Pharmaceutical Industry Applications of Machine Vision
| By: Nello Zuech, Contributing Editor
The pharmaceutical industry was one of the earliest adopters of machine vision, as the incentives to guarantee product integrity and safety have always been foremost in this industry. Early on, the importance of date and lot codes was recognized to yield cost effective product recalls when necessary, however, simply applying date and lot codes was not enough, given character quality concerns associated with then existing imprinting processes. Machine vision became the ideal technology to verify codes and validate legibility of the codes. While some of the early primitive machine vision algorithms provided some guarantee of code correctness and quality, machine vision systems today have become more sophisticated with the ability to handle more compute-intensive algorithms, allowing date and lot code verification to become even more reliable.
The pharmaceutical industry was one of the first to embrace color-based machine vision. This was driven by the need to verify that the correct birth control tablets were in the specific location in the blister package. The colors that were used were challenging for machine vision systems because they were often subtle intensity variations of the same hue. Other challenging color-based machine vision applications in this industry included inspecting for 'foreigners' in solid dosage manufacturing and detecting particles in solutions. The very early 'machine vision' versions were based on analog techniques. As machine vision technologies improved, these analog systems were quickly replaced with digital imaging-based systems, or machine vision systems.
Companies offering application-specific machine vision products were asked to contribute to this article. The following kindly responded:
- Jon Donovan, Product Manager, Symetix (Walla Walla, Washington)
- Ron Lawson, President, SVResearch (Harrisburg, Pennsylvania)
- Bill Cuniff, Sales Manager, Uhlmann VisioTec GmbH (Laupheim, Germany)
1. What specific machine vision applications related to the pharmaceutical industry do your products address?
[Jon Donovan – Symetix] Symetix offers Vantyx and OptyxSG systems. Vantyx is dedicated to high-performance color inspection for tablets in blister packs. OptyxSG systems are used to inspect softgels and tablets, for both pharmaceutical and nutraceutical products. OptyxSG is a bulk inspection system; products are fed continuously and inspected products are ready for packaging.
[Ron Lawson – SV Research] We address the following applications in the pharmaceutical industry:
A. Cap / Seal inspection
B. Empty glass inspection
C. Stopper position inspection
D. Powder / Lyo / Liquid fill inspection
E. Seal surface inspection
F. OCR / OCV inspection
G. Serialization Track and Trace
H. E-pedigree marking inspection
I. Component inspection (Stoppers / Caps / Glass)
J. Particle Inspection
K. Final product inspection
L. Box / Label inspection
[Bill Cuniff – Uhlmann VisioTec GmbH] VisioTec vision inspection systems address pharmaceutical product inspection in blister formats on thermoformers. We employ matrix camera systems for product presence (simple b&w), product presence, color, shape and physical conditions (color) and a unique line scanner camera system for confirming product color, shape and physical conditions in a reflective (aluminum forming material) or same color background as the product.
2. Can you describe your application-specific machine vision product line that addresses applications in the pharmaceutical industry specifically and discuss how you differentiate your products that address these applications, if you offer more than one?
[Ron] All of the applications listed above use the same CFR 21 Part 11 compliant interface. All inspections can be directly connected to line management systems. Similar material handling systems are used and all inspection solutions include integrated material handling designed specifically for vision inspection.
[Bill] VisioRead: A matrix camera system available in black and white or color. This system is utilized for primarily for print inspection and presence detection. For print it confirms print on the lidding material of thermoformed product is correct. For presence it can be used for confirming position, location and print on vials and syringes. For vials it can confirm stopper position and label position and print verification. For syringes; plunger placement, tip and other components can be verified for presence and position. Tools are what makes this all possible, the software for using these tools while complex, is very user friendly.
VisioPan: A simple black and white matrix camera system that uses light from below for product presence, shape, foreign and cracks in a thermoformed blister.
VisioChrom: A color matrix camera system, for product color, shape, foreign and cracks in a thermoformed blister.
VisioChrom HR: A high-resolution color scanning system for product color, shape, foreign and cracks for product in aluminum or other highly reflective thermoformed blisters. Also provides the ability to inspect for same parameters.
VisioNIR: Provides a matrix camera (same as VisioChrom) and NIR sensor for visual and molecular level product inspection in thermoformed blisters.
NIR: 100% product inspection at molecular level to confirm product is what it is supposed to be. A typical example of installation is on a tablet press inspecting each and every individual tablet on a tablet press with speeds up to 350,000 per hour. This same inspection can be used for liquid and other Pharma products as well.
3. What are some of the specific application issues (throughput, appearance variables, specularity, position variables, line integration issues, etc.) that your system address?
[Bill] Uhlmann VisioTec GmbH has its product inspection roots traceable to thermoformer and ancillary upstream and downstream systems such as cartoners, labelers and casepackers. VisioTec provides 100% inspection, however there can be challenges. Our software platform prompts the 'teach-in' of the product. Software tools overcome appearance variables by allowing better blending of product color area. Additional tools aid in specularity and position variables. For unusual specularity issues, hardware modifications for the camera or lighting are sufficient. However, there are extreme lighting conditions where reflectance is an issue. Specialized High Resolution Line Scanner equipment overcomes these difficult lighting conditions by looking at slices of the image as opposed to the whole (matrix) image. These small slices provide better resolution and lessen lighting reflectance; polarized filters can further reduce lighting issues.
[Jon] All of our systems inspect tablets and capsules for correct color, size and shape. Capacity varies by tablet or capsule size, but we do applications at rates up to 1,000,000 doses/hour. We offer complete line integration services including engineering drawings, line controls, and integration of conveying, weighing, counting, and packaging machinery.
[Ron] All of our systems automatically compensate for variations in lighting and product position. Most machines are designed with a test/Validation mode that allows product to be circulated through the machine to collect detection data. Every system includes a “Regression test” mode that allows libraries of images, both good and defect, to be re-run to test the effect of any vision system adjustment.
4. Can you provide some insight into the principles embedded in your machine vision products?
[Jon] The OptyxSG vision systems are built to perform high-speed inspection of randomly-presented objects, employing the proprietary cameras and processing components of our parent company, Key Technology, Inc. The User Interface is designed to facilitate rapid teaching of new products, and for rapid changeovers from stored product setups. All of our systems are used in pharmaceutical product applications and have been validated, including requirements for 21 CFR 11.
[Ron] Our vision system is a PC-based system with our SVObserver vision processing software. The complete solutions utilize the vision system to process images and determine pass/fail status. We use PLC processors to control the machine, track products through the machine and control the rejection of defects. A separate PC running the HMI is providing the CFR 21 part 11 compliant interface and integration to line management. By isolating the specific functions to their processor, it is easy to identify and manage changes. A change to the PLC will not require re-testing the vision processor or the HMI system.
[Bill] The systems are PC based and able to interface with a shift register for tracking. Constant monitoring of existing proven technology is evaluated and may or not be implemented into systems. Recent improvements increase stability and reliability by using portions of Windows relevant to running and safeguarding the system and use of non-mechanical hard drives for better performance.
5. Can you provide some insights into the specific hardware/software implementation designs of your machine vision products?
[Ron] Over the years, we have been asked many times to add a camera to existing conveyors or machines. These efforts look simple at the beginning; however, the conveyor or existing machine was not designed with inspection in mind. The end result is usually a compromise that does not yield the best performance. With the systems we are now providing, we include the required material handling as part of the vision system. This allows the complete performance of the system to be tested before integrating it into the production line. Normally, the additional money spent for the material handling is offset by the reduced integration time and minimized line down time.
[Bill] The VisioChrom HR has many unique features differentiating it from other matrix cameras. HR meaning, high resolution, utilizes a line scanner, examining product line-by-line product inspection. This also allows us to use a smaller light box, minimizing reflectance of light on aluminum or other challenging backgrounds.
[Jon] The OptyxSG system is a complete, integrated machine that uses proprietary Key Technology cameras, processors and software, and is designed to receive, inspect and discharge products continuously. Products are presented on a conveyor belt. Each tablet or capsule is inspected on the belt, and is also inspected from the bottom, as it is launched from the end of the conveyor. After these two inspections, failed products are ejected. The OptyxSG includes capabilities to verify ejection function, self-monitor all critical internal systems, and provide complete logs of user activities, inspection results and machine status. Mechanical design features simplify clearing and cleaning to enable rapid product changeovers -- in keeping with the system's design objectives to facilitate high-volume and continuous product inspection.
6. What new machine vision products or advances to your existing products have you introduced in the past year? Products specifically targeted at the pharmaceutical industry?
[Bill] We have combined our proven existing product vision inspection systems with another product inspection technology, NIR. We call this, VisioNIR -- Visio for vision inspection of the product and NIR for the near infra-red molecular inspection of the product. The combination of these two technologies provides 100% assurance that the product is visually (color, shape and condition) as well as product-content correct.
[Jon] The Vantyx and OptyxSG systems were introduced more than 12 months ago. However, we continually refine these systems and offer additional functionality through software enhancements, etc.
[Ron] We introduced the following recently:
- Powder / Lyo / Liquid fill inspection
- Serialization Track and Trace
- E-pedigree marking inspection
- Box / Label inspection
7. Historically, what were the barriers to the adoption of the type of application-specific machine vision systems you offer in the pharmaceutical industry and what are today’s barriers to more widespread applications of these machine vision systems?
[Jon] The OptyxSG addresses many of the historical barriers, which included low system capacity, expensive change parts, and too much time required to clear, clean and change over.
[Ron] Historical barriers have been systems deployed with poor performance. The expectation levels of this industry are higher than most others. Today, there are better informed customers that know the right questions to ask and that know better how to specify an inspection system.
[Bill] Marketing influences continue to play a major role in the challenges of product inspection due to color, shape and size differentiations. Color differences can be close to other different products or match product color with the same background blister material. Product formulation can influence the challenges of product vision inspection with multi-layered products or unique delivery systems within the product. Today's barriers are the challenges to traditional vision systems resulting in the incorporation of other technology such as NIR to overcome them. Combined product inspection technologies and continued inspection developments enable most of today's barriers to be overcome.
8. What advances associated with the technology infrastructure of your application-specific machine vision products has lead to more rigorous performance (reliability, repeatability, accuracy, etc.) in your newest products (optics, lighting, vision hardware, vision software, cameras, etc.)? And, what are the specific advantages of these advances in terms of price/performance?
[Ron] Although there have been many advances, I think the one that has had the most impact is LED lighting developments. As far as price/performance impacts, the old saying is still true “You get what you pay for.”
[Bill] Continued chip and lighting improvements, such as LED, have both improved lighting conditions and length of service, resulting in less replacement costs and reliability.
[Jon] A significant part of the underlying technology for the OptyxSG was developed for food processing applications. Because of this, and because food processing applications are very demanding, our system has very high reliability, repeatability and accuracy. And, because we can use the infrastructure and resources of Key Technology, we already had capabilities for supporting pharmaceutical applications, including system design and lay-out, specification, integration, qualification, training and service.
9. What changes in the underlying machine vision technology (vision engines, lighting, cameras, etc.) do you anticipate in the next 2 – 3 years that will yield even better performance?
[Bill] We expect the typical electronic developments to continue…smaller, faster and less expensive. We all share in those benefits; however the continued development of software tools to address new inspection challenges will be the real reward.
[Jon] Advances in machine vision hardware will result in enhancements for both performance and ease of use. Aside from that generalization, our internal development plans are confidential.
[Ron] We are researching many other technologies to determine their impact in pharmaceutical inspection. Not all are traditional vision technologies, but all have the requirement to process arrays of data such as X-ray, NIR spectrum analysis, etc.
10. How will those changes impact the pharmaceutical industry?
[Jon] We believe it will become a standard practice for pharmaceutical manufacturers to inspect all solid dose forms prior to packaging.
[Bill] With the R&D product development lean for the moment, pharma will continue to look to minimize costs and will directly benefit from improved technology and pricing. As external and internal influences affect them, such as FDA, Track and Trace, PAT and QbD, use of existing proven technologies will become more viable.
11. What are some market/process changes that are taking place in the pharmaceutical industry that are driving the adoption of application-specific machine vision systems?
[Ron] Reductions in work force combined with the increased desire to minimize liability.
[Bill] PAT and QbD are influencing the traditional vision-only based systems as they are 'dumb' systems, only confirming that what is 'seen' is correct. New technologies, such as NIR, 'smarten' the product inspection process by confirming that what is visually correct is also product-content correct.
[Jon] Consolidation, outsourcing and increasing efforts to make manufacturing operations efficient and faster will drive additional automation. And, processes are increasingly coming under review by regulatory agencies. In some cases, PAT initiatives may drive additional requirements.