Basic guidelines in selecting a machine vision camera interface

Machine Vision InterfacesIndustrial machine vision camera interfaces have continued to develop allowing cameras to transfer megapixel images at extremely high frame rates.  These advancements are opening up endless applications, however each interface has its own pro’s and con’s.

 

Selecting the best digital camera interface can be done by taking in several considerations first and in doing so, can window down your selection.

The following are some considerations in making an interface selection.

  1. Bandwidth (Resolution and frame rate)
  2. Cable Length
  3. Cost
  4. Complexity

Bandwidth:  This is one of the biggest factors in selecting an interface as it essentially is the size of the pipe to allow data to flow.  Bandwidth can be calculated by resolution x frame rate x bit depth.   You essentially find out pixels / second x the frame bit depth resulting in your total Megabits / second (Mb/sec).  Large frame sizes at high speeds will require a large data pipe!  If not, you’ll be bandwidth limited, so one would need to reduce the frame rate and image size or a combination of both.

Cable Length:  The application will dictate the distance between the camera and industrial computer.  In factory automation applications, the cameras can be located in most cases within meters from the computer vs a stadium sports analytics application requiring 100’s of meters.

Cost:  Budgets dictate in most cases, so this must also be considered.  Interfaces such as USB are very low cost versus a CoaxPress interface which will require a $2K frame grabber and more expensive cables.

Complexity:  Not all interfaces are plug and play and require more complex configuration.  If you are leaning towards interfaces using frame grabbers and have no vision experience, you may want to elect using a certified systems integrator.

The considerations above will start to dictate the interface for the machine vision application.  The chart below provides an overview to help in the selection process.  machine vision interface chartFor a PDF of this chart, please email jonc@1stvision with subject “Interface chart”

Digital machine vision camera interfaces.

The interfaces each have pro’s and con’s aside from the designated bandwidth, cable lengths and costs, and outlined as follows:

USB2.0 is an older standard for machine vision cameras and now superseded by USB3.0 / 3.1 .  Early on, this was popular allowing cameras to easily plug and play with standard USB ports.  This is still a great option for lower frame rate applications and comes with low cost.  Click here for USB2 cameras.

USB3.0 / 3.1  is the next revision of USB2.0 allowing high data rates, plug and play capabilities and is ratified by the AIA standards, being “USB3 Vision” compliant.  This allows plug and play with 3rd party software following the GENICAM standards.  Cables lengths are limited to 5 meters, but can be overcome with active and optical cables.   Click here for USB3 cameras

GigE Vision was introduced in 2006 and is a widely accepted standard following GENICAM standards.  This is a the most popular high bandwidth interface allowing plug and play capabilities and allowing long cable lengths.  Power Over Ethernet (PoE) will allow 1 cable to be used for data and power making a simpler installation.  GigE is still not was fast as USB3.0, but has benefits of 100 meter cable lengths.  Click here for GigE cameras.

5 GiGe (aka N-base T) & 10GigE similar to USB2 moving to USB3, is the next iteration of the GigEVision standard providing more bandwidth.   Both follow the same GigE Vision standards, but now at higher bandwidths.  Specific NIC cards will be required to handle the interface.  Click here for 5 GigE cameras. 

CoaxPress (CXP) is a relatively new standard released in 2010, supported by GENICAM, utilizing coax cable to transmit data, trigger signals and power using one cable..  It is a scaleable interface via additional coax cables supporting up to 25Gb/s (3125MB/s) and higher now with CXP12.  The interface can support extremely high bandwidth as seen in the above chart with long cable lengths to 100+ meters depending on the configuration.  This interface requires a frame grabber which adds cost and some complexity in the overall setup.  Click here for CoaxPress cameras

Camera link is a well established standard, dedicated machine vision standard released in 2000 allowing high speed communications between cameras and frame grabbers.  It includes provisions for data, communications, camera timing and real time signaling to the camera.  A frame grabber is required similar to CXP adding cost and some complexity and is limited in cable lengths to 10 meters.  Longer cable lengths can be achieved with active and fiber optic cable solutions which additionally add cost.   Click here for CameraLink cameras

CameraLink HS is a dedicated machine vision standard taking key aspects of CameraLink and expanding upon it with more features.  This is a scaleable high speed interface with reliable data transfer and long cable lengths up to 300+ meters with low cost fiber connections.  Similar to CXP and camera link a frame grabber is required adding cost.  Click here for Cameralink HS cameras

Some caveats:  In calculating bandwidth, you can calculate the theoretical data rate, but in some interfaces, the real world practical will be different.  In Camera link and CoaxPress, the theoretical and practical are the same.   In Cameralink HS, limits will be set by the computer interface (i.e PCIe x 8, Gen 3 is 6.8 Gigabyte / sec and an Xtium CHLS frame grabber can capture 7 Gigabyte / sec!)

The theoretical and practical limits for USB and Ethernet can be quite different and there will always be some difference.  For example, large frames and low frame rate generates less interrupts, providing less overhead to the CPU.   A small frame with high frame rate generates more interrupts causing more load to the CPU.

Click to contact As a note:  This blog post covers the basics of each of the interfaces.  There is much more information 1stVision can share with you to be sure you are taking all aspects of the vision application into consideration.  We have several additional resources we can share to help, so don’t hesitate to contact us for free consultation!

1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera selection.  With a large portfolio of lenses, cables, NIC card and industrial computers, we can provide a full vision solution!

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Learn about the new 5GigE camera interface

Dalsa Nano 5GigE

Machine vision interfaces have continued to evolve over the years increasing data throughput and cable lengths.  Commonly used interfaces are GigE and USB3.  However, 5GigE is an interface now gaining attention in the industrial imaging / machine vision market with some nice advantages.

We will outline the benefits of 5GigE, but first, lets give a brief overview of the commonly used camera interfaces, with their pluses and minuses:

GigE  / GigE Vision

  • 110 MB/s of sustainable throughput.  In real world terms, a HD, 2MP camera can get 50-55 fps in 8 bit mono or 8 bit color mode.  Note, this isn’t real HD, since you need 60 FPS.
  • Data cable lengths up to 100m using regular CAT 5e/6 cable.
  • Easy to put multiple cameras on a system.

USB 3 / USB3 Vision

  • 420 MB/s of data throughput.    A HD 2MP camera can run 60 fps in 8 bit mono or color and can  also run RGB at 60 FPS no problem.  With the higher throughput,  a 5MP camera can achieve 85 fps in 8 bit mode.
  • Data cables up to 5 meters and up to 20 meters with active cables. However, active cables can be quite costly, adding up to $200 in cost.
  • Not as easy as GigE to put multiple cameras on a system, and gets harder with each additional camera, especially if you have limited USB3 controllers.

As a note, there is no cost difference when using cameras with the same sensor from the same manufacturer with USB or GigE!  They will cost about the same with no premium for one interface over the other.

gige nano 5gigeWhat are the limitations of GigE and USB3 now solved by 5GigE?

  • USB3 is limited in cable length, so going faster than GigE is great, but you can not have long cable lengths.
  • GigE has cable lengths up to 100 meters, but is limited to ~ 110MB/s of data, so you do not have the high frame rates as in a USB3 camera.
  • USB3 in 4+ camera systems is not as stable as GigE AND you’re still limited on cable lengths.

Wait! – What about 10GigE? 

Up until now, 10G was the next interface. However, the jump to 10G has quite a few limitations as outlined below.

  • Heat generation is significant, so cameras are large and not in the smaller 29 x 29mm cube form factor.
  • Not a lot of demand for very high speed 10G, so not a lot of sensors being offered
  • Minimal number of manufacturers for 10G, higher cost.
  • Special cabling, either optical or high quality cat 7.

What we have found is that there are several types of applications for 10G cameras and are as follows

  • Applications where you need 10G of speed of course (high resolution + fast frame rates)
  • Require greater than  110MB/s of data and need long cable lengths.
  • Where there is the required combination of 110MB/s for high frame rates, multiple cameras and long cable lengths, 10G is a perfect solution.

We have seen that the need for higher bandwidth + long cable lengths is more prominent vs. the real need for 10GigE!

 Introducing 5GigE that provides increased bandwidth, long cable lengths at reasonable prices! or N Base T.5GigE machine vision applications

5GigE (also known as N Base T) has become a new standard for industrial, machine vision cameras.

In the general compute world, a much much larger market than vision, there has also been a need to go faster than GigE. However, the issue of replacing the existing cabling is the major issue preventing this. If you think of a big box store, say a Home Depot for instance, the amount of cabling is huge. Ripping that out and rewiring far exceeds the cost of the equipment to use it!

5G was made to go faster, but use existing cabling. Regular cat6e cable can be used, and 5G is a subset of 10G, so all switches etc. can be kept in service.

5G gives users in the vision market USB3 speeds, but with ALL of the regular GigE features, at a very small premium!

get quote1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera selection.  With a large portfolio of lenses, cables, NIC card and industrial computers, we can provide a full vision solution!

 

What is a “TECless” SWIR camera? Learn more about Allied Vision’s highly cost-effective SWIR camera models

SWIR camera

Allied Vision Goldeye SWIR cameraShort Wave Infra-Red (SWIR) imaging is now more economical with the introduction of Allied Vision’s TECless Goldeye cameras.  SWIR cameras open up numerous application possibilities for machine vision solutions, since they are able to detect defects that are not visible to the naked eye.

SWIR cameras have an InGaAs (Indium Gallium Arsenide) sensor that detects wavelengths between 900nm and 1,700nm.  These wavelengths are invisible to the human eye and CCD / CMOS cameras, however SWIR cameras detect the invisible wavelength found in various applications.  For example water accumulations inside fruits or defects within silicon products.

SWIR - light emmission at 1150nm
Light emitted by silicon in solar cells peak at 1150nm

Learn more about applications solved with SWIR cameras HERE. 

SWIR cameras typically require Thermal Electric Coolers (TEC’s) which enable low-noise imaging in the spectral range of 900mm to 1,700nm.  Additionally, the TEC’s compensate for high temperature fluctuations and stabilizes the image sensor.
For temperature stable environments, Allied Vision now has a “TECless” InGaAs camera providing a lower entry price point, in turn an excellent price-performance ratio.
The Goldeye G-033 and CL-033 TECless InGaAs cameras are the solution to applications unachievable with standard cameras offering the following features
  • SWIR imaging from 900nm to 1700nm
  • High frame rates of 301 fps with VGA resolution
  • Power over Ethernet (PoE)
  • Compact design with no fan
  • Lower cost vs TEC versions
  • GigE and Camera link interfaces.

Click below for the full specifications on the Goldeye  TECless cameras and click “Get Quote” for pricing

GigE – Goldeye G-008 TECless
Camera link – Goldeye CL-008

Need to see it for yourself?  1stVision can provide a demo Goldeye camera to test on your application.  Submit your request for a demo camera by entering “Send me a demo SWIR camera” in the comment box.

Download the comprehensive SWIR application white paper here.  

1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera selection.  With a large portfolio of lenses, cables, NIC card and industrial computers, we can provide a full vision solution!

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How to select the best SWIR camera for my application and understand applications it can solve.

Download the comprehensive SWIR application white paper.

Learn about CoaXpress and frame rates achievable with Allied Vision’s “Bonito Pro” cameras with CXP-6

Allied Vision Bonito Pro camera

What is  CoaXPress, especially with “CXP-6” capability?

CoaXPress is an established industry standard allowing high speed communications over coaxial cable.  The current version supports bit rates up to 6.25 Gbits/sec over a single coaxial cable.  When used in parallel, two or more coaxial cables can provide incremental speed gains.  The naming convention associated with CoaXPress signify the bit rate as seen in the chart below.   In cases that you see CXP-6 has a bit rate of 6.25 Gb/s.  The 4 x means the number of lanes. Multiply the 2 and you get your total bit rate.

CXP CoaXpress

The new Allied Vision Bonito Pro cameras utilize 4 DIN 1.0/2.3 connectors on a CXP-6 interface (4 lanes) x 6.25Gbits/Sec. This  allows for resolutions of up to 26 megapixels to reach 70 frames per second (fps).  The first two Bonito PRO models (Bonito PRO X-2620 and X-1250) support high resolution with 26.6MP and 12.5MP at 80 and 142 fps respectively.

The Bonito PRO cameras are ideal for a wide range of applications including, 2D/ 3D surface inspection,  high speed printing, PCB & Electronics inspection.

Even faster frame rates can be achieved using the Bonito Pro X1250 (12.5MP) in partial scan mode.  Set to a 768 line height, a rate of 503 fps can be achieved!

Bonito Pro frame rates

The following video’s are good representations of what this relates to in real applications which you can appreciate.

Full specifications for the Allied Vision Bonito Pro cameras can be found HERE, but main features and benefits include:

  • Sensors available in Monochrome (X-1250B) and Color (X-1250C) and extended near-infrared (X1250B NIR ) models
  • On board defect pixel and 2D fixed pattern noise correction for improved image quality
  • Fan-less design for industrial imaging applications.
  • DIN 1.0 / 2.3 CoaXPress connections for secure operation in industrial environments.
  • Single cable solutions using trigger and power over CoaXPress (PoCXP)

contact us1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera selection.  With a large portfolio of lenses, cables, NIC card and industrial computers, we can provide a full vision solution!

 

UPDATE:  New video of the Bonito Pro detailing the multi-ROI function