Newsflash: Machine Vision Camera-maker Thinks You Should Buy More Machine Vision Cameras!

This comes from Basler, who suggest it’s time to ditch Firewire/1394 for USB 3.0. A White Paper on their website sets out their reasoning, some of which makes sense and some of which I would question.

Four arguments are presented: 1394 hardware will disappear, Windows 8 doesn’t support it, the bandwidth is insufficient, and it will save you money.

The first two of these I agree with completely. Indeed, it’s been several years since I developed anything with Firewire, preferring to use GigE instead. So yes, new systems should not be developed with this outdated interface. But if the system is in-service and working well, why would you change?

The bandwidth argument makes no sense, and how will replacing cameras that still work save money?

Bottom line: if you’re developing applications with Firewire interfaces you’re building-in obsolescence. But if your old Firewire systems still perform the way you need, stay with them.

I suppose I should add one caveat: smart engineers will be looking ahead at how they would replace the old systems when they do fail.

Firewire and Windows 7

If you've been paying attention you'll have read about my troubles with Service Pack 3 of the venerable Windows XP operating system. At the end of the posting, I wondered allowed if Windows 7 would play nice with Firewire.

Well the very kind Oliver Günnel of Allied Vision Technologies, (www.alliedvisiontec.com ) sent me an answer.

“Yes,” he said, Window s7 works well with Firewire b (1394b for those who prefer the numbers,) but it's not so good with Firewire a. He went on tell me that information on this is available at the AVT website, under the heading of, “My FireWire camera is not recognized under Windows 7,”.

Don't say I never give you anything useful!

Firewire problems

Remember when XP Service Pack 2 came along and messed up your Firewire camera data transfer speed? This was so long ago that I’d forgotten it, until I couldn’t get a high-res color Firewire camera to serve up images at the required frame rate.

After some head-scratching I noticed I was only getting 100Mbps and something deep in my memory told me it should have been 400. Eventually I got on to Google, and there I learned that Service Pack 3 had the same problem. In fact, for some bizarre reason, if you had implemented the SP2-1394 fix, the upgrade to SP3 would revert back to 100Mbps.

Being knowledgeable machine vision types, you, my dear readers, probably know all this. But just in case you too have forgotten, here are a couple of links.

Here is some information about XP SP2 and its impact on 1394 data speed.

And to bring you up to date, here’s a link to the Microsoft Knowledgebase article about 1394 and XP SP3.

Suddenly I’m wondering what speed to expect with Windows 7. Anyone?

Camera trends

The love-fest that is Vision 2012 is less than a month away and already vendors are giving us sneak-peeks at their latest and greatest. Some of the most intriguing come from camera-maker AVT who, besides some ho-hum range extensions, have an entirely new product, the Mako.

As I write this, the Mako page on the AVT website doesn’t have any content, so instead I will direct you their press release. Now this camera looks much like the reliable old Guppy, but whereas that was a FireWire camera, this will be offered with both GigE and USB3 interfaces.

I see that as highly significant. In fact I’d go so far as to say it means FireWire is on its death-bed, at least in the machine vision world. Some years back AVT saw how the wind was blowing when they snapped up Prosilica, thereby gaining a GigE product line up, and now they’re backing the new USB standard. I’d say that means the future is GigE and USB3, for everything except really large sensor formats and very high data rates.

Just out of curiosity, does anyone think we’ll see a linescan USB3 camera before the year end?

Let’s hear it for FireWire

Last week I said that FireWire is “just falling by the wayside,” (“Mastering the GigE interface” September 6^th, 2012,) and then I read “Firewire Cameras: The Future of FireWire” on the Vision & Sensors website, which opens by asking, “Is FireWire dying?” Probably a coincidence, but who knows?

The article was written by Point Grey, takes a fairly pro-FireWire stance, and makes some good points. FireWire is a single cable system (power goes through the camera cable,) and it has some neat features like daisy-chaining. But I do disagree with the speed claims.

My issue is not that the info is inaccurate – it isn’t – but that the 800Mbit/sec rate assumes the use of FireWire b. Now I’ve always had a problem with this, because Windows doesn’t support this speed. Yes, I realize Point Grey provides ways around this, but it detracts from the essential easiness of FireWire.

Don’t misunderstand me, I like FireWire, but as the numbers in the article show, GigE is gaining ground. After all, some people still use analogue cameras but that doesn’t mean it’s where the future is. So bottom line – I stand by my contention that FireWire is “falling by the wayside.”

Another twist to camera interfaces

With various groups making plays for their preferred new standard – USB 3.0, CameraLink HS and CoaXPress – camera interfaces are in the news of late. Everyone talks about data rates and cable lengths - I’ve done my part, with “King of the (camera interface speed) hill” and “Everything you ever wanted to know about USB3.0” – but writing in the Adimec blog, Gretchen Alper offers another factor to consider: the cost of the cables. (“How to save cabling costs with new machine vision interfaces” August 29^th, 2012.)

Now I knew that CameraLink cables were expensive, but I hadn’t appreciated just how expensive in comparison to GigE, FireWire, USB 3.0 and CoaXPress. (Read Gretchen’s blog post to see the actual numbers.) CoaxPress is of course just plain old co-ax cable, which is why it’s so cheap. As backers of this new standard, Adimec aren’t exactly neutral, so I would expect them to have done their best to ‘spin’ the cable cost issue, but even so, the numbers are pretty startling.

I wonder if this might change your choice of interface next time you spec out a system?

King of the (camera interface speed) hill

Most of us were happy with FireWire-b and had no need of faster data rates. Then along came GigE and the bits flowed faster. If we needed real speed, like for those occasional linescan projects, there was always CameraLink.

But just as racing drivers always want more, so too do some machine vision people. Many of these are in the high speed web inspection niche, and they were starting to think that good old CameraLink might not be up to the job in a few years. So Dalsa started work on an interface they called “HSLink”.

This showed a lot of promise, but as Mike Miethig of Dalsa discusses in “Vision Market Touts Camera Link HS in Boston, Beyond” (Quality magazine, August 7^th, 2012,) it never really gained traction.

Fortunately for the speed freaks though, it did set the scene for CameraLink HS, which promises speeds of up to 2.1Gbytes/sec. Now that number might be hard to grasp, so I’ve put together a little graphic to show just how much faster than the older standards that is.

 

 

Now there are some important caveats. CameraLink speeds are complicated because they depend on whether it’s Base, Medium, or Full configuration. CameraLinkHS is much the same: there are three speed flavors, starting at a relatively paltry 300Mbytes/sec. And then, missing from my table, is CoaXpress.

CoaXpress boasts of up to 6.25Gbps, (which I suspect is gigabits rather than bytes,) so it’s not a s fast as CameraLink HS. More importantly, it’s not an AIA standard – it’s supported by the Japan Industrial Imaging Association – so whether it will prosper remains to be seen.

And what does this mean for the regular machine vision user? It means there’s virtually no limit to how fast you can shove those pixels down the pipe. The only question to consider is, how deep are your pockets?

Yet another camera communication standard

FireWire, GigE, USB 3.0 … do we need another standard? Well some machine vision users do, yes.

The problem is that every standard has its strengths and weaknesses. I touched on this last month under the heading of “Pros and Cons” (take a look for details,) so some users want something that does better – “better” usually meaning higher speeds over long cable lengths.

That’s where CameraLink High Speed (CLHS) comes in. Promoted by Teledyne Dalsa, this aims to be “future proof” so as you upgrade to ever higher resolution cameras the infrastructure can remain unchanged. Personally I think this is more of an issue in traffic and surveillance applications, but it’s something we industrial/manufacturing types should be aware of.

So how do you learn more? Well as always, you click the link I shall provide. In this case it takes you to “Vision & Sensors: Machine Vision Standards”, published on the Vision & Sensors site, March 8^th 2012.

Be aware though that CLHS may not be the last word in camera interfaces: there’s CoaXPress too.

Pros and Cons

“Mr. Grey,” the email began. Oh how I love that olde worlde formality. “I see some machine vision cameras now use the USB3.0 interface. Should I switch from 1394?”

If only I could offer a clear-cut yes or no answer, but unfortunately the world doesn’t work like that. Instead, I have to go with the standard integrator response of “It depends.”

USB3.0 has some attractive features for machine vision, most notably speed approaching that of CameraLink and power through the same cable, but in other regards it’s less than ideal. Cable length is limited, though you can add repeaters, and while it’s less of a CPU-hog than USB2.0 it’s still not as good as 1394b. A bigger concern in my view though is lack of Windows support. It’s my understanding we’ll have to wait for Windows 8 to take full advantage of the 3.0 ports now appearing on PC’s.

For those interested in learning more, there’s a great FAQ on the website of camera-maker Point Grey (no, we’re not related.) If you scroll through the Q’s you’ll eventually come to a table comparing the merits of the various interfaces (the latest high-speed systems have been omitted.) Now bearing in mind that Point Grey are in the 1394 and USB camera business, what surprised me is that 1394 still seems a good choice for run-of-the-mill applications where the speed demands aren’t extreme. On the other hand, while USB3.0 seems not to excel at anything, it clearly has the potential to be a good choice overall.

So to answer my email friend’s question – should you switch from 1394 to USB3.0? Right now I would say no, unless you want to be at the cutting edge. Personally, I’ve been cut enough over the years, so I’m going to hang back and let others iron out the bugs. But ask me again in twelve months and I may have a different answer.

USB3 fit for machine vision?

USB cameras have never really been adopted for machine vision. Yes there are some products on the market – Lumenera seems to be leading the pack – but they’ve failed to break through. As I understand it, this is mainly due to the way USB tends to hog more CPU time than does FireWire or GigE, and because it’s difficult to have more than a single camera per PC.

Things seem different with USB3. This interface seems to be building a head of steam with vendors such as Point Grey, Ximea, and Basler all launching USB3 cameras.

What does that mean for we end-users? I think it means life just got a little more complicated. There I was, getting to grips with GigE, learning how to address the cameras (not as easy as the vendors would have you believe,) and now they expect me to try something else. And what does USB3 give that GigE doesn’t?

I’m not sure I know. Speeds are broadly comparable and cable lengths are plenty long enough for my industrial needs. One difference might be that USB3 supplies power, so I can save on a separate power supply. Yes, I could go PoE but that doesn’t really seem to have broken through, so camera choices are limited.

I don’t know about you, but I think I’ll hang back and watch how this all pans out.

New cameras

Over the last few days there’s been a torrent of new product announcements from German camera manufacturer AVT. Might this be connected with the Vision show held last week? How naive do you think I am?

Cynicism aside, these are some interesting products. Let’s start with the 6 Mp Prosilica GX2750. This uses a Dual GigE Vision® interface to deliver full-frame images from its CCD sensor at 19fps. Impressive numbers, to be sure. I have to say though, since I believe the pixels are just 4.5 microns and the cooling fins imply considerable heat generation, I am a little concerned about noise in the images.

Perhaps then I should look at their cooled camera, the AVT Bigeye with Active Cooling. Presumably resulting from the acquisition of VDS, this features a Peltier cooler to reduce noise. I have a feeling this is something we shall see more of as pixels shrink and resolutions grow.

Last off, (and I lack a good segue into this,) is the AVT Bonito. This is an impressively fast camera – 4Mp at 386fps – but what really intrigues me is the interface: CameraLink.

Okay, there’s nothing particularly earth shattering about CameraLink, but it’s new for AVT. They started out with FireWire, moving into GigE with the acquisition of Prosilica. And now CameraLink?

If other camera companies weren’t already paying close attention to AVT before, they should be now.

Trends in machine vision cameras

CameraLink provides the highest robustness and data rates, FireWire has been superseded by GigE, and USB is irrelevant for machine vision. Oh, and by the way, resolutions are going up.

Well that’s what I told an engineer who emailed me a few days ago asking if he should stick with FireWire cameras, but let’s take a moment to dive deeper.

Few in machine vision would argue that CameraLink, for now at least, provides the best overall performance. It can handle the highest data rates, (up to 6Gbps with 2 cables,) works over cable lengths as long as 10 meters, (enough for most industrial applications,) and never misses a frame, but it does have downsides. Chief among these is cost. CameraLink needs a framegrabber, which can easily cost $500 or more. It also needs special or custom cables – yet more cost. And since Power-Over-CameraLink (PoCL) doesn’t seem to have really caught on, perhaps because it’s limited to 4W, figure on running two or three cables out to the camera.

So what about the alternatives? Well let’s start with USB. Every computer has a USB port, so there’s no need for a framegrabber, making it seem attractive. But when you dig down into the details the problems start to emerge. The basic issue is that USB is something of a processor-hog, thanks to its employing a master-slave architecture. There are also bandwidth issues, meaning that a significant proportion of its 480Mbps is not available to transfer image data. For these reasons few manufacturers of industrial cameras have ventured into this standard. (Scientific and astronomical cameras are a different matter of course because they don’t need high data rates.) The maximum cable length of 5m can also be bothersome in many applications.

And then there’s FireWire, IEEE1394, to use its proper name. 1394 cameras, which need no framegrabber and take their power – up to 45W – from the single cable, come in two flavors, a) and b), the difference being speed. Roughly speaking, a) handles 400Mbps while b) hits 800Mbps. That’s more than enough for a 2Mp camera running at 5 fps, so what’s the problem?

Well first, cable length is limited to 4.5m, which can get to be a problem in even the simplest of industrial settings. Second, and I’m speaking from personal experience here, it’s just not totally reliable. I’m not up in all the details of error detection methodologies, but it’s my understanding that 1394 doesn’t have any. That means a frame can be dropped and you’ll never know. Now in many applications that might not be a problem, but if you need to be 100% confident in your system, think carefully before going this way.

That brings us to GigE, strictly speaking, GigE Vision. This uses plain old network cabling, though you should upgrade to the better shielded CAT 6, to transmit up to 1Gbps of image data as far as 100m. You will need to buy a special purpose card for your PC – the regular network card can probably not handle Jumbo Frames and in any case, you need it for internet and intranet access – but these are far less expensive than a CameraLink grabber. And if power cabling is a concern, Power-over-Ethernet (PoE) will deliver up to 13W – enough for most cameras.

Downsides? Well really, just the fact that you’re limited to 1Gbps, which is more than FireWire b) can offer, so it’s enough for run-of-the-mill applications.

As for resolutions going up, well you knew that already, didn’t you?

GigE versus FireWire

I’ve found the GigE camera interface pretty easy to use, providing I use a card with the Intel Pro 1000 chipset, so I’ve not spent much time comparing it with FireWire. But a recent Technical application Note from Point Grey has me reconsidering.

“A Guide to Transitioning from the Flea3 FireWire to the Flea3 GigE Camera” (revised May 18^th, 2011,) provides an interesting comparison of the two standards. I recommend downloading the note in its entirety, but for lazy readers I shall cut ‘n’ paste what I consider the most salient points here.

GigE has higher data throughput but places a higher load on the CPU. “GigE Vision applications may consume more resources because the CPU must process both data packet handling and image processing tasks. The CPU in FireWire systems handles only image processing tasks because data packets are delivered directly to main memory using direct memory access (DMA).”

FireWire may be superior for multi-camera applications. “The FireWire bus provides dedicated bandwidth and guaranteed timing for data packets, which guarantees packet delivery, particularly on systems with multiple cameras on the bus. In contrast, the User Datagram Protocol (UDP) used by the GigE Vision standard provides no guaranteed transmission or fixed timing mechanism.”

FireWire is a single cable solution (power is included.) In contrast, GigE (unless PoE,) needs a separate power supply.

Now I tend to be skeptical each time a camera vendor tells me that they’ve chosen the best solution. As Mandy Rice-Davies almost said, “Well they would say that, wouldn’t they? But I don’t think Point Grey has an axe to grind on this matter, so it might be worth your while to spend some time in the support area of their website.

Choose your standard

Is CameraLink on the way out? High-end camera maker Adimec thinks so and they explain the logic behind this statement in a white paper entitled “Vision connectivity interfaces.” (You will need to register for the download.)

This well-written document summarizes the pros and cons of the higher-end camera interface standards, GigE, CameraLink, CoaxPress and CameraLink HS. (In other words, 1394/Firewire and USB aren’t interfaces for those who are serious about machine vision.) The writers are careful to avoid hard-and-fast conclusions, preferring instead to suggest that interface choice should be a function of the application. But despite the efforts at objectivity it does seem that the real goal of the paper is to encourage movement towards the CoaxPress standard. (Of course, it may well be that this emerging standard really does offer the best all-round balance of performance and cost.)

If CoaxPress is new to you, the really neat thing about it is that it’s essentially good old fashioned coaxial cable. It’s capable of delivering up to 13W of power along with 1.25Gigabits of data per second over distances as long as 130m. It does need a framegrabber, but so do the other high-end interfaces, so that’s not really a negative, and as coax is flexible and robust it ought to help ensure good system reliability without costing the earth.

And what about CameraLink? Well as noted in the white paper, CameraLink has its strengths although many users are frustrated by the 10m cable length limitation. But the big problem is that it’s stopped evolving. There’s no roadmap to higher data rates, - CameraLink HS is not CameraLink 2.0 - and that means a CameraLink-based vision system has no upgrade path.

Choose your interface standard, but choose wisely.

A bolt from the blue

If you were to gather together a hundred machine vision professionals and ask them if they needed another camera interface, what do you think would be the answer?

I’d guess that 90% would scream, “No way! Over my dead body!” while 1% would get goosebumps at the thought of adding another column to all those interface comparison tables. (The missing 9% would be too busy trying to reach the bar to bother answering.)

But according to “Thunderbolt interface rattles placid PC landscape,” (EE Times, March 7th, 2011) that 1% are about to get lucky: another interface is on its way.

Okay, to be slightly less alarmist, I haven’t yet heard it suggested as new interface for machine vision, but if you read the linked article carefully it does suggest that one application would be cameras. And before you rush to dismiss this as a harebrained idea to sell more Intel chips, note that Apple has signed up. Apple, you may recall, was the first computer maker to adopt Firewire, and that had quite an impact on the vision industry, so will Thunderbolt follow suit?

Well let’s review the current interface options. At the low speed end we have USB 2.0 and Firewire/1394a. Shuffling the bits along quicker is GigE Vision, which just trails CoaXPress. Faster still is CameraLink, while leading the pack is HSLink. Then there’s the dark horse, USB 3.0. We know it’s out there but it hasn’t yet made its presence felt.

So do we need Thunderbolt? Well speed-wise, it’s comparable to the fastest CoaXPress, which means we already have options. The EE Times article also suggests that cable length will be limited. So in short, we don’t need it.

But, I have a feeling we may not get a choice. If Apple is using it there has to be a strong likelihood that consumer cameras will also pick it up. (Everyone likes to sell to Apple buyers.) And once it’s in consumer products it will move across to the industrial markets. In short, by 2013 we could be seeing Thunderbolt-based machine vision cameras.

Or it might just die quietly, unnoticed by the majority.

Is this machine vision consolidation?

Interesting news out of Germany: camera manufacturer NET (short for New Electronic Technology) is buying image processing experts iv-tec. I’ve been predicting consolidation among camera makers for some time, but this strikes me as being more like vertical integration.

NET’s niche has really been FireWire cameras, although they do sell the Eyespector smart camera family. Meanwhile iv-tec have some serious expertise in digital image processing, as evidenced by these movies on their web site. Machine vision cameras, and especially smart cameras, of course rely on image processing software, so there is some logic to the acquisition. In fact it wouldn’t surprise me in the least to learn that these two companies have been working together for some time, but where is this leading?

Well here’s my hypothesis: iv-tec are doing some interesting things in the field of 3D, especially with stereo image processing. 3D is a growing machine vision application area, especially for the bin-picking challenge, so I would expect to see NET bring out some 3D products in the near future. Now SICK and AT with their structured light products pretty much have the 3D market sewn up, but maybe there’s room for a stereo approach too. If so, NET may be well positioned to be first to market.

Camera sales are booming

A year or so ago “experts” were cautiously predicting slow growth for the machine vision industry. You may however recall that I went out on a limb and said that business was improving much more quickly than the official statistics indicated. Well if lasts weeks record results from Cognex (“Cognex publish full year 2010 results “) didn’t prompt you to send me a congratulatory email perhaps the news out of Stadtroda will.

Stadtroda, Germany is home to Allied Vision Technologies, (AVT for short) and they are loudly trumpeting their 2010 financial results. You can go to the press release for all the details, but let me give you the headlines:

• Overall revenue up 58% over 2009.
• Sales of GigE cameras doubled, while FireWire was up 30%.
  

Comments and conclusions?

• It’s not clear from the press release if sales from VDS-Vosskühler (acquired in January ’11) are being included – I assume not but I’m not familiar with German accounting standards.
• Gigabit ethernet cameras are rapidly coming of age and clearly AVT were very smart in acquiring Prosilica when they did.
  

What’s next, another acquisition? If so, will AVT stick to what they know – cameras – or will they be tempted by a foray into machine vision software?

Only time will tell.

Windows 7 for machine vision

How many of you have started using Windows 7 in your vision projects? My guess is that you’re just begining to, now that XP is no longer available on new PCs. (Okay, you can still get it if you ask very, very nicely, but to all intents and purposes we’re being forced to adopt the new OS.)
Well I’ve discovered there are a couple of features of 7 that might impact what you’re doing.

First, the old Firewire speed limitation is gone. You know how XP SP1 would let you run at no more than 400MB/s, and then SP2 dialed that back to 100? (There was a work around, but it was a PITA.) Well with Windows 7 that problem has gone away. Just plug in your Firewire B cameras and watch the data come flying through.

Now the bad news. No Hyperterminal. Hyperterminal was really useful for talking to simple motion control equipment, but now it’s gone. I’m sure someone has a workaround, so please post a comment and share.

The other interesting aspect of Windows 7 is of course the ability to move to a 64 bit operating system. That ought to eliminate a host of memory management issues, although I haven’t tried it myself. Again, if you have some experience to share, please use my handy-dandy “Comment” function.

GigE supplanting FireWire in machine vision?

Those who’ve tried it seem to like it, the GigE interface I mean. My experience has been that it’s simple to use and reliable, which is really all we want in our camera interfaces, isn’t it? Unsurprisingly then, according to Basler GM Arndt Bake as quoted in “GigE Vision boosts inspection networks,” (Test & Measurement World, August 1st 2010,) GigE adoption is on the rise.

I found this an interesting article in that it addresses how users are dealing with the perceived weaknesses of GigE – latency and CPU loading. The bottom line appears to be that, providing you pick your application with care, latency isn’t an issue. But don’t take my word for it: click the link and read the article.

Another source for machine vision cables

Cables are the unsung heroes of machine vision: if it weren’t for their sterling efforts all that camera work in converting photons to bits would be for naught. Yet so often the cable is an afterthought. And when we do come to hook camera to PC, how often do we find that the cable on hand wont reach, or the connector doesn’t fit? Add to that the need for screw-in connectors and suddenly you’re scratching your head wondering where to go for parts.

Wonder no more, because today I would like to share with you a new cable vendor. Well they’re new to me but I believe they’ve been in business for some time. I’m talking about Newnex Technology Corp.

California-based Newnex offer an extraordinarily wide range of Firewire, USB and GigE cables, and if you still can’t find what you need they’ll even make up a custom cable for you.

Something to add to your “Favorites” if nothing else.