Effective machine vision outcomes depend upon getting a good image. A well-chosen sensor and camera are a good start. So is a suitable lens. Just as important is lighting, since one needs photons coming from the object being imaged to pass through the lens and generate charges in the sensor, in order to create the digital image one can then process in software. Elsewhere we cover the full range of components to consider, but here we’ll focus on lighting.
While some applications are sufficiently well-lit without augmentation, many machine vision solutions are only achieved by using lighting matched to the sensor, lens, and object being imaged. This may be white light – which comes in various “temperatures”; but may also be red, blue, ultra-violet (UV), infra-red (IR), or hyper-spectral, for example.
LED bar lights are a particularly common choice, able to provide bright field or dark field illumination, according to how they are deployed. The illustrations below show several different scenarios.
Example uses of LED bar lights
LED light bars conventionally had to be factory assembled for specific customer requirements, and could not be re-configured in the field. The EFFI-Flex LED bar breaks free from many of those constraints. Available in various lengths, many features can be field-adapted by the user, including, for example:
Color of light emitted
Emitting angle
Optional polarizer
Built-in controller – continuous vs. strobed option
While the EFFI-Flex offers maximum configurability, sister products like the EFFI-Flex-CPT and EFFI-Flex-IP69K offer IP67 and IP69 protection, respectively, ideal for environments requiring more ruggedized or washdown components.
SWIR LED bar, backlight, and ringlight
Do you have an application you need tested with lights? Contact us and we can get your parts in the lab, test them and send images back. If your materials can’t be shipped because they are spoilable foodstuffs, hazmat items, or such, contact us anyway and we’ll figure out how to source the items or bring lights to your facility.
Test and optimize lighting with customer materials
Do I really need cables designed specifically for machine vision? As a distributor of machine vision cameras, lenses, camera systems, cables, and accessories, we hear this question many times a day. Why does your GigE or USB3 cable cost so much? I can just buy a cable online from Amazon, Ebay, etc. for $5 when yours costs $25 or more!
The answer is: You can… sometimes… but it depends upon many things, and how critical those things are to your application.
Here are 5 key variables you need to consider in a camera cable selection
Distance from camera to computer
Data rate in which the camera is transmitting
Importance of reliability of application
Structural integrity of connection at camera and computer
Total cost of your process and / or down time
From many years of diagnosing industrial imaging problems, especially after incorrect software setup, BAD CABLES ARE NEXT ON THE LIST FOR “MY CAMERA DOESN’T WORK” problems!! (Inadequate lighting or sub-optimal lensing also come up, but those are topics for another day.)
Distance, the killing factor! If you were to look at a “bode plot” of the signal transmitting from the camera to the computer you would see dramatic attenuation of the signal vs. distance, and also versus the data rate. In fact, at the distance limits, you might wonder if it actually works as the signal is so low!
GigE is rated at 100 meters, however, the signal does degrade quite a bit, so cable quality and data rate will be the determining factors. USB3 does not have a real specification and it is difficult to find consumer grade cables greater than 2 meters in length. In fact, we have experienced poor results with consumer cables greater than 1 meter in length!
What are the differences between ‘Industrial’ and ‘’consumer’ cables?
8 differences are listed below:
Assorted machine vision cables
Industrial cables are tested to a specification for each cable. There are no batch to batch differences.
That specification usually meets organization requirements such as IEEE or Automated Imaging Association (AIA) standards
Industrial cables give you consistency from a single manufacturer (when buying online, you are not always sure you are getting the same cable)
Industrial cables have over-molded connectors
Industrial cables have screw locks on the ends
Industrial cables are usually made with larger gauge wire
Industrial cables typically specify bend radius
Industrial cables are made with flex requirements (bend cycles they can meet)
When should we consider using an “Industrial cable”? Here are a few examples to consider:
Example 1: In a research lab, using a microscope 1 meter from the computer running low data rates, non automated.
Distance is small, data rate is low, chance of someone pulling on the cable is low, and if the data doesn’t get delivered, you can re-acquire the image. There is no big need for a special cable and can buy it off the internet.
Example 1a: Let’s change some of these parameters, now assuming you are not in lab, but the microscope is in an OEM instrument being shipped all over the world.
If the system fails because you went with an unspecified cable, what is the cost of sending someone to fix this system 3000 miles away? In this situation, even though the distance is small, and the data rate is low, the consequences of a cable failure are very high!
Example 2: GigE cameras running at close to the full bandwidth. If you don’t need screw lock connectors, and the distance is not too great (< 10 or 20 meters),
You can probably get by with ‘higher quality’ consumer cables. At distances greater than 20 meters, if you care about system reliability, you will definitely want industrial cables.
Example 3. Two to Four GigE cameras running at close to full bandwidth in a system.
If you need system repeatability, or anything close to determinism, you will need industrial cables. On the other hand, if you your application is not sensitive to packet re-sends, a consumer cable should work at under 20 meters
Example 4. GigE cameras in an instrument. Regular GigE cables are just locked into the RJ45 with a plastic tab.
If your product is being shipped, you can’t rely on this not to break. You want an industrial cable with screw locks.
Example 5. GigE cameras in a lab.
Save the money and use a consumer cable!
Key takeaways:
If you running USB3 cables at distances more than 2 meters, DO NOT use consumer cables.
If you are running multiple cameras at high speeds, DO NOT use consumer cables.
Obviously, if you need to make sure your cables stay connected, and need lock downs on the connectors, you cannot use consumer cables.
If you are running low speed , short distance, and you can afford to re-transmit your data, consumer cables might be just fine.
Below are additional remarks provided by our cable manufacturing partner Components Express Inc., that help to support the above conclusions. It’s good reading for those who want to understand the value-added processes used to produce specialized cables.
Families of connectors for vision systems include right-angle options to address commonly found space constraints and/or avoid overstressing the cable strain relief. Generic cables are typically “straight on” only.
The test process for machine vision cables go beyond routing hi-pot testing to include the electrical testing that ensures conformance with the latest and most stringent machine vision performance standards. Machine vision configurators – using customer application parameters – prevent mis-applying a cable that won’t meet the performance requirements.
Machine vision cable families cater to de-facto standards. For example, pin-outs vary by ring lighting makers for the same 5-pin connector. So it’s more labor and cost-intensive to support the permutations of pin-outs across diverse camera and lighting manufacturers.
The IP67 versions of standard electrical interfaces can vary by camera body. Machine vision cameras have different part numbers for specific camera bodies. For example, a screw lock Ethernet cable might damage the camera body of another maker if the mold-to-connector nose distance varies.
Machine vision y-cables are a unique breed and typically bought in small quantities. Pin-outs are higher and the semi-standard interfaces are different.
Some applications demand high resolution from 16MP or up to 151MP. Thanks to dual and 10GigE interfaces, Camera Link, and CoaXPress, getting image data from the camera to the computer can be accomplished at speeds matched to application requirements, using camera series HR and SHR from SVS-Vistek.
What kind of applications require such resolution? Detail-demanding manufacturing inspection, geo mapping, life science, film industry and other applications require, or benefit from, a high resolution image delivered from the camera directly to the PC. Prior to the convergence of high-resolution sensors and high-speed interfaces, one might have needed multiple smaller-resolution cameras to capture the entire field of view – but with complex optical alignment and image-stitching (in software) to piece together the desired image.
The HR series offers resolutions from 16 – 120MP. The SHR series ranges from 47 – 151MP. While every machine vision camera offers various features designed to enhance ease-of-use or applications outcomes, here are some particular features we highlight from one or both of the HR or SHR series:
Minimal 128 MB internal image memory, burst mode – capture sequences rapidly on the camera and transfer them to the computer before the next event
LED controller for continuous & strobe built into camera – avoids the need to purchase and integrate a separate controller
Programmable logic functions , sequencers and timers – critical for certain applications where programmed capture sequences can be pre-loaded on the camera
RS-232 serial data to control exposure, lights or lenses
Long exposure times up to 60 seconds (camera model dependent) – useful for low-light applications such as those sometimes found in life sciences or astrophysics
Camera Link, CoaXPress and 10GigE interface options (varies by model)
For pricing on the HR / HSR Series, follow the family links below to the series table, then click on “Get quote” for a specific model of interest. Or just call us at 978-474-0044 to discuss your application and let us guide you to the best fit.
The HR series uses a range of CCD and CMOS sensors from CANON, Sony and ON Semi. The SDR series use both CCDs from ON Semi and CMOS sensors from Sony. The same sensor choices and feature sets are offered across several popular machine vision interfaces, permitting users to tailor their own need for speed to specific application requirements. SVS-VISTEK engineering and manufacturing precision mounts these high-resolution sensors, which allows users to have distortion free, high quality, high content images.
SVS-Vistek shr661 – 127 megapixel camera
At the time of writing, note the newest member of the SHR series, the shr661. At 127 megapixels this CMOS sensor camera has remarkably high resolution with a global shutter. With the IMX661 sensor from the Sony Pregius series, the backlight technology enables very high light sensitivity and above-average noise behavior. This enables an image quality with which even the finest structures can be resolved. The shr661 is one of the most powerful industrial cameras on the market.
Those familiar with high-resolution sensors may know about dual and quad-tap sensors, whereby higher frame rates may be achieved with electronics permitting two or more sections of the sensor’s pixel values to be read out in parallel. A traditional challenge to that approach has been for camera manufacturers to match or balance the taps so that no discernable boundary line is visible in the composite stitched image. SVS-Vistek is an industry leader with their proprietary algorithm for multi-tap image stitching.
The Computar MPT Series is a compact 45MP, 1.4″ C-Mount Lens Series engineered to optimize the capabilities of the latest industrial CMOS sensors. The 1.4″ Ultra-high resolution Machine Vision Lenses are ultra-low distortion in a compact design available in fixed focal lengths: 12mm, 16mm, 25mm, 35mm, and 50mm. C-Mount for large format sensor.
Computar MPT 45MP C-Mount series
Designed for up to 1.4″ sensors with densely-packed pixels, as compact C-Mount lenses one achieves a more compact overall design, and lower optics costs than with a large-format lens, at the same time getting high performance. High-level aberration correction and centering/alignment technology deliver an extraordinary performance from the image center to the corner with tiny pixels.
Since the lenses may also be used with popular 1.2″ sensors, one achieves impressive Modular Transfer Function (MTF) outcomes in such a configuration.
Screenshot from video below highlights MTF performance across working distances
Call us at 978-474-0044 for expert assistance. We can tell you more about these lenses, and help you determine if they are best for your application.
The Computar MPT series lenses deliver superior performance at any working distance, thanks to the floating design. This is ideal for industrial drones, sports analytics, wide-area surveillance, and other vertical markets.
Vision Systems Design awarded the Silver Honoree in their Innovator Awards for the Computar MPT lens series.
