Quantcast
Channel: LabVIEW topics
Viewing all 68924 articles
Browse latest View live
↧

Image color comparison

November 10, 2017, 6:10 am
$
0
0

Hi,

I have a question concerning Labview and Image Comparison.

I would like to know the best way to compute Comparison Image Color (or brithness).

I am acquiring 2 Images at different time with my camera and will like to find out if there is a difference in their Color (or brigthness ?). Using absolute Subtraction of both Images, i can find out if there is a difference between them. but when the difference concerns only the Backgroundcolor or brigthness, how is the best way to represent it. That means if both Images have the same Elements, but differs in their Color, what is the best way to find it out.

I can not use Color or Pattern Matching here because i don't have any Pattern. I am trying to identify any Change of state on a live Screen. I did the first part. Now i want to know how i can Show if it is only a Change of Color or brigthness.

 

I will be pleased if someone has any solution.

thanks

↧
Search

Is AVI file getting compressed ?

November 10, 2017, 6:49 am
$
0
0

Hello All!

I am trying to read and write an avi file with 'Read Write AVI with Data.vi ' i.e  acquire image, and data and write to the AVI File.  This data is saved with the image in an AVI so when the AVI image is read out in the next loop, the same data it was written with can also be retrieved.

When I run it, an original video file of  time 31s gets converted into  the new AVI file created by IMAQ AVI Createwhich runs only for 5s. (The original no of frames is 900 while the same avi file shows the no of frames as 166 ) Somehow the AVI file gets fixed to the following Terms:

1. No of Frames: 166

2. Total Time : 5s

Does the AVI file get compressed when using IMAQ AVI Create? Why is it Happening? Why the total no of Frames are fixed?

↧
↧

Incompatible numeric controls that appear to be the same.

November 10, 2017, 7:18 am
$
0
0

I have some system numeric controls, specifically "System: Numeric: System Spin Control", which is configured as a Double, 64Bit, ~15bit. In the context help window the 15bit is followed by [???]. When I try and connect the output of this control to a write double accessor in my class (or a double indicator) it results in a broken wire.

 

control type question.pngI haven't seen this before, guess, for one reason, I rarely use System controls.

Whaz Up? I can throw a type cast in, but that seems "ugly", would rather understand what is going on.

Thanks, as always.

 

↧

Acquiring and saving a single image from the IMAQdx Grab function

November 10, 2017, 8:44 am
$
0
0

Hi there,

 

For some reason our camera doesn't work if we try and Snap an image so we have been told to use the Grab function. However, when we use the Grab function our program can't run because (we assume) it is attempting to save a continuous feed as one image. Is it possible to extract just one image from the camera whilst it is grabbing? I have attached a screenshot of the relevant section of the block diagram.

 

The error is: "Error -1074360306 occurred at IMAQdx Get Image2.vi"

The possible reason for the error is: "NI-IMAQdx: (Hex 0xBFF6900E) No acquisition in progress."

 

Thank you in advance Smiley Happy

↧

DAQmx NI 9219 RTD Excitation Current

November 10, 2017, 10:43 am
$
0
0

I'm curious whether there is a limit to the excitation current for NI 9219.  I am trying to use an Omega RTD, which requires a 1 mA excitation.  When setting excitation in Labview or NI Max, it gives an error, forcing excitation level to 0.5 mA.  The temperature amplitude is then -410 when degrees F is chosen with the 0.5 mA excitation.  Any thoughts on how to solve this?

↧
↧

One pixel frame for picture control

November 10, 2017, 10:45 am
$
0
0

Hello

How can I create a picture control with a frame of one pixel (instead of 3 pixels by default)?

I would like it to look similar to a Classic Boolean Flat Square Button.

And if possible it would be nice to be able to change the color of this frame with the brush or a property node.

Thank you

↧

SQL Database Progressive Logging

November 10, 2017, 11:44 am
$
0
0

I'm trying to use LabView's Database connectivity toolkit to store temperature and pressure data similar to the method in the example library (below)

 

Create, then LogCreate, then Log

 

What would be the best way to change this vi to log data progressively during a test as opposed to after the system finishes generating data?

↧

reminder how to create a small icon template

November 10, 2017, 12:00 pm
$
0
0

I know I have done this in the past but it is kicking my rear today. I am trying to create an icon template that only surrounds the middle 2X4 terminals of a 4x4 connector pane. I managed, at some point (not today), to create one for the upper 2X4, which, when I type into icon text the text stays within the icon, but today bupkis. When I create a template, or icon smaller than normal, the icon text still fills the whole area, not just that of the template's.

 

About to go back to ugly icons and GUIs! Had a customer looking for a developer to redo the GUI of our project (found out when a recruiter called me), tried to tell them that much of the problem was them needing a good graphics artist to convey their desires to a LabVIEW programmer, but in reality, it would then be a real pain to make work!

 

Thanks,

↧
Search

Make SceneWIndow always visible (3D Picture Control)

November 10, 2017, 12:46 pm
$
0
0

Hi,

 

I am using 3D Picture Control to render a STL assembly and then show it in a SceneWindow. 

The problem is that I cant make this seperate Window be always on top. 

 

This is what I get from property window:SceneWIndow.png

 

 

How to obtain the FrontPanel reference?

 

↧
↧

Creating a control with different options?

November 10, 2017, 1:18 pm
$
0
0

I have an input for a diameter in inches, there are only 6 different options that it can be as I am dealing with specific fan models. Is there a way I can create the control to have the 6 different options as buttons or a drop down menu without using a case structure or radio buttons? Not sure if those would work for this but that's the information I'm getting when searching. Thanks.

↧

How to close a branch after a single use?

November 10, 2017, 2:34 pm
$
0
0

Hi all,

 

I am new to LabVIEW. I have attached my code. I want to have each comparison (5 and 7) only run once. Even if the random number generator outputs another 5, I do not want the LED to light up again.

 

Thank you in advance.

↧

Control Reference created by scripting removed in build

November 10, 2017, 5:38 pm
$
0
0

I have a template VI that is duplicated with another set of VIs. Within, there is a control that is copied, replaced on the VI panel, and, using scripting, a reference to this control is placed on the BD and wired to a subVI. It works and produces a new VI with no broken arrows. 

 

When I build this VI into a packed project library, the references are removed and the resulting VI is broken.

 

Creating and wiring this reference manually does not exhibit this problem. 

 

This problems exists in LV 2014-7

 

Is there some reason why a reference created using VI scripting would not be preserved in a build?

 

↧

labview to excel

November 11, 2017, 5:16 am
$
0
0

I have a program that reads QR codes from an external webcam, i am trying to put the captured QR code data into an excel spreadsheet with my row labels on the left hand side in column A (QR code 1, QR code 2, QR code 3) etc. The problem i have is im not sure how to insert my QR code data into the corresponding rows in column B. 

 

This probably seems like a fairly simple problem to fix but i have only been using labview a few weeks as a student.

 

Any help would be greatly appreciated, thanks.

 

 

↧
↧

labview dll

November 11, 2017, 9:02 am
$
0
0

Hi....

I m trying to create a mobile testing software for mobiles with mediatek processors....

For this I m trying to use DLL library and headers to send command to phone.....

But always I m getting error wen I m trying to create shared libraries from DLL and header....

 

 

Any one know about mediatek processor pls help me with supporting DLL and header....

 

Thank u in advance.....

↧

Scripting: Cast ProjectItem type to VI type

November 11, 2017, 9:43 am
$
0
0

I try to access specific properties of VI found in project tree. However, there is no datatype "VI" among sub-types of "ProjectItem". This is a very simplified illustration.

 

171111_t_Forum.png

 

Which type shall I select to access properties of VI type?

 

Thank you

↧
Search

Hypothesis testing

November 11, 2017, 12:42 pm
$
0
0

I want to make a labview application that lets me test between different types of hypothesis, using different kinds of methods, but I have no statistical background and could really use someone's help.

What I want to do is enter the 2 hypothesis in some text boxes, then select a method to test the hypothesis from a text ring, import the data from a csv, and then read which is the correct hypothesis, based on the result.

If someone could please help me, I would be really grateful.

Thanks.

↧

How to set proper step size for control & simulation loop?

November 11, 2017, 12:58 pm
$
0
0

Hello,

I have adapted an example VI that implements a Kalman filter in a control & simulation loop. By default, the step size for the control & simulation loop is 0.02 seconds, but when I run the program with this setting, the

Kalman filter does not behave correctly (it does not converge to the value I expect it to converge to). I tried reducing the step size to 0.00005 seconds, and it appears that the Kalman filter works better, but is this an untypically small step size? How can I tell that I have selected an appropriate step size (esp. for a Kalman filter)? Is a rule of thumb to pick as large of a step size as possible without affecting the functionality of your program (such that the step size is not so small as to reduce performance)? Thank you.

↧
↧

Load-pull Power contours

November 11, 2017, 2:18 pm
$
0
0

I was trying to implement a code to plot the Load-pull power contours which can show me the maximum output power and the other 3dB power contours but it seems I gave up. 

Is there any of you could help me please with this problem. I wish if there is a ready code for that. the one which is already in the Labview is very slow and doesn't shows me the contours that I want. 

 

 

Thank you in advance for your attension 

↧

NI-DAQmx Icon Missing in Labview

November 11, 2017, 4:12 pm
$
0
0

I had to reinstall LabView and now my NI-DAQmx icon is missing (actually a bunch of DAQmx related icons are missing). I can view the NI-DAQmx icon showing a question mark when go to Tools-Advanced-Edit Palette Set and select Measurement I/O. The path it reports is C:/Program Files (x86)/National Instruments/LabVIEW 2012/menus/Categories/Measurement/daqmx.mnu. As you can see I have LabView 2012 installed (version 12). In NI MAX I can see NI-DAQmx ADE Support 9.5.1,  NI-DAQmx Device Driver 17.1.1,  NI-DAQmx MAX Configuration 9.5.1. Is it because the device driver rev is 17.1.1? Also Measurement Automation Explorer shows Rev 5.3.0f0.

↧

a median filter that is not working as expected

November 12, 2017, 1:42 am
$
0
0

Hello all!

 

I'm using a median filter to process a very noisy signal but I'm not getting the signal I want.

The signal comes from an antenna in a noisy environment(hot, windy, dusty), after envelope detection it is transformed into voltage signal. I use ni usb-6002 to acquire the signal. Here is the snippet of the block diagram I use to process the save the data.1.pngI use the daq assistant to get the signal from usb-6002. Then I save the original data, the data processed by meditan filter.vi, and the data processed by median filter point by point separately as tdms file.

 

Here are two pictures of the raw data plotted using matlab.

1st plot1st plot2nd plot2nd plot

as you can see the data in the first plot contains more noise.

 

Here are the data processed by median filter. 

the first picture shows the data from the 1st plot processed by median filter with left rank=5, right rank=5

median filter with left rank=5, right rank=5median filter with left rank=5, right rank=5

this picture shows the data from the 2nd plot processed by median filter with left rank=10, right rank=10

median filter with left rank=10, right rank=10median filter with left rank=10, right rank=10

I can't upload all the data cause they exceed the size limit. I have attached the 2nd data set in both tdms and m format.

By looking at these two pictures, I think the median filter handles noise that's bigger than the signal pretty well. But it does not take care of the noise that's smaller than the signal. So in the picture,  I can almost see no noise in the upper part but the lower part is still noisy. Why is that? What did I do wrong? 

 

 

 

↧
Viewing all 68924 articles
Browse latest View live
Search
<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>