Camera image as local variable

Hey,
I am looking to use the same image out reference for each of my camera inspections. I take an image at the start of my test i call this camera image1, later on i perform numerous test inspections, however, my camera1 image is blank for the first 5 steps but displays an image for 3 steps then gives a blank image at the end again. I created a local variable of the image out reference. Any suggestions helpful. Thank you.
Damien
Solved!
Go to Solution.

Hi Damien129,
Are you able to upload your VI here for me to take a look at.
Something to bare in mind is that the value from image out is not an image. The value is a refernce to the temporary memory location where that image is stored.
Kind Regards
Kevin R
Applications Engineer
National Instruments UK&Ireland

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How to use local variables to pass an image mask correctly

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Thanks,
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So i attached 2 snapshots of the program to give a better idea of the problem. The first snapshot shows an image getting written to the local variable SavedMask. The second snapshot, which is run on the next iteration of a while loop, shows the local variable SavedMask being read to other image operations. When i run the program, the SavedMask image is always displayed correctly on the front panel, but i can't read from it for whatever reason. I think the problem could be like you said, that im only passing an imaq reference, and i think theres a certain way to extract the image data. Do you know the correct way to extract the image data or how to pass the image data and not just a reference to the data.
Attachments:
first.jpg ‏81 KB
second.jpg ‏68 KB

Local variable without frontpanel object

is there a possibility to create local variables without the need of a frontpanel object? I need zhem for program ccontrolontrol but don't want to show them to the user.
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greetings from Germany
Karin

Lynn, Marc, and "tbob",
Thanks for your replies. I detect the common theme of keeping my variables in bundles, but I'm not experienced enough to see how to apply this to my problem of communicating between parallel event handlers. If you have the time and patience, I have attached a very simple example of what goes on in my program.
I have three independent systems: a motion system that carries around a microscope and digital camera. Each system has its own event handler. The motion system responds to user commands to move the microscope around, the microscope handler responds to changes in focus, zoom, etc, and the camera event handler continuously snaps pictures to provide a "live" image.
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Data Acquisition - using local variables to write data to a file

Hello,
I am running a Data Acquisition vi (currently in LabVIEW 7.1 but soon to be updated to 8.2) that collects ~100 parameters of data from several sources contained in a while loop. The current configuration (which I did not write) uses very few subVIs and writes to ~100 local variables to store each parameter. It then reads all the local variables and builds an array of all the strings, converts then to a spreadsheet string, then uses the write characters to file function to append to a datafile. I am trying to clean things up and have came up with subVIs to collect the data from the following sources:
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Hi jilla,
jilla wrote:
What I think that you are saying is to turn the outputs of the 4 subVIs into inputs of a 5th subVI that writes to the data file. Correct?
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One more question: at what point (either # of data points or frequency of data collection) does it become necessary to use queues? Thanks.
Well, there's not really a clearly definable "point". I'd say if your update-rate climbs above 100Hz, or you witness poor program or system performance, then it's time. The scenario you've described is a fairly simple acquire/display&log loop - and simple is good. Then-again people can't see/react-to updates faster than about 10Hz - so it doesn't make sense to sacrifice performance - if performance becomes an issue.
Re: queues: Queues are sometimes used to buffer data that's "produced" in one place and "consumed" in another.
Here, if/when logging data, you're logging with every DAQ. I wouldn't recommend using a queue to transport data from a "DAQ loop" to a "Logging-loop" - those functions can be in the same loop. Should/could a queue be used to get data from a "DAQ loop" to update the GUI at a lower frequency? Sure, but a Notifier might be a better choice. Further, in the (simple?) program you've described, you might use a case structure (True/False) to only update FP indicators every "X" iterations - a simple solution that doesn't require Queues or Notifiers.
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"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

How can I use local variable in LabVIEW-Action?

Hi All!
There is local variable (for example "MyVariable") in local scope of project. There is Action-step, created by LabVIEW. One of input terminals step is "Sequence Context".
How can I access to MyVariable by Sequence Context? Unbundle? It does't work.
Thank you.

On the TestStand palette there is a VI called TestStand - Get Property Value.vi. Use that. Attached is an image showing how to use it. The trick is making it produce the correct data type. Do that by right clicking on the VI and selecting Select Type. Then you can choose the type. I think in LV 2010 and TS 2010 it is a polymorphic VI and you can just change it. I wrote an example here for Chaz: http://forums.ni.com/t5/NI-TestStand/How-to-execute-two-steps-in-parallel/td-p/1449874
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~Will work for kudos and/or BBQ~
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No difference between using a local variable and a notifier in timed parallel loops?

The example code "Pass Data With Notifiers.vi" that came with LV 7.1 illustrates using notifiers with parallel loops. Just looking at two of the loops, the one that generates the sine wave and the one for "User 1", you can change the timing of the two loops and you can change the condition of the "Ignore Previous" status on the "Wait on Notification". I have a special case of this to consider, where I'm wondering if there's any reason not to use a local variable instead of the notifier:
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Hi H.,
I think your idea is to write to a Global Variable in the data-producer VI, and read it in the data-consumer VI(?)
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> since each time the [consumer] loop timer runs the loop there will always be a value in the notifier...
> Would there be a performance difference between the two methods?
If you don't use the Notification "event" to synchronize the producer and consumer, then to be sure the consumer gets a new vaue, you've made the producer loop faster - every 5 ms - a waste of cpu-cycles. More often the situation is reversed, that is, there's a consumer that needs to see every single new value, and (without events) the consumer must loop faster than the producer (to catch every new value) - this is called polling and it wastes cpu-cycles.
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tbd
Message Edited by tbd on 07-09-2006 03:51 AM
"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

Local variable accessed within inner class

Hey everybody,
My program keeps telling me that it wont work because one of my methods is calling a local variable inside an inner class. Does anyone know what this means and how to fix it?
Heres the code:
public class SliderExample extends JPanel{
int value=0;
public SliderExample(int imw, int imh, Image img, BufferedImage buf, Graphics2D biCon){
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g.drawImage(im,value,0,iw,ih,this);
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biC.drawImage(bf,value,0,iw,ih,this);
Any ideas???
THanks,
Rick

Its getting them from another class thats calling the mothod to construct the slider bar with dedraw button. Thats a pretty big class but I will post the code where I called the method:
public class Process extends JFrame implements MouseListener, MouseMotionListener{
private int [][] points;
private int [] lengths={0};
private int [] bin;
private String imstr;
private String imsav;
private int imgw=658;
private int imgh=512;
private int xArrayPos=0;
private int yArrayPos=0;
private int xpos=0;
private int ypos=0;
private int xprev;
private int yprev;
private int xadd;
private int yadd;
private String filstr;
Image image;
SimpleGUI gui;
BufferedImage buffer;
Graphics2D biContext;
Graphics2D g2;
BufferedImage last;
Graphics2D lastContext;
public Process(){
JFrame slideFrame = new JFrame("Please slide to scroll image");
slideFrame.setContentPane(new SliderExample(imgw, imgh,image,buffer,biContext));
slideFrame.pack();
slideFrame.setVisible(true);
Thats what anything having to do with that function in the other class that calls the Slider Class.
Do you know how I can fix this??
Thanks,
Rick

Save image to local folder

Hi,
I am using Labview to out put the images from a external camera. There is a 32bit 2D array output integer. How can I save the image to local folder. I have used following functions. Even though the program runs just fine, there is no image saved not even an unreadable file.
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Thanks!
Tedan
Attachments:
Capture_saveimage.JPG ‏30 KB

Try wiring the error output of the Write JPEG File VI to an indicator. Maybe something is going wrong there behind the scenes. Also couldn't hurt to probe the Pixmap wire, to confirm it contains some real data.

I want to fill and empty a tank automatically can this be achieved without the use of local variables?

Gurus of Labview,
I have a Project to complete and i am new to labview, I have student version 2009. and want to build an initial vi of a Municipal water trteatment plant TO FILL AND EMPTY TANKS. I am using the DSC module to help and I can get my tanks to complete a sequence, however it uses local variables. They cannot be shared on the network when I create my libraries. Need help urgently..
Casey74
Solved!
Go to Solution.

Casey74 wrote:
Here is the block diagram for your enjoyment.......
Sorry, I cannot "enjoy" an image. It would help much more to see the actual VI.
LabVIEW Champion . Do more with less code and in less time .

What is difference between local variable and property node ?

What is difference between local variable and property node ?
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To make things clear, here are two small examples that show how nasty locals and value properties can be to the naive programmer.
- Open the diagram of the race condition.vi before running it and try to predict what will be the values of the two counters after the third run.
- Use the Compare Locals Properties and Wires.vi to find out how slow locals and value properties can be (times 1000+).
This being demonstrated, I must add that I use globals and value properties quite often, because they are often very convenient
Chilly Charly (aka CC)
E-List Master - Kudos glutton - Press the yellow button on the left...
Attachments:
Race condition.vi ‏9 KB
Compare Locals Properties and Wires.vi ‏18 KB

How to use local variable in member formula?

Hi Expert,
We would like to use a {local variable} in a member formula, so that it can pick up the prompt from webform upon save. Would like to know if it is possible to do? If so, what is the correct syntax?
We attempted to use brace {scenario}, blacket [scenario], blacket with quote ["scenario"]. None of these work.
We are using 11.1.2.1 version, EPMA, Hyperion Planning.
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One other pointer. Where did you define your variable? Hopefully you went into Calc Manager and selected <Tools>, <Variables>. From there, navigate to your application or database. Right-click on your application or database and select "New". In the bottom panel, you'll need to select your Variable Type. Make sure you select "Member", and not "Members". You cannot pass "Members" (plural) to a web input form. Also, if you want to define a variable for a custom dimension, you'll need to do it at the database level. Standard dimension member variables can be defined at the app level. (Not sure why this is the case, especially when my custom dimension exists in all plan types . . . . )
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Default initialisation of member variables and local variables

I don't understand why member variables are initialized with default values by Java.
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If these variables are used locally they are not initialized. The compiler requires them to be initialized by the programer, for example "String s = null".
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Most of the time I have to initialize a local variable
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otherwise the compile would complain. This is a cheap
little trick, but I think everyone uses it.
I wouldn't agree with "most of the time". The only cases where it is almost necessary to do that is when the variable should be initialized in a loop or a try-catch statement, and that doesn't happen too often.
If local variables were initiliazed automatically without a warning it would be a Bad Thing: the compiler could tell when there is a possibility that a variable hasn't been assigned to and prevent manymanymany NullPointerExceptions on run time.
And you didn't answer me why this principle is not
used with arrays if it is so useful as you think.
Possibly it is much more difficult to analyse the situation in the case of arrays; what if values are assigned to the elements in an order that depends on run time properties such as values returned from a random number generator.
The more special rules one has to remember, the more
likely one makes errors.I agree, but what is the rule to remember in this case?

How can I Change data in a type def control containing a Xcontrol with a local variable

Hello
I made a Xcontrol and I inserted this control in a type def.
When I want to change the control's data with a local variable in a VI, the VI change nothing. The change of data isn't perform
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Thanks for your help
Solved!
Go to Solution.

Hello,
What's your LabVIEW version ? Do you have a simple example program which demonstrates this behavior ?
I found another discussions related to your issues with Xcontrols:
updating type defs in Xcontrol Facade
No Data Change event generated for a XControl in a Type Def
XControl facede.vi
Hope this helps.
Regards,
Steve M.
National Instruments France
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Control buttons in local variables

hi,
i have been trying to do this for a long time. i just never learned how to make it work. can someone please guide me?
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Attachments:
test.vi ‏768 KB

does this work?
i split up the zip file to 2.88mb each.
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test.zip ‏1078 KB
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Reference to a local variable object returned by a method is alive?

I have an instance method getEmployee().
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How does it work in case of Java?

No, It rarely has any use but can be used to unload things (from a cache for example). However I have never needed to do this. All I know is that finallizers can only be relied on to clear up memory. How or why you would do this is another question.
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http://www.excelsior-usa.com/pdf/StackAlloc.pdf
This can handle some finalizers
This does not handle finalizers (marks them all as GLOBAL_ESCAPE
http://delivery.acm.org/10.1145/330000/320386/p1-choi.pdf?key1=320386&key2=0718563811&coll=Portal&dl=ACM&CFID=15151515&CFTOKEN=6184618
bit more recent and about runtime optimization (finalizers not handled)
http://ssw.jku.at/Research/Papers/Ko05/Ko05.pdf
I don't think that not handling finalizers is too much of a problem. Most objects that will benifit from stackability are small objects anyway (especially the built in wrapper types). Most objects that have custom finalizers tend to be pretty complicated.
matfud

Camera image as local variable

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