Old Anilox Inspection Technology versus New Technology; White Light Interferometry versus PIXELOC? Spectral Scanning

We get asked all the time, “What is the difference between White Light Interferometry versus PIXELOC? Spectral Scanning?

What is White Light Interferometry?

White Light Interferometry is nothing new and in fact has been around for more than 100 years and was invented by German physicist Albert Michelsen in 1881, it has been used for many years in many industry sectors, but predominately in controlled laboratory settings.

White light interferometry is an optical imaging method that utilizes the interference of white light to measure surface profiles. The technology combines two beams of light: one from a reference mirror and another from the surface being measured. When these two light beams are mixed, interference fringes are produced that interact with the surface profile, providing measurements.

While WLI has been a staple in various industries and controlled laboratory settings, newer technologies like PIXELOC? have emerged over the last 25 years. The advantage of PIXELOC? lies in its continuous evolution and improvement due to its relatively recent introduction. This allows for advancements in precision, speed, and the ability to detect finer details.

Despite the historical significance of WLI, White Light Interferometry devices on the market are comparatively inferior in terms of image modelling and the ability to detect issues such as ceramic damage. PIXELOC? technology, being more recent, can benefit from ongoing research and development to address limitations and enhance its capabilities.

What is PIXELOC? Technology?

PIXELOC? is the trademark associated with Troika Systems' AniCAM HD? positional closed-loop feedback system. In the realm of measurement systems, a crucial aspect is ensuring that data is derived from a movement originating from a known point, rather than a subjective point set by the user as in WLI technology.

The AniCAM HD? boasts remarkable resolution, allowing measurements in precise 0.25um steps. The patented PIXELOC? technology ensures uniformity across each AniCAM HD? device, making them identical and reliable for providing consistent results year after year. It's essential to note that PIXELOC? is exclusively available on the AniCAM HD? model.

What are the main differences when it comes to image capture?

White Light Interferometry

Pros:

• Can convey a specific artistic or design style.
• Requires less computational power, making it more accessible and faster.
• Easier to create for certain types of content.

Cons:

• Depth can be subjective depending on the user.
• Lacks realism compared to true 3D imagery.
• Limited in conveying subtle details.
• Not suitable for applications where vibration or light can interfere with the settings.

True PIXELOC? 3D Imagery:

Pros:

• Realistic representation of objects and scenes.
• Accurate depth perception.
• Natural lighting and shading effects.
• Often provides a more immersive experience.
• Is not affected by vibration or light interference.

In terms of 3D Visualisation which would you prefer to see, true 3D imagery or harsh rendered imagery like the below?

Troika Systems acknowledge the rights and credit to the lawful owners of images used; no copyright infringement intended.?

And 2D?

White light interferometry versus PIXELOC? Technology

Advantages & Disadvantages

Indeed, white light interferometry is highly sensitive to vibrations and environmental conditions. The precision required for the interference patterns to be accurately interpreted demands stable and controlled settings. Here are some key points related to the sensitivity of white light interferometry:

Vibration Sensitivity:

• White light interferometry relies on the interference of light waves, and any external vibrations can disrupt the delicate interference patterns.
• To achieve accurate and reliable measurements, it is essential to minimize vibrations in the surrounding environment.
• In applications such as press rooms, where machinery and equipment may generate vibrations, maintaining a vibration-free setup is challenging but critical.

Table and Mounting Requirements:

• The need for vibration-free tables and precise upright mounting is a common requirement for white light interferometry systems.
• A stable and well-isolated platform helps prevent external vibrations from affecting the interferometric measurements.
• Mounting the equipment properly ensures that the optical components are aligned correctly and maintained in a stable position.

Controlled Environments:

• White light interferometry systems are often used in controlled environments, such as laboratories or clean rooms, where environmental factors can be carefully managed.
• Temperature stability and control are also important, as changes in temperature can cause material expansion/contraction, affecting measurements.

Applications in Stable Environments:

• Due to its sensitivity, white light interferometry is often employed in applications where environmental conditions can be controlled and kept stable.
• Industries such as semiconductor manufacturing, optics, and precision engineering commonly utilize white light interferometry in controlled settings.

In summary, the sensitivity of white light interferometry necessitates a controlled and stable environment, making it challenging to use in settings like press rooms where vibrations are inherent. Careful consideration of the environmental conditions and proper setup are crucial to ensure accurate and reliable measurements in applications that demand high precision.

The AniCAM? with PIXELOC?Technology is designed to operate effectively in a noisy and vibrating press room environment. This is achieved through features that address the challenges posed by vibrations, making the device suitable for applications in such industrial settings.

Key aspects that contribute to its performance in these conditions include:

Vibration Dampening:

• Specialized settings and components that help dampen vibrations, ensuring accurate measurements even in environments with significant vibrations.

Robust Design:

• The device has a robust mechanical design that minimizes the impact of external vibrations and maintains stability during operation.

Adaptive Technology:

• Features adapt to and compensate for vibrations, allowing the device to continue providing reliable measurements even in dynamic environments.

Versatility:

• The ability to read upside down, versatility and adaptability to different orientations, making it more user-friendly in various practical situations.

PIXELOC? Technology:

The PIXELOC? technology contributes to the stability and precision of measurements in challenging environments.

This kind of adaptability is crucial for instruments used in industrial settings, where environmental conditions may not be as controlled as in a laboratory. The ability to function effectively in noisy and vibrating environments expands the range of applications for such devices, providing valuable measurement capabilities in real-world manufacturing scenarios, such as press rooms.

White light interferometry, like many precision measurement techniques, can be sensitive to operator-dependent factors. The manual determination of the starting point, especially when dealing with the bottom of the cell or the reference point, introduces a potential source of variability between different operators.

Here are some key points related to this user-dependent aspect in white light interferometry:

Operator Influence:

• The need for manual determination of the starting point means that the choice of this point can vary between different operators.
• If operators interpret or select the starting point differently, it can lead to variations in the recorded measurements.

Consistency Challenges:

• Achieving consistent and repeatable measurements across different operators can be challenging due to the subjective nature of selecting the reference point.
• Variability in the starting point can result in discrepancies in the measured values.

Calibration Procedures:

• Regular calibration of the system is essential to maintain accuracy. Calibration procedures should include the reference point determination to account for any drift or changes in the system.
• Addressing operator-dependent variations in measurement techniques is crucial for obtaining reliable and consistent results, especially in applications where precision is paramount.

PIXELOC? Technology represent significant advancements in automating the measurement process in comparison to traditional white light interferometry.

Here are some key features:

Automatic Surface Recognition:

• PIXELOC? Technology includes software that automatically recognizes the top surface of the object being measured. This eliminates the need for manual determination by the operator.

Automated Measurement Process:

• The software then proceeds to measure downward in precise 0.25um steps until it reaches the bottom of the cell. This automation reduces the potential for human error and ensures a consistent and accurate measurement process.

Volume Calculation:

• By measuring in increments and reaching the bottom of the cell, the software can calculate the volume of the object. This feature provides valuable information about the three-dimensional characteristics of the measured sample.

Auto-Focusing:

• The inclusion of auto-focusing in the PIXELOC? Technology further streamlines the process. Automatic focus adjustment eliminates the need for manual adjustments, reducing the chances of errors and enhancing the efficiency of the measurement workflow.

Elimination of Guesswork:

• With the automated processes and auto-focusing, PIXELOC? Technology removes the guesswork traditionally associated with selecting reference points and ensures a more objective and reliable measurement outcome.

These features collectively contribute to making the measurement process more user-friendly, efficient, and less dependent on the operator's skills. Automation not only reduces variability between different operators but also enhances the overall accuracy and reproducibility of the measurements. This can be particularly advantageous in industrial and manufacturing settings where precision and efficiency are crucial.

White light interferometry, while a powerful and high-precision measurement technique, has limitations when it comes to certain complex structures, especially those with breaks or disruptions in the wall structure.

Here are some points to consider:

Localized Measurement:

• White light interferometry typically provides localized measurements of surface profiles. It excels at capturing fine details of surfaces but may not account for variations in structures beyond the localized measurement area.

Challenges with Disruptions:

• Breaks or disruptions in wall structures may introduce challenges for white light interferometry. If the surface is not continuous or exhibits complex features, it might be difficult to obtain accurate measurements across the entire structure.

Volume Considerations:

• While white light interferometry can provide detailed information about the measured region, it might not inherently account for variations in volume due to structural breaks or irregularities.

Limited Field of View:

• The field of view in white light interferometry is typically limited to the region being directly measured. Any additional information about the structure outside this field may not be captured.

Understanding the strengths and limitations of white light interferometry is essential for choosing the appropriate measurement technique for specific applications. While it excels in capturing detailed surface profiles with high precision, it may not be the ideal choice for scenarios where understanding the entire volume of a complex structure, especially with breaks or disruptions, is critical.

In situations where the surface texture or irregularities are larger than the measurement precision of a device, the accuracy of the device becomes less relevant. This is often referred to as the "signal-to-noise ratio" in metrology and measurement science.

Here are some considerations in such cases:

Dominance of Surface Texture:

• If the natural texture of the surface is deeper than the measurement precision, the device may primarily capture information about the texture rather than the finer details that fall within its specified accuracy.

Resolution vs. Accuracy:

• The resolution of a measurement device refers to its ability to distinguish between closely spaced features, while accuracy is its ability to provide measurements close to the true value. In situations where surface texture dominates, resolution becomes more important than absolute accuracy.

Practical Considerations:

• For applications like road measurements where surface textures, such as those on a tar road, may have variations larger than the desired precision, the practical effectiveness of the device might be more critical than its theoretical accuracy.

Consideration of Measurement Range:

• Devices with a broader measurement range might be more suitable for scenarios where the surface features vary significantly in depth or texture.

Adaptability to Surface Characteristics:

• It's important for measurement devices to be adaptable to the specific characteristics of the surface being measured. Some devices may be better suited for smooth surfaces, while others excel in capturing details on textured or irregular surfaces.

In summary, in practical applications where surface texture or irregularities dominate, the relevance of extreme accuracy may diminish, and other factors such as resolution, adaptability, and the ability to capture relevant information become more crucial. Understanding the nature of the surface and the specific requirements of the application is key in choosing the most suitable measurement device.

The analogy with measuring potholes on a road is a great way to illustrate the importance of methodology and sampling strategy in measurements. Indeed, the choice of methodology can significantly impact the results obtained.

Here are some key points:

Sampling Strategy:

• The methodology for measuring potholes—whether you take an average of 30 holes, 10 holes, or measure just one—represents different sampling strategies.
• The choice of sampling strategy should be based on the specific goals of the measurement and the variability in the characteristics of the potholes.

Representativeness of Results:

• The representativeness of your results depends on how well your chosen methodology reflects the overall condition of the road.
• A larger sample size tends to provide a more representative picture of the entire road, but this comes with practical considerations such as time and resource constraints.

Precision vs. Accuracy:

• Precision refers to the consistency of measurements, while accuracy refers to how close the measurements are to the true values. Your chosen methodology may affect both precision and accuracy.
• Averaging a larger number of measurements can improve precision, but it may not necessarily improve accuracy if the chosen sample is not representative of the entire road.

Methodological Consistency:

• Regardless of the chosen methodology, it's crucial to apply it consistently to ensure that results are comparable over time or across different measurements.

Application to Anilox Measurement:

• In the context of anilox measurement, the choice of methodology, such as the number of data points or cells measured, can similarly influence the results obtained.
• Considerations may include the variability in cell volumes, the level of detail needed, and the practical constraints of the measurement process.

In summary, any measurement is not inherently "wrong" based on methodology; rather, it reflects the specific approach you've chosen. The key is to be transparent about the methodology used and to ensure that it aligns with the goals of the measurement and the characteristics of the system being studied. This ensures that results are meaningful and can be appropriately interpreted within the context of the chosen methodology.

In industries where tolerances and variations in cell volumes of Anilox rolls can be significant. Manufacturers specify variations of up to 20%, the emphasis may shift from absolute accuracy to consistency and reliability in the measurement process.

Here are some considerations:

Relative Measurements:

• When variations in cell volumes are relatively large, the focus may shift towards obtaining measurements that are consistent and relative rather than relying on absolute accuracy.
• The goal becomes to identify trends, changes, or variations in cell volumes rather than achieving precise absolute values.

Process Control and Monitoring:

• Anilox measurement in this context may be more about process control and monitoring, ensuring that the Anilox rolls meet certain quality standards and that any variations are within acceptable ranges.

Repeatability and Reproducibility:

• The emphasis on measurement consistency, repeatability, and reproducibility becomes crucial. It's important that measurements taken by different operators or at different times yield comparable results.

Understanding Variability:

• Understanding the inherent variability in the manufacturing process and the acceptable tolerances helps in setting realistic expectations for measurements.

Quality Assurance:

• The Anilox measurement process may be more about quality assurance and ensuring that the Anilox rolls meet the specified standards for a particular application or printing process.
• In situations where accuracy is less critical due to specified tolerances, the reliability and consistency of measurements become paramount. This aligns with the broader concept of metrological performance, which includes aspects such as trueness, accuracy, precision (repeatability and reproducibility), and reliability.
• It's also worth noting that the choice of measurement tools and methods should align with the specific needs of the industry and application. Understanding the context in which the measurements are used is crucial for making informed decisions about the measurement process.

PIXELOC? with the patented Reflection Balance System (RBS?) addressing challenges in applications like Gravure Cylinder Inspection or Flexoplates highlights the adaptability of this technology to diverse and challenging environments.

Here are some key points:

Adaptability to Various Applications:

• White light interferometry, while highly precise, may face challenges in certain applications like Gravure Cylinder Inspection or Flexoplates due to reflections and other factors.
• PIXELOC?'s Reflection Balance System (RBS?) addresses these challenges, showcasing the adaptability of the technology to a broader range of applications.

Compensation for Reflections:

• Reflections of light can introduce challenges in obtaining accurate measurements. The RBS? in PIXELOC? compensates for these reflections, indicating a level of sophistication in handling complex optical scenarios.

Automatic Adjustment of Lighting:

• The automatic adjustment of lighting by PIXELOC? in response to reflections suggests a dynamic and responsive system. This adaptability is crucial in applications where the surface characteristics can vary, and reflections may interfere with measurements.

Enhanced Versatility:

• The ability of PIXELOC? to handle reflection-related challenges enhances its versatility, making it suitable for a broader spectrum of applications beyond traditional white light interferometry.

Optical System Optimization:

• The optimization of the optical system, especially in dealing with reflections, demonstrates a commitment to refining and improving the technology for practical use in various industrial settings.

Industry-Specific Challenges:

• Gravure Cylinder Inspection and Flexoplates often pose unique challenges, and the tailored features in PIXELOC?, such as the RBS?, indicate a focus on addressing these specific challenges in the printing industry.

In summary, the incorporation of the Reflection Balance System in PIXELOC? showcases advancements that makes the AniCAM HD? more versatile and applicable in environments with challenging optical conditions. This adaptability is essential for meeting the diverse needs of different industries and applications.