Different Vision Systems

[Bob O]

I have only work with DVT cameras so far but I am thinking about looking at other systems so I know what I have or don’t have with DVT systems. I know some of you have worked with multiple systems so I was wondering if anyone would like to share their opinions about the different systems. Thanks, Bob

[Pat Allen]

Hi Bob, I've worked with a couple of different vision systems, including several DVT cameras, Cognex In-touch, and LabVIEW Vision with an inexpensive Firewire camera. In my opinion, the "best" system depends on what you want out of it and how much you're willing to pay for it. Not to mention how much time you want to spend programing it. We've had good success with DVT systems in the past. But I wasn't too happy to hear they're now charging for firmware upgrades. Even when said upgrades are basically bug fixes. We've had a few cameras fail. But for the most part they've been pretty reliable. I liked the FrameWork interface. But was again disappointed when their "new" software ended up being incompatible with any old project. We never did do any developing in Intellect. As a LabVIEW programmer I have an edge when it comes to the LabVIEW Vision Module. So maybe I'm a little biased in my preference for that system. Where we plan on using a PC, LabVIEW has been the most cost effective solution for us so far. There are many sub $100 cameras compatible with the system, as well as several very high end ones. When LabVIEW is already being used for controls or data acquisition on a machine, the Vision data is very easy to incorporate and pretty much anything can be done with it. There are embedded controllers for the LabVIEW vision module as well. But they are pricey. We don't consider them to be a value unless the controller is being used for at least three or more cameras. -- Patrick Allen

[JRoss]

I've only worked with SICK|IVP vision products, so I can't make any good comparisons. However, I've been favorably impressed with the capabilities and flexibility of the IVC-2D and IVC-3D series. The IVC-2D is a standard smart camera that comes in five versions: low-res, high-res, low-res Reader, high-res Reader, and low-res Reduced Performance. Low-res versus high-res indicates the pixel count. The Reader versions add barcode, DataMatrix and OCR. The Reduced Performance is simply a slower version, and is less expensive. Other than that, there isn't much else to say that probably can't be said about other smart cameras. The correct lighting is the key to the application. They are competitive with DVT/Cognex in price and capability. The IVC-3D is another story. 3D vision has been around for years. Basically, you shine a laser line across your product and aim a camera at the spot from an oblique angle. From the camera's point of view, the laser line is at different "heights" depending on the profile of the product. By extracting the line from the image, you get a height profile. Combine multiple profiles as the product moves through the field of view, and you've got a full 3D image of the product. In most cases, this is done with a separate laser source and camera, which requires a lot of setup time to get the angles right. Also, it requires a computer to do the image compilation and analysis. The IVC-3D is a one-piece 3D vision smart camera that takes minimal setup time and can operate independently to analyze product. I put together an informational page on our website that contains more information and literature downloads. I do programming and support for these units, and they are pretty fun. I've used them on everything from waffles to ceiling tile.

[Chris Elston]

I've used the following ordered in favorites. Cognex Banner Keyence DVT Omron Sharp bad-Avalon worst-RVSI Vision (frame grabber written in VB) Basically all vision systems are created equal to some respect that I've seen. But I like a system that I can use to "program my way out of a jam". Cognex gives me GREAT flexibility to do ANYTHING I want. I can think of any logic sequence and write it using "Excel;" thinking and solve almost any application I've done. I think I've done over 50+ Cognex installations. Each one is different and fun to program. All the other systems seem to constrain me. Your stuck in their "can-box" software, like DVT and Keyence for example. You have to use their GUI etc...I Cognex because you can build your own GUI without using something like VB to pull it off and it actually makes sense to me. To an End User, I think after support in DVT is cumbersome. If you need to adjust a setting or limits in the vision system you have to know the system (how the vision application was written) and know where to find the tool buried in the vision system and drag your laptop out to make the adjustments. In Cognex, you put all your min-max limits on a Customer Operator screen and you can adjust them on the fly while the machine is running. I am sure by now that DVT probably has made this better. Attached is a document I wrote for an end user one time. They asked me what I thought was better, DVT or Cognex. So I wrote a Pros and Cons sheet. I am also VERY fluent with Excel and VBA scripting in excel, so I feel right at home. But not with full blown VB. The coolest thing I like about Keyence is the ability to MASK an object. That's about the only thing Cognex can't do. You can't MASK out an area you don't want to look at it. With a Keyence you can block out a polygon area up to 16 sides to mask an area. Basically it comes down to this for me: Bigger machines with more than three inspections or measuring - Cognex If I feel the end user can handle a Cognex too. Sometimes you end up burying yourself because if your end user can't use it after your done with your application, then what good is it? Cognex is tough to learn, but building an EASY TO USE operator screen solves that. So it's up to YOU the engineer to design something user friendly so your customer will like Cognex. Smaller machines with very simple vision, I'd pick Keyence. It's EASY to train an end user with ZERO vision experience on a Keyence system than Cognex. DVT is the same way. Their software GUI is easy to use, but from an engineering point of view, I think it's too easy, and NOT flexible. Cognex is complicated to use, looks scary, flexible and open to create what ever I want. Cognex_DVT_mrplc.pdf

[JRoss]

Chako, That's a great run-down! I'd be interested in your opinion of the IVC-2D and IVC-3D if you ever get a chance to use them, especially as they compare to Cognex/DVT (our main competitor). Just some follow-up information about the IVC series from SICK. Programming is very flexible, once you get used to it, but it can be difficult to learn. Lot's of tools are available, and you can bring almost all your "tweaks" into a single area very easily. The exception is on the IVC-3D for the camera setup, but that's all in a single step. There is no "controller" for programming, and you need a laptop to make programming changes. You can set up a user-defined webpage on the camera that can include interface controls, however. Masks and user-defined ROI are available and very flexible. I don't think there's any limit to shape or size. The IVC-2D and -3D use the exact same programming system, IVC Studio, which acts as a programming and diagnostics tool, and also has ActiveX controls that can be built into a VB application. The only difference is that there are special tools for the 3D analysis. The 3D images are stored as B&W, just like 2D, except that white means high point instead of bright point. Because of this, all the 2D tools can be used on 3D. Gotta run, will write more if there's interest.

[Bob O]

Thanks everyone for your feedback. I had never thought to look at LabView but I will read up on it. Chako that is a nice doc. but how old are the comparisons? Were the comparisons done with frame works or Intellect software? Thanks Again, Bob

[Chris Elston]

It was compared against a DVT with the new Intellect Software.

[Clay B.]

I have used DVT, Keyence, Avalon, and Banner Right now I kind of lean toward Keyence. Most for the reasons Chako dislikes it. The canned features are what I like. The problem I have with DVT is time. The feautres I tend to use, Orentation, Pixil Counts, Edge Detection really slows the DVT's down and on 2 aplications I have hit the ceiling of what they can do and still process in time for my process. I converted these over to Keyence and have been really happy with the results. The triple processor setup Keyence uses in their controllers helps alot. I would like a more robust comm system. I have an Avalon system running now and for low contrast product it has been a headache. I have improved it some but it took alot of effort. The one thing I can say for Avalon is I recieved alot of support. I also found that when you start going high speed that lights are everything. High watage diffused lighting for color/print inspection, Changing light colors for part inspection. I actually found that a blue light will make a clearafied product glow. I also use alot of filters on my cameras (regarless of brand) so I do not have to worry about ambient light. For reference the speed I hit the wall for DVT was .15 seconds for what I wanted to do. This was full color print inspection.

[Chris Elston]

I alot forgot to mention Keyence has the SMALLEST cameras EVER. If you want to carry a camera around on a robot arm, which is what I've done before to look at some pins in a mold it's pretty snazzy as well. And you can use TWO cameras on ONE controller...that is a huge savings. Compared to TWO of any other vision system. I wrote an article about Keyence vision as well. http://www.mrplc.com/kb/index.php?page=ind...;id=78&c=37

[Clay B.]

Actually with the expansion you can use 4 cameras. Their standard camera is about 1/2 the size of DVT. The Keyence rep showed me the really small one I think you are talking about. What I also liked about their standard cameras was that I could still use my standard filters. There is a company out in the midwest( I have the name at work) who will make a filter for whatever light frequency you want. This is real handy when you can not block out ambient light. Starting to sound like a Keyence salesman... I have just been really blown away with the speed.

[Bob O]

I am working on setting up a Keyence demo in the next couple of weeks. It has been a game of phone tag. Clay it sounds like you guys are doing a lot more with vision then we are.

[Clay B.]

We are really just starting. We got lucky with our first attempt, saved the company a bunch of money so they gave us some more to play with. My biggest hurdle now is seeing a clear part, detecting it orentation or shape and acting fast enough.

[panic mode]

I busted one Keyence CV700 by using screwdriver to remove 24V wires from the back of the controller. bad idea...imho this is something that outweights all good sides of it. The whole controller is way too cheesy mechanicaly and begs to be destroyed. For example even slight tension on mounting clips deforms the paper thin housing. this means that controller becomes loose after while (specialy if it happens to be installed in enclosure on a swing arm etc.). But the worst part is how they solved support of the terminals.... Camera connectors are on separate PCB, right under terminal strip and the corner where 24V power comes, support is only 0.5mm plastic tooth (other three corners are supported, but not the 'right one'...). there is no insulation between TB and camera connector and clearance between them is only some 0.5..1mm. it is not hard to bend it with even slight push and destroy the unit. in fact it is necesary to use some force or screwdriver will slip. manual does mention that any wiring should be only done when unit is powered down (yeah, great...). even if it wasn't fine print, i would have done the same... when replacement unit arrived, i placed piece of plastic inside to prevent further accidents. it was very expensive 1"x1" piece of thin plastic taken from an unsuspecting donor - 2 liter pepsi bottle. beware, if you ever want to open controller for any reason, be careful not to loose any pieces. there is a selector sw. knob on the back for choosing local/remote controls. if the housing is ever open even slightly, there is nothing to support it and this thing comes flying out. so far i've dropped few of them but only two ware never found... Cognex is not bad, can't think of any problem with it in the past but right now one of my colegues is using few of those. Everything except character recognition seam to be just great. But the OCR seam to be very poor and there is not much to adjust either. I didn't have much time to look at it but so far this is still a problem...

[andybr]

I have used Keyence in the past and thought that they were quite good provided you were not trying to be too creative with them. I now use Cognex and they are so much more flexible I would not dream of going back. Andybr

[BITS N BYTES]

Vision systems are SOOOOO dependent upon what you are trying to do. Planning to test the new IFM Efector Dualis unit model O2D222. While not a fully fledged vision system [more of an object finder] the demos I have seen for this unit are pretty impressive and extremely easy to set up. Will post results when completed. Anyone had experience with this unit or its earlier model - the good, bad and ugly????

[panic mode]

so far i didn't use it (used other models etc) but i like ifmefector products. i've seen demo for dualis and it is what it promisses to be - a scaled down vision system in a compact inductrial housing, flexible, inexpensive, robust, and simple to use...

[Bob O]

Update....... I had Cognex in to show their color camera but it had to be borrowed from someone who password protected it so long story short, they could show it to me since they didn’t have the password. They did show the software which I am not sure I care for the cell idea but that is my issue and doesn’t make it a bad product. Keyence brought out their set-up which I must say; I really like the small physical size of the cameras but I can’t get past having to program using the remote control. The rep. thought that they would be coming out with a different way to program instead of the remote so I will look at them again when that happens or maybe sooner. Both systems seem to have very similar tools that I saw so there was nothing that stood out with that. Thanks for the replies, Bob

[andybr]

Bob My initial reaction to the Cognex software was the same as yours but in practice I have found the spreadsheet system easy to use and very flexible. My only grouch is that moving large amounts of data using Ethernet IP requires very long strings which can be awkward to enter. Andybr.

[Bob O]

Thanks Andybr. I did learn that the software is now free along with an emulator or simulator. I haven't downloaded it yet but still plan to. Bob

[Bob O]

I have a beta version of the latest Dualis and software that I should be bech testing within the next couple of days. I have already played with it and there were some minor issues to work through but so far I really like what I am seeing. First was a display setting on my laptop it didn't like. My was set on 120 dpi and in needed 96 dpi. Another issue is I need to upgrade the firmware of the beta sensor to match the latest software. I'll let you know more later.