled medicine and other single-use medical products to hospitals and patients. Medical product companies are gradually replacing human inspection, which is both tedious and error prone, with sophisticated automated systems. In this particular semiautomated application, we were required only to inspect the product labeling once, off line, after each change of product type on an automated processing line. The customer plans to add continuous line inspection for the next step.

The products to be inspected, destined for hospital use, are produced in "layups," physically connected sets of from two to eight units. Inspection of the label content and color for these multiproduct layups was the challenge presented to Graftek. Because of the high resolution required to identify label content, it proved to be most economical to successively move each individual product into the camera field of view for inspection. Hence the need for LabVIEW-based motion control.

System Configuration
Because the customer required verification of the color of the top part of the product label, we were required to use a color camera. To obtain the required overall resolution, we used a JVC TK-1370 (768 by 494 pixel NTSC and Y/C) color camera to inspect half of the label and a SONY XC-75 (1/2 in. format, 768 by 494 pixel) monochrome camera for the other half. Originally we planned to use a third-party color acquisition board, but National Instruments came to the rescue with the StillColor upgrade to NI-IMAQ. With StillColor, you can acquire true color images from NTSC or RGB color cameras using the "monochrome" IMAQ PCI-1408 image acquisition board.

In operation, the LabLRead system is highly automated. The operator places the multiproduct layup in a fixture and scans a computer-generated work order, which specifies the correct contents of a particular product run and the text that should be present on product labels. This work order contains either a printed product description or barcoded information. Once LabLRead recognizes the content of the work order, it begins to inspect the actual product to compare product labeling with the specified content. Both label text content and color regions are inspected to assure accuracy.

Via LabVIEW motion control, the product layup is moved laterally until the next product is directly under the cameras. This process repeats until the entire layup has been inspected. After completion of the inspection process, a test report label is automatically printed from LabVIEW on a miniature printer. The label contains product run identification information, the status of product inspection (pass or fail), and the reason for failure if any. This label is affixed by the operator on the work order as a permanent record documenting that the inspection was performed and archiving the results of the test. The entire process is completed in approximately 8 seconds.

The system uses an industrial computer, an Appro Pentium 166 (32 MB RAM), running Windows NT. Windows NT is becoming the operating system of choice for LabVIEW industrial applications. Installed in the computer are the PCI-1408 image acquisition board and an AT-MIO-16E-10 data acquisition board used for position sensing and motion control.

The LabLRead system illustrates the synergy of integrated image processing, motion control, and OCR all within the LabVIEW environment. Such a seamless, reliable, yet flexible inspection system could not have been readily developed outside of the LabVIEW environment. This application demonstrates once again that National Instruments-based systems are able to meet the challenges of critical industrial inspection. Moreover, we estimate that LabLRead was built at a savings of $60,000 versus off-the-shelf turnkey technologies.

For more information, contact Steve McCool at Graftek Imaging, Inc., 1825 Fortview Road, Suite 109, Austin, TX 78704, tel (512) 416-1099, fax (512) 416-1014, e-mail: mccool@graftek.com, web www.graftek.com.

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