Cameras in Machine Vision – Part 1

•  
• 1280 x 1024 pixels at 30 frames/sec.
• Low power consumption for design simplification and heat dissipation.
• Color or monochrome versions for application-specific flexibility.

7900 series

• 2K x 2K(high-resolution) precision imaging camera.
• Compact size and rugged construction.
• CameraLink output for simplified integration.
• Partial readout for even faster frame rates.

[Dr. Joachim Linkemann – Basler Vision Components] Basler has almost two decades experience in industrial imaging. Basler-VC designs and manufactures advanced vision components for industrial users. Machine Vision is one of our target markets.  Products include color and monochrome line scan and area scan digital cameras for high-speed and/or high-resolution applications.  Product designs are driven by industry requirements offering easy interfacing, compact size and a good price/performance ratio.  At Basler-VC, we pride ourselves on being a quality and a technology leader.  Continuous innovation is our strength and through it, we have given direction to the field of image processing technology.

Area scan cameras are offered with resolutions from VGA to 4 Megapixels and can operate at up to 500 frames per second.  Most cameras also include an Area of Interest (AOI) feature, which allows them to operate with higher frame rates at lower resolutions.  Our area scan cameras feature CameraLink® and IEEE 1394 connectivity.

Line scan cameras are offered with resolutions from 1024 to 8160 pixels, with data rates up to 120 Megapixels per second and with the CameraLink Interface.

[Christophe Robinet – Atmel] With over 25 years experience in imaging, ATMEL (formerly THOMSON TCS) is a key supplier of sensors and cameras serving the machine-vision market. Our AVIIVA™ and AKYLA™ line scan product lines cover resolution sizes ranging from 512 to 8K pixels, dynamic range up to 12 bits, data rate up to 160 MHz, monochrome or color, with LVDS or CameraLink®. These cameras are known for their excellent SNR, accurate positioning and versatile implementation modes.

ATMEL is now also recognized as the challenger in the line scan camera segment. ATMEL area scan offering includes the CAMELIA™ CCD camera with resolutions up to 8M Pixels, and ATMOS™ CMOS camera, featuring 1.3M (just released) and 2M (to come shortly) up to 60 frames per second in Camera Link format.

[Dave G. Gilblom – Alternative Vision] Two kinds:

1. Digital color cameras made by HanVision using the Foveon color image sensors.  LVDS or CameraLink outputs.  Two models with different resolutions and speeds – HVDUO-10M – 2268 x 1512 x 3 @ 4.5 fps and HVDUO-5M – 1420 x 1064 x 3 @ 7 fps.

2. Contact image line scanners up to 3 meters long in color or monochrome with integral LED illumination.  Resolution from 200 to 1200 dpi.  Scan rates from 5 to 40 KHz.  Operating distance from contact to 1.9 cm.  CameraLink interface.  Made by Tichawa Vision.

2. What are some challenges that you have offering products to the machine vision industry?
[John] Getting the word out that GigE cameras are available NOW.

[Ilias] Long design cycles, customization requests and a diverse list of requirements are major challenges faced in the machine vision market. Also, the lack of one industry-wide digital interface standard complicates the decision making process for new product lines and stretches engineering resources.

[Keith] Price/Performance ratios continue to decline as machine vision users expect high-performance cameras for less.  In addition the number of competitors has increased greatly contributing to price erosion on the market.

Certified System Integrator Program

Set Yourself at the Forefront of the Global Vision Market

Vision system integrators certified by A3 are acknowledged globally throughout the industry as an elite group of accomplished, highly skilled and trusted professionals. You’ll be able to leverage your certification to enhance your competitiveness and expand your opportunities.

GET CERTIFIED

[Marty] The challenge for Prosilica is to further provide excellent products and customer support at an affordable price, and to do all this better than our competitors.

[Gunnar] We are from time-to-time confronted with the question, why aren't industrial cameras priced the same as digital still cameras, when they use the same or similar image sensors?

[Loren] There are a wide variety of challenges that continue to surface.  One of the most important ones are features that require a custom design through changes to hardware and/or firmware.  A considerable amount of work and negotiations are required in working through the requirements, costs and time lines on everyone's part.  Although a challenge, it is an opportunity for companies such as Imperx, in this time when some of the larger manufacturers are pulling out of the custom market.

[Bill] For these two brands, the biggest hurdle is the lack of name recognition.  Also, integration with frame grabber manufacturers can be difficult as some companies are not open to building configuration files without the initial business to support the design work.  Even though high-technology industries are generally open to new products, brand recognition still plays a factor in choosing a camera.

[David C.] The challenge for DALSA lies in ensuring that we keep a balance between our commitment to developing new technology with the varied needs of our diverse machine vision customer base.  For example, customers inspecting flat panel displays may need the next generation in speed, while those performing web inspection require the next generation in resolution.

DALSA products incorporate the industry's latest imaging technology, advanced technology that customers may not be prepared for. We face a challenge today where our customers do not have technology available to them that can adequately acquire information at the speeds that our cameras are capable of.

[Steve/Gerhard] The most challenging aspect of offering our cameras to the machine vision world is the misconception that our cameras’ performance, resolution and dynamic range are too high, and in turn too expensive.  Unfortunately, this is wrong in many cases.  Although the cost of the our cameras are more expensive when compared to other component cameras used in machine vision systems, our cameras can substantially reduce the complexity of overall machine vision systems and bring about greater returns and economic efficiency to the application for the user.

Regrettably, most initial users take the path of perceived least expense, and fall into the trap of having to do much more work with the lighting, optics and software manipulation of the image to achieve their goal, if they obtain it at all.  In short, the ‘‘plug and play’‘ mentality soon becomes the ‘‘plug and slug’‘ reality.

[Jin/Dave] Machine vision cameras need to be tailored to the conditions that they will be used in.  Factors such as vibration and shock resistance become very important along with light sensitivity and spectral responses.  As cameras are progressing toward the digital world output formats and system control becomes a critical component. Other challenges include:

• Higher resolution, higher fps camera, and bigger pixel dimension at low cost.
• The limited interface that must support the customer’s current software.
• Delivery.

[Joachim] The main challenges are the price pressure, the expectations to get a reliable and calibrated product, easy of use/easy to integrate camera and last but not least customers requires a brilliant image quality with the condition of low power consumption and a small form factor.  Image quality is one of the main issues when selecting a digital camera for industrial purposes.  To deliver an image, e.g. with a CMOS sensor is easy, but to provide an excellent image quality, especially with higher frame rates is a real challenge.  Besides the reliability within industrial environment like EMI compatibility is a must-be-standard.  Industrial requirements are also shown in respect to the form factor of the housing, mounting holes, and connectors that have to be tightly mounted to the camera. 

The pricing of digital industrial cameras, like Basler offers, are often compared with consumer cameras.  Main focus of consumer still cameras is to increase the number of pixels, although the optical resolution is not achieved.  On the other hand, cameras for machine vision applications have to offer standard resolution with high frame rates and global shutter.  Therefore, costs of an industrial camera cannot be compared with consumer cameras.

[Christophe] There are many. As for us in ATMEL, I choose to mention: 

1. Small volumes of pieces: typically, the biggest OEMs consume thousands cameras/year; but, in most cases, the standard machine vision clients consume one or a few hundreds of units/year.

2. Various requirements: we cover a wide variety of applications, going in pair with various implementation modes.  Our choice in the design of AviivA families has been to propose a very versatile product, able to be operated at various data rates, timing mode, dynamic...and still, we deliver custom versions of these products to meet specific (sometimes exotic!) requirements.

3. Reluctance to changes: although the industry is moving fast, new solutions always appearing, we still face many clients whose main concern is to be delivered a stable product for 3 or even 5 years!

4. Reactivity: our clients work mainly by projects; they are often unable to provide forecasts but expect short lead times.  This is a constant challenge at the level of the supply chain.

5. Price pressure: although a camera is one component of (often big) a system, the pressure on price is permanent, and getting stronger this time, especially for companies based out of the Dollar area.

[Dave G.] Unfamiliarity with how to apply color imaging.  Unfamiliarity with how to apply line scan imaging.  Most vision integrators stick with VGA monochrome area cameras.

3. What are some challenging machine vision applications your cameras have addressed?
[John] CameraLink - color line scan applications GigE - High-resolution or medium frame rate applications that require the camera be located some distance from the processor.  The fact that a frame grabber is not needed here is also important to customers.

[Ilias] Sony’s industrial cameras are ideal for high-speed PCB inspection applications, small particle inspection and applications that subject cameras to extreme environmental conditions are at the top of our list.

[Keith] The most challenging have been: Flat Panel Inspection, contact lens inspection, print inspection, wafer inspection, and document scanning.

[Marty] Prosilica’s products are used in a wide range of machine vision applications.  A significant area is manufacturing quality assurance where speed and flexible triggering are a requirement.  The ability of our CV-Series cameras to daisy chain the trigger I/O with simple cables has made it a favorite for multi-camera applications.

Another application area that has been uniquely addressed by Prosilica cameras is automotive crash testing.  The very long cable length (up to 500 meters) offered by the fiber-optic output of our CV1280F and CV640F cameras have enabled bird’s-eye views of crash test sites while providing full camera controls.

Wood processing also presents some challenges.  We have customers who are imaging logs and lumber where the near-IR sensitivity of our CV640 cameras has enabled them to easily differentiate blue-stain defects in lumber and logs for grading and milling purposes.

Our new EC-series cameras have found application in semiconductor imaging where their ultra-compact size and light weight are of high value.

[Gunnar] High-performance metrology applications are extremely challenging.  In these cases, sub-pixel interpolation providing accuracy below 1/10 of a pixel requires cameras with very low noise and high MTF.  At the same time, the cameras must be moderately priced, as the systems are now also being used in production lines, and not only in the research labs.

[Loren] Imperx is a young company in the camera industry and many of the applications that we have addressed are still in the design stage so I am limited in what we can discuss.  One that I can discuss involved the scanning of old negatives.  The image needed to be inverted in real time and then a nonlinear correction applied.  The application required that this be done in real time on the camera.  The process of applying the image corrections, prompted the engineers to implement a more open architecture on the LYNX cameras. Custom LUT's can be created and uploaded to the camera by the user.

[Bill] For CIS, offering a CameraLink solution in a small package (29mm squared) and UXGA formats in color or monochrome at 30fps or higher.  We are finding electronics and PCB inspection equipment manufacturers interested in the UXGA units as the camera footprints are the smallest available in the market.  For NED, we are working on some different lumber applications in which monochrome systems are being upgraded to color to increase the robustness of the application.

[David C.] Medical imaging requires the clearest images for a finite level of detail that affects critical decisions made by medical personnel.  Our foundry’s low noise sensor process currently leads the world in noise performance.  This low noise process is leveraged in our sensors producing cameras with the lowest noise for the most detail.  An example is DALSA’s Pantera TF 11M4, which easily meets the demands of the bio-medical field with 11 megapixel resolution and 14 bit output for maximum detail detection at four frames per second.

Flat panel display inspection and printed circuit board inspection require the latest generation in speed and resolution.  These systems are inspecting for defects under 10-microns in size at incredible speeds.  The lighting that is required to keep up with the high speeds that these companies are running their systems becomes a huge challenge and a huge cost.  To overcome this challenge, DALSA offers large resolution TDI (time delay and integration) technology in cameras such as the Piranha HS 8K, which potentially achieves up to 640MHz throughput in low light conditions.  Designed to function optimally in low light conditions, our TDI technology allows customers to maintain the speeds of their systems without incurring the huge costs of extra lighting.

[Steve/Gerhard] The most challenging machine vision applications involve quality control demonstrating a high dynamic range or put in simpler terms, a wide variation of light levels.  A typical example is found in a bottle inspection machine.  In this case, it’s not known in advance if the glass bottle material is transparent or dyed, or if the bottles are very clean.  Additionally, such an operation will involve a large variety of bottle shapes.  All these factors produce a very wide range of light levels during the machine vision application.

To maintain high throughput on the production line, it’s usually not favorable to first measure the glass bottles and subsequently adjust the illumination, as is typically done in most machine vision applications.  It’s much better to incorporate a higher dynamic performance on the image capture and use an average illumination.  This approach provides much more information within the image because of the higher dynamic range of the camera, over the common approach.  Instead of a complex and time consuming light measuring and illumination control set-up, it's simply a 12-bit camera and a constant illumination, which enables a sufficient throughput.

[Jin/Dave] We have built cameras for a wide variety of situations.  Probably the most difficult was to build a single camera with multiple vision sensors that are then integrated into a single output.  Other challenging applications included:

• Fiducial reading with very little working distance in an existing machine.
• Reading low contrast, large area LCD Displays.
• Solving reflection & working distance issues.

[Joachim] One example is document scanning, which is usually done with line scan cameras.  The general trend is to extend to color images.  Basler has introduced a tri-linear camera to the market that does not use the prism 3CCD technology.  If some alignment conditions are fulfilled, a tri linear line scan camera provides excellent image quality with compact form factor and good price performance ratio.

Another challenging application is the field material testing that requires high frame rate and a good resolution.  To achieve these high data rates of more than 600 MB/s (equals one CD per second), special electronics inside the camera, cables, and frame grabbers have to be implemented.  The Basler A500 series has been developed for this kind of high-speed applications.

[Christophe] I would say:

• Web inspection and the challenge of aligning many cameras side by side, answered by ATMEL via the excellent positioning tolerance of the sensor inside a very compact camera housing.
• Packaging inspection (especially glass) where the main challenge is the antiblooming and the behavior for black/white transitions; the camera sees both the light source (very bright) and the bottle (very dark)
• Flat panel display inspection and PCB inspection, with the challenges of speed (addressed today with products featuring 160 MHz, higher in the future) and dynamic range to detect very tiny grey level variations differences (achieved thanks to the excellent signal to noise ratio performance of Atmel sensors)... going in pair with the sensitivity of the sensor. 

[Dave G.] Color uniformity measurement.  Wide-web textile inspection where there is no room for line scan cameras.

<