Anne Fallon

GigE Vision - Gigabit Ethernet Cameras for Industrial Applications 
Camera interface standards for machine vision cameras have evolved over the last ten years. A decade ago, industrial digital cameras were very difficult to install and integrate into machine vision systems. The difficulty was largely because there were no camera interface standards. System integrators and end users desparately needed something more standardized.

In the late 90's, the AIA formed a camera interface standard based on channel link, a parallel bus designed particularly for laptop computer displays. By defining a standard cable and connector, together with some standardized signal assignments, the Cameralink™ standard was born. Around the same time, IEEE-1394 firewire cameras were conforming to a digital camera interface standard called DCAM, now more commonly known as IIDC. The DCAM (IIDC) camera interface standard went further than Cameralink in that it not only defined a standardized hardware interface but also defined a standardized software control interface making DCAM-compliant firewire cameras truely plug and play. Until recently, these two interfaces have dominated the industrial digital camera market.

However, there is a new interface standard that will soon dominate the industrial camera market. The AIA GigE Vision™ standard for Gigabit Ethernet cameras is now the state of the art interface for high-performance digital cameras for machine vision and industrial applications.

What is Gig-E? 
GigE, or Gigabit Ethernet, is a particularly fast version of Ethernet which everyone knows and loves. Every one is familiar with Ethernet because it is the ubiquitous means of connecting a computer to a network. Standard Ethernet has a maximum data rate of 10 megabits per second (Mbps) and Fast Ethernet has a maximum data rate of 100 Mbps, but Gigabit Ethernet is much faster at 1000 Mbps. Standard Ethernet and Fast Ethernet are too slow for streaming uncompressed image data, and way too slow for machine vision cameras. Gigabit Ethernet (GigE), however, with its maximum data rate of 1000 Mbps, or 1 gigabit per second (Gbps) is capable of handling streaming image data and providing reliable transmission of image data from high performance machine vision cameras such as the Gigabit Ethernet cameras from Baumer and Imperex. These GigE cameras are capable of streaming data at a sustained rate of 125 megabytes per second over their gigabit Ethernet interface.

What is GigE Vision? 
The GigE Vision™ standard from the AIA is an interface standard for high-performance machine vision cameras that is widely supported in the industrial imaging industry. GigE (Gigabit Ethernet), on the other hand, is simply the network structure on which GigE Vision is built. The GigE Vision standard includes both a hardware interface standard (Gigabit Ethernet) and standardized means of communicating with, and controlling, a camera. The GigE Vision camera control registers are based on a command structure called GenICam which is administered through the European Machine Vision Association (EMVA). GenICam seeks to establish a common camera control interface so that third party software can communicate with cameras from various manufacturers without customization. GenICam is incorporated as part of the GigE Vision standard, so any truly GigE Vision-compliant camera also complies with GenICam. GigE Vision is analogous to Firewire's DCAM (IIDC) and has great value for reducing system integration costs and for improving ease of use.

What is so great about GigE Vision and Gigabit Ethernet? 
GigE Vision is quite exciting because it provides many features that are unavailable in other camera interfaces. The combined features of high data rate (required for uncompressed video or imaging applications), ubiquitous computer interface hardware, low cost cabling, and widespread popularity make Gigabit Ethernet an attractive interface option for machine vision cameras. With the advent of GigE Vision, a standardized camera communication protocol from the Advanced Imaging Association (AIA), GigE has become more attractive still. Here are a few of the compelling benefits of GigE Vision-compliant cameras:

• Gigabit Ethernet ports are common on PCs and laptop computers, so there is no need for special interface cards or expensive/complicated frame grabbers in order to operate a GigE Vision camera.
• GigE provides high bandwidth to transmit uncompressed image data from a camera to a host computer in real time at speeds that exceed the requirements of most industrial machine vision applications. This negates the need for complex and expensive interfaces like Cameralink.
• Gigabit Ethernet provides a high performance camera interface to convey control and image data over long cable lengths. Cable lengths up to 100 meters long using inexpensive CAT5e cabling are possible. Even longer distances are possible using switches or fiber optics. Such long cable lengths far exceed the maximum cable lengths of Cameralink, firewire, and USB.
• GigE Vision is compatible with standard Gigabit Ethernet hardware allowing networking of cameras. This is especially useful in situations requiring multiple views and opens up new machine vision applications in Intelligent Traffic Systems (ITS) and public security imaging.
• GigE Vision allows multicasting of image data simultaneously to multiple computers for distributing the image processing load across separate computers.
• CAT5e or CAT6 Ethernet cables can be easily manufactured on-site using low cost cabling and tools. This feature is especially useful for outdoor installations where cameras may be mounted on poles or buildings and where the cable must be routed as the site demands.
• The new GigE Vision standard provides ease of use that surpasses other common camera interfaces.
• The fast successor to GigE, 10GigE, offers 10 gigabit per second (Gbps) data rates that when applied to cameras means that parallel interfaces like Camera Link are no longer be necessary even for high-speed applications

How are GigE Vision cameras different from other Gigabit Ethernet cameras? 
GigE Vision cameras, such as the Baumer TXG-Series and the Imperx Bobcat-Series, are machine-vision cameras that supply uncompressed image data in real time, usually at very high data rates, that is suitable for image analysis.

Most other types of Ethernet camera are not suited to machine vision because they supply only compressed image data, and that only at very limited data rates. Some so-called 'smart cameras' use Ethernet to transmit non-image data from the camera to a network, but these are generally application specific image sensors that are not suited to generalized imaging.

GigE Vision cameras such as Baumer TXG and the Imperx Bobcat GigE Vision cameras are specially designed to handle the dataflow in dedicated hardware providing uncompressed, very fast, very reliable data throughput in a form that is suitable for computer analysis.

Baumer and Imperx currently offers wide selection of CCD and CMOS machine vision cameras that conform to the GigE Vision standard providing an ease of use and integration that has not previously been available.

Using high speed video recording system to troubleshoot equipment failures presents several advantages over standard video. Most production workers are familiar with the type of video quality produced by traditional surveillance or security cameras. This footage tends to be grainy and lacks the detail required for accurate analysis. Security cameras are meant to be used in situations where a broad picture of the events that are unfolding is “good enough.” However, when it comes to assessing the problems afflicting delicate and complicated machinery, a much higher level of detail is required.

Given that packaging and other industrial equipment often operates at a high rate of speed, it is difficult or even impossible for a standard camera to produce images or video useful for diagnosing failures or other issues. It is for this reason that TroublePix and StreamPix is capable of interfacing with a wide range of cameras.

The Troublepix software is designed for factory floor applications or requirements needing a simple user interface. With TroublePix, you can acquire, view and review all within the same user interface. TroublePix provides features such as looping, Pre/Post triggering, event marking and much more.

The Streampix software is designed to capture from single or multiple cameras simultaneously. StreamPix 5 provides a complete management console for cameras, simplifying the setup, control and acquisition from any number and type of camera. The number of cameras supported is only limited by a condition wherein the combined data rate of the cameras exceeds the internal bus bandwidth or processor capabilities of the computer.

StreamPix 5

• Troubleshoot your production line or analyse hardware issues by imaging
• View events from multiple angles. Pinpoint the root cause of production line failures
• Operator friendly GUI and tools
• Lower down time and increased productivity
• Acquire from all cameras in a continuous loop or in pre-post loop with triggering for start stop. 4 or 8 cameras per computer
• Solutions available from 90 to 1000 frames per second. Resolution from 640 x 480 up to 4k x 4k
• Compatible with GigE, FireWire A or B, USB, Analog or CameraLink cameras from all major camera manufacturers.

TroublePix

• Designed for non technical operators
• Full screen mode, specially designed for use with touchscreen displays
• Solutions available for high speed from 60 to 1850 fps at VGA and high resolution
• Provides quick access to exposed camera/grabber features
• Multiple image display modes with zoom capability
• Lots of keyboard shortcut to speed operation without using mouse.

Further TroublePix information 

Accessories

Lenses 
Lighting 
Cameras 
Frame Grabbers

Description: A time of flight spectrometry technique, allowing the analysis of biomolecules and large organic molecules

Recommended Product: Stanford Research NL100

Goal: to know  the molecular weight distribution of a polymer sample Preparation of the sample: Solved in a solvant and mixed with a special component which absorbs UV (matrix)

Typical MALDI layout

Description: A remote-sensing technique that uses a laser light source to probe the characteristics of a target

Recommended Product: Quantel Brilliant

Atmosphere control Density Temperature Wind Pollution... Distance,  speed measurement Rayleigh, Mie scattering Raman scattering Fluorescence Doppler shift

LIDAR: Principle

The laser light, back-scattered by particules, is collected by a telescope. The time delay between emission and reception represents the distance (time of flight). The intensity is an image of the particules density Laser/telescope unit is mounted on a mobile system

LIDAR: Typical set-up

LIDAR: Applications

Anhui Inst. Of technology, China

• Localisation of pollution emission
• Measure of the limit layer of the atmosphere
• Measure of the diffusion of pollution clouds
• Ozone hole

• Aerosol measurements

“Nadezhda”, Russian ship sailing in Singapore area Measure of the atmosphere around the world

Laser Brilliant mounted on emission/reception telescope

LIDAR in operation

LIDAR: Commercial Systems

Elight Leosphere Polis Raymetrics

Description: A form of atomic emission spectroscopy in which a pulsed laser ablates a small amount of material from the sample's surface, the light from which is captured and analysed by a spectrograph

Recommended Product: Big Sky Ultra

Laser-Induced Breakdown Spectroscopy (LIBS) is a type of atomic emission spectroscopy in which a pulsed laser, generally a Q-switched Nd:YAG laser, is used as the excitation source.

The output of the laser is focussed onto the surface of the material to be analysed. The high power density at the surface (in excess of 1 Gigawatt per cm2) causes a fraction of a microgramme of material to be ejected from the surface (ablated) and a short-lived, highly luminous plasma is formed.

 
A typical LIBS experimental set up. Image courtesy of Applied Photonics .

The ejected material in the plasma dissociates into various ionic and atomic species. As the plasma cools, the excited ions and atoms emit optical radation. This emitted optical radiation is then analysed by a sensitive spectrograph and provides information about the composition of the material.

 
LIBS spectrum of gold ore. Image courtesy of Applied Photonics .

LIBS has many advantages over other techniques as it is virtually non-destructive (only a minute amount of material is ablated) it can be acheived remotely (up to 100m away) and the sample requires no preparation. Because of these advantages, LIBS can be particularly useful when working with hazardous materials or in harsh environments.

We work closely with Applied Photonics , who have succesfully used Big Sky Ultra lasers and Quantel Brilliant lasers in their LIBSCAN  and ST-LIBS  systems.

For more information about the analytical capabilities of LIBS, please visit Applied Photonics LIBS capabilities page . This is an ever-expanding database of information of LIBS data and spectra obtained from each element in the periodic table.

Description: Alignment of parts or machinery using a laser spot, cross or line

Recommended Product: Laserex Laser Diode Modules

Several properties of lasers make them perfect for alignment applications. They emit coherent light that can be well collimated into a straight, continuous, highly visible beam. Wherever high accuracy alignment of a sample, machine part etc is needed, the laser is the perfect tool.

The addition of a line generating optic will provide a thin light sheet that can further be used for 3D alignment and surface profiling. Below are some examples of were our lasers are used in industrial, automotive and manufacturing environments.

IMPERX new User Configurable Image Processor allows you to create your own secure, custom reliable In Camera Image Processing.

It's EASY 

• Pick a resolution and frame rate
• Pick an output (GigE, PoE, PoCL, HD-SDI etc)
• Add your image processing
• Use your custom camera

Features 

• Features the Altera low-power, low cost FPGA family (Cyclone-IV EP4CE75 or EP4CE55)
• Large number of hardware multipliers for high bandwidth/low latency concurrent digital image processing
• Available in industrial temperature range
• Vast parallel processing power for DSP applications (up to 200 multipliers at 260Mhz = 52GMAC/s)
• Image enhancement, preprocessing, data reduction, detection/recognition
• Text overlay, auto iris, auto exposure and auto focus based on real time image statistics
• Simplified system design (reduced PC CPU usage/utilisation)
• Easy and free programming over JTAG
• Many IP cores are available from Altera and third parties
• Extremely short design cycles

For more information, please click here to email or contact Clive Phillips or Mark Bambrick on 01582 764334.

Lambda Photometrics Ltd is a leading supplier of Measurement, Characterisation and Analysis solutions in areas including Lasers, Optics, Electro-optic Testing, Spectroscopy, Fibre Optics, Machine Vision, Optical Metrology, Instrumentation, Microscopy and Pulsed Xenon Light Systems.

TroublePix is ideal for factory floor, laboratory or outdoor applications requiring an easy to use GUI. Now compatible with Windows 64 bit. Using TroublePix you can acquire, view and review all sequences at the same time. Designed for non technical operators. Supports all standard cameras available in StreamPix. Compatible with gige, usb2, analog, camera link or firewire interface.

StreamPix is a digital video recording software that allows you to record live un-compressed or compressed video directly to your PC's RAM or hard disk drive in real time at up to 625 Mbytes/second. Create movie clips in AVI or other file formats such as bmp, tiff, multi-tiff, mpeg or jpeg format. StreamPix guarantees no image drops when acquiring a sequence.

Introduction

The application of measuring surface texture with a white light optical profiler has been well-known for many years. As the capabilities of optical manufacturing and precision machining increase, the production of ‘super smooth’ or ‘sub-angstrom’ surfaces has become more common, and quantification of these surfaces is critical for effective process control. The NewView™ 6000 series of optical profilers using Scanning White Light Interferometry (SWLI) with MetroPro™ software and patented FDA analysis enable rather straightforward quantification of surfaces with texture measured on the order of fractions of a nanometer. With good control over the measurement environment, proper selection of measurement parameters, and effective instrument calibration, quantification of surfaces with roughness measured in tens of picometers (1x10-12 m) is possible. With the NewView 6300’s best-in-class acquisition speed and resolution, areal measurement of supersmooth surface texture has never been so easy.

Understanding System Noise

The first step required in making quantitative measurements of super smooth surfaces is to understand that every measurement system has an inherent baseline system noise. This noise results from a number of factors including electronic noise, sensor noise, small irregularities in the reference surface, and small vibrations caused by changes in the measurement environment. For most samples, the measurement noise in the NewView can be essentially ignored, as the measurement value is much larger than the noise floor. However for very smooth samples, this is not the case. For these samples it is important to understand the noise sources and to control them as tightly as possible. Many sources of noise can be virtually eliminated or at least significantly reduced by both tightly controlling the measurement environment (acoustics, air currents, temperature, etc.) and also by performing a number of measurements and averaging them together into a single data file.

Environmental Controls 
The first task in setting up measurements for a super smoothpart is establishing control over the measurement environment. The ideal environment would be one which:

• is mechanically and acoustically quiet to minimize part vibrations;

• has tight temperature control to minimize sample and objective changes during the measurement period;
• has well controlled airflow to minimize air currents between the microscope and the part.

In order of importance, vibration, noise, and temperature rank at the top. When the objective working distance is small, airflow control may essentially be a non-issue after mechanics, acoustics, and temperature have been addressed. With long working distance objectives, however, air currents will be more critical to control.

Measuring the System Merit Function 
ZYGO has developed a process for quantifying the expected system noise as a function of measurement averages which we will call the System Merit Function (refer to the last page of this document for an illustration of this measurement method). The measurement process involves acquiring a number of measurements—typically 10 or more—with a given number of averages. Each of these data files are saved as D1, D2,…Di. These data are averaged together into one single file, Dse which represents the total system error during the measurement period. This Dse file is then subtracted from each of the component Di files to create an error map indicative of the expected system noise for a single measurement. The rms of the individual difference maps are recorded, and the mean and standard deviation are calculated for the series of differences. By adding twice the standard deviation of the series to the average rms of the series, the expected system noise for a given number of measurement averages can be estimated with good confidence. This process can be automated by using standard MetroPro and some very simple MetroScripting. An example application is available upon request from ZYGO.

Predicting System Noise 

Once the value of the System Merit Function for measurements with no averaging is known, the predicted system noise for a specific number of averages can be predicted using the formula.

where SN1 is the system merit value measured with no measurement averages and AVG is the desired number of averages. For larger numbers of averages taking a longer time period to measure (typically greater than 32 measurements) this prediction can only hold true in very well controlled environments. For critical applications, it is recommended to test the measured noise floor against the predicted value and ensure that the environment is controlled well enough – morewell-controlled environments will generally require fewer averages. In the event that the environment is not satisfactory, the line for the measured values in Figure 1 will typically turn upward again and diverge from the predicted values. If a noise floor associated with averages beyond the upturn point were desired, it would be necessary to further improve the environment.

Figure 1 –Excellent correlation is observed between predicted and actual system noise on the NewView 6300

Phase Res - Which Level?

Depending upon the smoothness of the surface to be measured, it may be necessary to increase the internal precision of the calculations made by the MetroPro software. Starting with version 8.1.1, MetroPro allows for three levels of precision with the Phase Res Measurement Control—Normal, High, and Super.Normal is the lowest resolution—useful primarily for large steps and rough surfaces. High is the standard setting for most typical measurement situations using scans up to 150µm and texture down to approximately 0.050 nm. The newest and highest precision setting, Super, enables measurement of very smooth surfaces using a large number of averages. Only very smooth surfaces will require the use of Super. This should be taken into consideration when determining baseline system noise.

What Noise Floor do I Need?

There is no one right way of selecting the number of averages (and by extension, the noise floor) for a particular application. For rougher surfaces, where the surface is measured in tens of nanometers or more, striving for a system noise on the order of 10x lower is often recommended. However for a surface which is on the order of 0.05 nm (0.5 Å) achieving a noise floor 10 times lower would theoretically require approximately 3000 averages! Rather than a hard and fast rule, a more empirical rule of thumb employed by ZYGO is that the lowest practical noise floor for an application is recommended, but that system noise should be at least 2 to 4 times smaller than the desired measurement surface features.

System Error Characterization

After determining the phase resolution and the number of averages required for the desired noise floor, it is recommended that the user perform a system error characterization. This process entails measuring a number of physical locations on an optical grade flat using the desired number of averages per site. 
Typically, at least 8 distinct sites with no overlapping regions are recommended for generation of a system error file. For specific information and procedures for creating a system error file, please refer to the NewView MetroPro Microscope Application Booklet, OMP-0360 or Section 8, MetroPro Reference Guide, OMP-0347. The error map created will then be subtracted from each of the surface measurements made on the actual sample.

Figure 2 - A graphical representation for the process of measuring the System Merit Function

Conclusion

Using the methods and procedures described here, ZYGO has demonstrated the capability of measuring surfaces smoother than 0.05 nm. Tightly controlling the measurement environment, selecting an appropriate internal precision, and choosing the number of phase averages based on the System Merit Value all combine to provide the highest quality surface texture measurements available from an optical profiler.