The Wave WAA-1300-GE-TEC combines visible and short-wave infrared (SWIR) sensitivity in a single camera, enabling enhanced material contrast, improved defect detection, and more reliable inspection results. With sensitivity from 400 nm to 1700 nm, the camera can reveal features and material characteristics that may not be visible using standard imaging technologies.
Wave WAA-1300-GE-TEC SWIR camera – Courtesy JAI
Applications
Semiconductor alignment:
SWIR sees through silicon layers to find alignment marks. This enables precision through successive process layers. Image courtesy of JAI.
Fruit and vegetable sorting:
VIS + SWIR working together can identify bruising, ripeness levels, early spoilage, and more. Image courtesy of JAI.
Laser beam profiling:
SWIR enables measuring beam shape, intensity distribution, and alignment. Image courtesy of JAI.
Recycling and material sorting:
In VIS two clear plastic bottles might appear the same, but SWIR can see their different response in it’s portion of the spectrum – allowing different handling. SWIR enables measuring beam shape, intensity distribution, and alignment. Image courtesy of JAI.
Some of the key Wave WAA-1300-GE-TEC VIS SWIR features – Courtesy JAI
Utilize diverse spectral responses to your advantage
The application areas above are just representative, and are not meant to be exhaustive. The key point is that diverse materials provide differing spectral responses under appropriate light (including natural light).
Applications may be designed to identify and differentiate materials according to their spectral properties. Sensors, cameras, lighting, and lenses are available for machine vision applications that draw upon each of UV, VIS, IR, NIR, SWIR, MWIR, and LWIR portions of the spectrum. And combinations thereof – like the VisSWIR JAI Wave WAA-1300-GE-TEC.
About you: We want to hear from you! We’ve built our brand on our know-how and like to educate the marketplace on imaging technology topics… What would you like to hear about?… Drop a line to info@1stvision.com with what topics you’d like to know more about.
Short Wave Infrared (SWIR) imaging is enjoying double-digit growth rates, thanks to improving technologies and performance, and innovative applications. Unlike visible-light sensors, SWIR cameras can image through silicon, plastics, and other semitransparent materials. That’s really effective for many quality control applications, materials sorting and inspection, crop management, fruit sorting, medical applications, and more.
Visible vs. SWIR image pairs – Courtesy Allied Vision – a TKH Vision brand
Unlike CMOS sensors, from which high-quality images are reliably derived under wide operating conditions, SWIR sensors typically need “tuning” relative to temperature and exposure duration. First generation SWIR cameras sometimes generated images that while useful, were a bit rough and with certain limitations in the extreme. SWIR camera manufacturers have been innovating solutions to raise the performance of their cameras.
What’s the problem?
In short-wave infrared (SWIR) imaging applications, camera operation points such as exposure time, gain and bit-depth need to be adapted depending on the inspection task at hand. Image sensor defects such as defective pixels and image non-uniformities – inherent to SWIR sensors – are sensitive to the aforementioned operations points.
Unless controlled, image quality can suffer
Consider the following image:
The gray field is intentionally unexciting as a flat field baseline without a target. The white dots are undesired defect pixels, an unfortunate characteristic that one can thankfully correct through interpolation. This image is meant to show “what we do NOT want”.
The four parameters exposure setting, temperature, bit-depth, and gain may collectively be called the “Operating Point” of a SWIR sensor, as together they have a significant bearing on image quality. Through manual or automated adjustments, one can optimize image outcomes.
Harnessing variable parameters into manageable corrections – Courtesy Allied Vision – a TKH Vision brand
In this blog, we provide context for these concepts. And we introduce Dynamic Operating Point Optimization (DOPO) as an automated innovation available in the fx series of SWIR cameras offered by SVS Vistek / Allied Vision.
fx series SWIR cameras – Courtesy SVS Vistek / Allied Vision – a TKH Vision brand
Before Dynamic Operating Point Optimization (DOPO)
SWIR cameras with some image correction capabilities – prior to DOPO we’ll describe in the next section – certainly improved image quality. Largely via defect pixel correction (DPC) and non-uniformity correction (NUC).
Defect pixel correction (DPC) is achieved by replacing the “hot” or “dead” pixel value by the average value of its nearest neighbors. As long as there isn’t a cluster defect with multiple adjacent defect pixels (typically identified and rejected at manufacturing quality control), this is an effective solution.
Non-uniformity correction (NUC) is a bit more complex, but worth understanding. The non-uniformities arise in thermal imaging due to variations in sensitivity among pixels. If uncorrected, the target image could be negatively impacted with striations, ghost images, flecks, etc.
Factory configuration of each camera, before finalizing testing and shipping, adapts for the nuanced differences among individual sensors. Correction tables are created and stored onboard the camera, so that the user receives a camera that already compensates for the variations.
In reality it’s a bit more complicated
In fact defect pixels aren’t always simply hot or dead: they may appear only at certain operating points (exposure duration, temperature, gain, bit-depth, or combinations thereof).
Likewise for non-uniformity characteristics.
So that factory configuration mentioned above, while satisfactory for many applications, is a one size fits all best hope compromise, relative to the tools (then) available to the camera manufacturer and the price point the market would accept. Just as with t-shirts and socks, one size doesn’t really fit every need.
Dynamic Operating Point Optimization (DOPO)
Allied Vision has introduced dynamic operating point optimization (DOPO) to further automate SWIR cameras’ capacity to adapt to changes brought about by exposure time, temperature, gain, and bit depth. Let’s examine the graphic below to understand DOPO and the added value it delivers.
First consider the Y-axis, “Image Quality”. Looking at the flat-field gray block, clearly one would prefer the artifact-free characteristics of the upper region.
Also note the X-axis, “Sensor Temperature / Exposure Time”, for an uncooled thermal sensor. (Note that some thermal cameras do have sensor cooling options, but that’s a topic for another blog.) See the black line “No correction” sloping from upper left to lower right, and how the number of image artifacts grows markedly with exposure time. Without correction the defect pixels and sensor non-uniformities are very apparent.
Flat-field image quality with and without corrections – Courtesy Allied Vision – a TKH Vision brand
Now look at the gray lines labeled “NUC+DPC”. For a factory calibrated camera optimized for a sensor at 30 degrees Celsius and a 25ms exposure, the NUC and DPC corrections indeed optimize the image effectively – right at that particular operating point. And it’s “not bad” for exposure times of 20ms or 15ms to the left, or 30ms or 35ms to the right. But the corrections are less effective the further one gets away from that calibration point.
Finally let’s look at the zig-zag red lines labeled “DOPO”. Instead of the “one size best-guess” factory calibration, represented by the grey lines, a DOPO equipped camera is factory calibrated at up to 600 correction maps, varying each of exposure time, temperature, gain and bit depth across a range of steps, and building maps that represent all the stepwise permutations.
Takeaway: DOPO provides a set of correction tables not just one
So with DOPO providing a set of correction tables, the camera can automatically apply the best-fit correction for whatever operating point is in use. That’s the key point of DOPO. Unlike single-fit correction tables, with so many calibrated corrections under DOPO, the best-fit isn’t far off.
Give us some brief idea of your application and we will contact you to discuss camera options.
Thermal imaging with SWIR cameras – plenty of choices
There are a number of options as one selects a SWIR camera. Is your choice driven mostly by performance under extreme conditions? Size? Cost? A combination of these?
Call us at 978-474-0044. We can guide you to a best-fit solution, according to your requirements.
The key message of this blog is to introduce Dynamic Operating Point Optimization – DOPO – as a set of factory calibration tables and the camera’s ability to switch amongst them. An equally important takeaway is that you may or may not need DOPO for a particular thermal imaging application. There are many SWIR options, in cameras and lenses, and we can help you choose.
About you: We want to hear from you! We’ve built our brand on our know-how and like to educate the marketplace on imaging technology topics… What would you like to hear about?… Drop a line to info@1stvision.com with what topics you’d like to know more about.
While we humans can only see what we’ve named to be visible light, bees can see UV light! Some camera sensors register IR wavelengths! Some cameras can sense both visible light and on through NIR and SWIR.
In this piece we focus on applications that benefit from combined VIS-SWIR solutions, from 400 nm through 2.5 nm.
Deconstructing the electromagnetic spectrum into it’s commonly known constituent regions
Example applications
Just to whet the appetite, consider the 4 sets of image pairs below. In each case, the leftmost image was captured with visible wavelengths, while the righthand image utilized SWIR portions of the spectrum. These pairs were chosen to highlight the compelling power of SWIR to identify features that are not apparent in the visible portion of the spectrum.
VIS-SWIR image pairs – Courtesy Allied Vision – a TKH company
For certain applications, one wouldn’t need the human-visible images, of course, as with machine vision the whole point is to automate the image processing and corresponding actions. So for counterfeit banknote detection, bottle fill level monitoring, materials identification, or crop monitoring, one might just design for the SWIR portion of the spectrum and ignore the VIS.
Vein imaging application overlays SWIR image of veins into visible image of patient forearm –Image courtesy TAMRON
But some applications might benefit from both the VIS and the SWIR images. For example, the vein imaging application might require a VIS reference image as well as a SWIR-specific image, for patient education and/or medical records.
Monitor moisture levels in crops from airborne drone – Image courtesy TAMRON
For the crop monitoring application above, the VIS spectrum clearly orients trees, hills, buildings, and roadways. Meanwhile pseudo-color-mapping shows the varied moisture levels as sensed in the SWIR portion of the spectrum.
The range of potential applications combining VIS and SWIR is staggering. One can improved on one’s own or a competitor’s previous application. Or innovate something altogether new.
Sensors that register both VIS and SWIR wavelengths
Sony’s IMX992 and IMX993 sensors utilize Sony’s SenSWIR technology, such that a single sensor and camera may be deployed across the combined VIS and SWIR portions of the spectrum. Without such sensors, a VIS SWIR solution would require at least two separate cameras – one each for VIS and SWIR, respectively. That would add unnecessary expense, takes up more space, and require camera and image synchronization.
Now there are cameras, such as several in Allied Vision’s Alvium series, in which Sony’s SenSWIR sensors are embedded. With several interface options, including mipi, USB3 Vision, and 5GigE Vision:
Mipi, USB3 Vision, and 5GigE Vision interface options – Courtesy Allied Vision – a TKH Company
Lens manufacturers doing their part
One of the beauties of the free-market system, together with agreements on standards for interfaces and lens mounts, is that each innovator and manufacturer can focus on what he does best. Sensor manufacturers bring out new sensors. Camera designers embed those sensors and provide programming controls, communications interfaces, and lens mounts. And optics professionals design and produce lenses. The benefits from a range of choices, performance options, and price points.
Navitar VIS-SWIR lenses
Navitar’s ZOOM 7000-2 macro lens imaging system delivers superb optical performance and image quality for visible and SWIR imaging. Their robust design ensures reliability even in harsh environments. ZOOM 7000-2 macro lenses are ideal for applications, such as machine vision, scientific and medical imaging applications.
ZOOM 7000-2 VIS-SWIR lens – Courtesy Navitar
In fact there are three models in the series:
Each model has its application – but only the middle one is designed explicitly for VIS-SWIR – Courtesy Navitar
Kowa FC24M multispectral lenses
Kowa’s FC24M C-mount lens series are manufactured with wide-band multi-coating. That minimizes flare and ghosting from VIS through NIR. These lenses are also compelling for a number of other reasons, including wide working range (as close as 15 cm MOD), durable construction, and a unique close distance aberration compensation mechanism.
FC24M C-mount lens series – Courtesy Kowa
That “floating feature” creates stable optical performance at various working distances. Internal lens groups move independently of each other, which optimizes alignment compared to traditional lens design.
Tamron Wide-band SWIR lenses
Other lensing options include Tamron’s Wide-band SWIR lenses. While the name says SWIR, in fact they are VIS-SWIR. Designed for compatibility with Sony’s IMX990 and IMX991 SenSWIR sensors, you have even more lens choices. Call us at 978-474-0044 if you’d like us to help you navigate to best-fit components in cameras, lensing, and lighting, for your particular application.
About you: We want to hear from you! We’ve built our brand on our know-how and like to educate the marketplace on imaging technology topics… What would you like to hear about?… Drop a line to info@1stvision.com with what topics you’d like to know more about.
Available in 5.3 and 3.2 MP sensor options, the 5 GigE interface delivers framerates exceeding 100 fps. Based on the TEC-version of Sony’s IMX992/993 SenSWIR sensors, the cameras are sensitive from 400nm to 1,700nm, so they are classified as VSWIR. With a single sensor covering both the visible and SWIR range, new economies are possible for applications needing that spectral coverage.
Even if you don’t need VIS and just want SWIR…
These are compelling for SWIR applications for two key reasons:
They achieve impressive framerates for large sensors (by SWIR standards), at 115 fps for the 5.3 MP, and 159 fps for the 3.2 MP model. With a very affordable 5 GigE interface.
Outstanding image quality ideal for demanding applications.
Goldeye Pro – Courtesy Allied Vision – a TKH Vision brand
Our previous “coming soon” blog summarized key features, suggested applications, and a first look, so below we’ll go deeper now that the products are fully released.
Thermoelectric cooling (TEC) for image quality
The InGaAs (indium gallium arsenide) sensors used for SWIR imaging deliver the best images when temperature-stabilized. That’s provided by the thermoelectric cooling (TEC). That helps reduce dark noise and thermal current.
Must an InGaAs SWIR camera use TEC?
No, it’s not a requirement. Allied Vision is a leading producer of SWIR cameras, and while many include thermoelectric cooling, certain models do not. See all Allied Vision SWIR cameras and note some are “TECless.”
Whether your application requires TEC or not comes down to framerates, duty cycles, and overall performance demands. As with many engineering and design questions, how good is good enough?
Overview
Here are the key specifications at a glance:
Goldeye Pro models at a glance – Courtesy Allied Vision – a TKH Vision brand
Both provide digital binning and gain control to increase sensitivity.
And there are multiple user sets are available to simplify camera setup.
Applications
SWIR sees things that visible imaging cannot. (Likewise for UV, but that’s beyond the scope of this piece.) SWIR imaging can be mapped to “pseudo” images for human viewing – if required.
More to the point, machine vision applications get the job done in real-time without human involvement. Sort those materials. Monitor the perimeter for intruders. Optimize crop irrigation. etc.
If SWIR pseudo images help to get the juices flowing, here are a few:
Visible vs. SWIR image pairs – Courtesy Allied Vision – a TKH Vision brand
Vision Systems Design award-winner
While the award was earned in China, the cameras perform the same in whatever country they are deployed in.
About you: We want to hear from you! We’ve built our brand on our know-how and like to educate the marketplace on imaging technology topics… What would you like to hear about?… Drop a line to info@1stvision.com with what topics you’d like to know more about.
