Opto Engineering is known and respected for high-performance lenses in machine vision, medical, and related fields. The new TCSE series are telecentric lenses designed for large sensor formats (4/3″, APS-C, APS-H). Each provides high resolution with low distortion.
Who needs a telecentric lens?
Before inviting you to some of the TCSE series features, let’s offer readers who aren’t already telecentric-savvy a brief motivation for this category of lens. If you are doing precise gauging applications – measuring via optics and software – your tolerances may require a telecentric lens. A telecentric lens eliminates perspective error. They have very low distortion. And, if paired with collimated light, they enhance edge definition.
For a comprehensive read, check out our blog Advantages of Telecentric Lenses in Machine Vision Applications. Not sure if you need a telecentric lens? Call us at 978-474-0044 – tell us a little about your application and we can guide you through any or all of lens, camera, lighting and other choices.
TCSE lenses are available for applications using light in either the visible spectrum or near-infrared (NIR) wavelengths. Currently there are 8 members in the TCSE product family.
Image circle diameter
The TCSE Series offers image circle diameter options from 24 – 45mm.
Magnification
A key parameter in telecentric imaging is the level of magnification available. The 8 members of the TCSE Series offer magnification ranging from 0.36 through 2.75 times the original object size.
Working distance
The working distance (WD), from the front of the lens to the object being imaged, varies by lens model across the TCSE Series. The shortest WD offered is 160mm, spanning distances up to 240mm. These long working distances allow space for lighting and/or robotic arms.
Worth noting
While typically “plug and play” once mounted on your camera, it’s worth noting that the TCSE lenses offer back focal length adjustment, should one choose to fine tune.
Summary
Telecentric lenses are the core business for Opto Engineering, who have more than 20 years expertise in research, development, and production. 1stVision, North America’s largest stocking distributor, works to understand each customer’s application requirements, to help you select the ideal lens, camera, or other imaging component(s). Call us at 978-474-0044.
Teledyne DALSA has released the AxCIS 800mm mono/HDR, and the AxCIS 400mm mono, the first two members of a new flexible and scalable product family of Contact Image Sensors (CIS). As other members are released, users can choose fields of view (FoV) in 100mm increments, e.g. 400mm, 500mm, 600mm, 700mm, and 800mm.
Contact Image Sensor vs. Linescan
Actually that’s a trick heading! A contact image sensor (CIS) is a type of linescan camera. Conventionally, the industry calls it a linescan camera if the sensor uses CMOS or CCD. while it’s called a CIS if it bundles a linear array of detectors, lenses, and lights.
But CIS is very much a linescan type of camera, With a 2D area scan camera, a comprehensive pixel array captures hundreds or thousands of (X,Y) values in a single exposure. But a Contact Image Sensor requires either the target or the imaging unit to move, as a single exposure is a slice of Y values at a given coordinate X. Motion is required to step across the set of X values.
Two more notes:
The set of X values may be effectively infinite, as with “web inspection” applications
The term “contact” in CIS is a bit of a misnomer. The sensor array is in fact “very close” to the surface, which must thereby be essentially flat in order to sustain collision-free motion. But it doesn’t actually touch.
AxCIS key attributes include:
28um pixel size (900dpi)
high speed 120KHz using Camera Link HS
HDR imaging with dual exposure mode
optional LED lighting
fiberoptic cables immune to EMI radiation
Application areas share the characteristics of flat surfaces and motion of either the target or the sensor, since contact image sensing (CIS) is a form of linescan imaging.
HDR imaging
Some targets are inherently challenging to obtain sufficient saturation for the darker regions while avoiding over-saturation for the lighter areas. The multiline sensors used in AxCIS utilize a sensor array with:
One row of the sensor array that can have a longer exposure for dark scenes
Another row using a shorter exposure for light scenes
The camera then combines the images, as shown below. The technique is referred to as High Dynamic Range imaging – HDR.
Want to know more about area scan vs line scan? And multifield line scan? And other Teledyne DALSA linescan products, in which they have years of expertise? See our blog “What can multifield linescan imaging do for me?“.
For details on the AxCIS CIS family, please see the product page with detailed specs.
If you’ve had enough reading, and want to speak with a real live engineer, just call us at 978-474-0044.
While a standard lens is adequate or even ideal for many machine vision applications, there is inherent distortion in a standard lens, often in the range of 1 – 2%. Telecentric lenses achieve distortion of 0.1% or less. They also provide constant magnification and no perspective error.
If you “just” need presence/absence detection, or counting discreet non-occluded objects, a conventional lens may be fine. But if you need highly accurate contactless measurement, telecentric lenses offer remarkable performance.
Let’s take a brief look at what qualifies a lens as telecentric, and why you might want (or need) one. Subsequently we’ll summarize Edmund Optics SilverTLTM and CobaltTLTM lens series.
Telecentric Tutorial
Telecentric lenses only accept incoming light rays that are parallel to the optical axis of the lens. It’s not that the oblique rays don’t reach the outer edge of the telecentric lens. Rather, it’s about the optical design of the lens in terms of what it passes on through the other lens elements and onto the sensor focal plane.
Hmm, but the telecentric lens must have a narrower Field of View (FoV) – and I have to pay a premium for that? Well yes – and yes. There are certain benefits.
Let’s get to an example. In the image immediately below, labeled “Setup”, we see a pair of cubes positioned with one forward of the other. This image was made with a conventional (entocentric) lens, whereby all three dimensions appear much the same as for human vision. It looks natural to us because that’s what we’re used to. And if we just wanted to count how many orange cubes are present, the lens used to make the setup image is probably good enough.
But suppose we want to measure the X and Y dimensions of the cubes, to see if they are within rigorous tolerance limits?
An object-space telecentric lens focuses the light without the perspective of distance. Below, the image on the left is the “straight on” view of the same cubes positioned as in “Setup” above, taken with a conventional lens. The forward cube appears larger, when in fact we know it to be exactly the same size.
The rightmost image below was made with a telecentric lens, which effectively collapses the Z dimension, while preserving X and Y. If measuring X and Y is your goal, without regard to Z, a telecentric lens may be what you need.
Depth of Field can be “pushed”
You are likely familiar with Depth of Field (DoF), the range in the Z dimension in which objects in the FoV are in focus. With a conventional lens, if an object moves out of focus, the induced blur is asymmetrical, due to parallax (aka. perspective error).
But with a telecentric lens, there is no parallax error, since the FoV is constant and non-angular. A benefit of this is that even if the target image is somewhat defocused with a telecentric lens, the image may still be perfectly usable.
In the two images below, the “sharp transition” edge is clearly optimal. But when measuring tolerances in a manufacturing environment, with mechanized conveyors, vibration, etc., target objects may not always be ideally positioned. So the “shallow transition” image from the object just out of focus is entirely acceptable to identify the center of mass for the circular object, since the transition is symmetrical at all positions.
Edmund Optics is widely recognized for their range of standard products – and their expertise in custom lens design when needed. The SilverTLTM and CobaltTLTM lens series each offer 10+ members, where all lenses are high-resolution and bi-telectric. Some additionally offer inline illumination options.
Noteworthy characteristics of both the SilverTL and CobaltTL series include:
Aperture controls often not available in competitor products
“Fast” ==> lower F# options than in many competitor products (so can work effectively with less light)
Conform to narrowly specified engineering tolerances
Pricing identical with or without in-line illumination via coax port
Edmund Optics SilverTLTM series
The SilverTL series pairs with C-mount sensors up to 7.5 MegaPixels, ideal with 2.8 µm pixel size. Magnification options range from 0.16X to 4X.
Edmund Optics CobaltTLTM series
For C-mount sensors up to 20 MegaPixels, and pixel size 2.2 µm, choose the CobaltTL series.
What type of lens is best for my application?
Machine vision is a broad field, with a lot of variables across wavelengths, application goals, sensor, software, and lens choices. If you are a seasoned veteran, you may know from experience exactly what you need. Or you may want to review our on-line knowledge base or online blogs. Easier yet – just phone us at 978-474-0044. You’ll speak with one of our sales engineers, who put customer success first. Customers with successful outcomes – who return to us project after project – is our goal.
IDS Imaging will soon release new members in their uEye+ camera series, utilizing Sony’s 4th generation Pregius S sensors. Included are 16, 20, and 24 MP offerings of the compact uEye+ USB3 cameras.
The “S” in Pregius S stands for “stacked”, a sensor architecture that is back-illuminated as well as layered, creating a light-sensitive, low-noise, high-performance sensor. Even the first 3 generations of Sony Pregius sensors broke new ground, but Pregius S is special. Read our dedicated blog on the Sony Pregius four generation offerings, including details on Pregius S.
Sony Pregius S sensor
MP
Format
IMX 532
16
5328 x 3040
IMX 531
20
4512 x 4512
IMX 530
24
5328 x 4608
Sony Pregius S sensors joining IDS uEye+ family
IDS peak SDK : “Configuring instead of programming”
Enhancing the ease of development and deployment for the uEye+ cameras, IDS has released update 2.6 of “IDS peak”, the comprehensive software development kit (SDK), available at no cost. Of course the cameras are Vision Standard compatible ( U3V and GenICam), for those preferring third party SDKs, but IDS peak has much to offer IDS’ camera users.
While the SDK naturally includes conventional programming interfaces, IDS includes tools such as tools such as histograms, line and pixel views, color and greyscale conversions, useful automatic functions and bandwidth management. These skew deployment helpfully towards “configuring instead of programming”.
IDS peak is available for both Windows and Linux OS. In addition, IDS peak SDK works not just with IDS USB3 cameras, but also IDS GigE cameras. So multi-camera applications with mixed interfaces are possible. Or your developers can benefit from familiarity with a single SDK across multiple applications, bringing efficiencies to your team. Download IDS SDKs here.
Call us at 978-474-0044. Tell us about your applications goals and constraints, and we can guide you to any or all of cameras, lenses, lighting, software, and accessories.