topic Re: LabVIEW & MVTec Halcon in LabVIEW

LabVIEW & MVTec Halcon

dadreamer — Fri, 28 Dec 2012 07:32:00 GMT

Hi, everyone!

I'm trying to connect MVTec Halcon 11.0.1 software with LabVIEW 2011 and got one annoying bug. I have created very simple DLL in Visual Studio 2005 (C++) and then inserted it in LV through Call Library Function Node.When I push Run button everything goes ok. But when I try to close current VI or whole LabVIEW, the program just freezes/hangs up and stops responding to any activity. Here are screenshots of Start menu and Tools window:

This is VC++ code:

#include "stdafx.h"
#include "TestDLL.h"
#include "HalconCpp.h"

using namespace HalconCpp;

__declspec(dllexport) void __stdcall ReadImg()
{
    HImage neu;
	ReadImage(&neu,"C:/444.png");
}

I've tested this DLL on Delphi and everything went allright. Maybe the problem is in memory management as I know LabVIEW does inner memory operations liberating users from this task. Halcon also has COM and .NET interfaces and they both work well without any bugs but they are slightly slow. So I'm interested in DLL approach. Can anybody help me?

Re: LabVIEW & MVTec Halcon

mikeporter — Fri, 28 Dec 2012 21:03:43 GMT

What you describe is a classic symptom of memory management problems. Is there example code available from the vendor demonstrating how to use their library?

Mike...

Re: LabVIEW & MVTec Halcon

dadreamer — Sat, 29 Dec 2012 05:22:20 GMT

mikeporter

There's nothing extraordinary. An user should put #include "HalconCpp.h" and using namespace HalconCpp; in order to use VC++ library and that's all. No object disposing is needed (as described in manual). This is done automatically. I post one of examples from Halcon's help:

#include "HalconCpp.h"
int main()
{
using namespace HalconCpp;
HImage Mandrill("monkey"); // read image from file "monkey"
Hlong width,height;
Mandrill.GetImageSize(&width,&height);
HWindow w(0,0,width,height); // window with size equal to image
Mandrill.DispImage(w); // display image in window
w.Click(); // wait for mouse click
w.ClearWindow();
HRegion Bright = Mandrill >= 128; // select all bright pixels
HRegion Conn = Bright.Connection(); // get connected components
// select regions with a size of at least 500 pixels
HRegion Large = Conn.SelectShape("area","and",500,90000);
// select the eyes out of the instance variable Large by using
// the anisometry as region feature:
HRegion Eyes = Large.SelectShape("anisometry","and",1,1.7);
Eyes.DispRegion(w); // display result image in window
w.Click(); // wait for mouse click
}

This program extracts fragment from whole image. I limited it just to reading an image and it caused memory problems described above. There are more operators for generating new images for instance gen_image1_extern - Create an image from a pointer on the pixels with storage management. This operator also goes to trouble as read_image. I tried changing calling conventions, added image disposing, put pointer to my own clearing procedure and even used LabVIEW memory manager's function ClearMem. The bug is still the same. If there's memory conflict, one of NI's developers could say why it happens.

Re: LabVIEW & MVTec Halcon

dadreamer — Wed, 16 Jan 2013 17:28:57 GMT

I've got solution to the problem. Maybe, someone will consider it useful.

One of MVTec's specialists wrote me the following:

When using libraries on Windows systems it is not allowed to unload a Dynamic Link Library (DLL)
while unloading another DLL. More explicit, when you load a DLL which then loads another DLL then
you need to make sure that the second DLL is unloaded or at least inactive when unloading the (main)
DLL.

Since Windows may have different dependencies to these libraries it can happen that the process will
run into a dead lock. This is why the second DLL needs to be inactive.

In this case LabVIEW will load the custom library which then loads HALCON. When unloading the custom
library it will also unload HALCON which causes the process to be stuck.

To avoid this situation you need to close running threads in the HALCON library by calling the
following operator BEFORE the custom DLL will be unloaded:
set_system('thread_pool', 'false')

Another option would be to set the global library variable HShutdownThreadPool = FALSE.

Please see the HALCON Programmer's Guide chapter "3.2 Terminate HALCON Library" for more
information.

Re: LabVIEW & MVTec Halcon

ydzheu — Sat, 19 Apr 2014 15:32:01 GMT

now the latest halcon vesion is v11

Re: LabVIEW & MVTec Halcon

ydzheu — Thu, 15 May 2014 13:51:22 GMT

if you don't use c to package it,how can you use halcon in labview？

Re: LabVIEW & MVTec Halcon

ydzheu — Thu, 15 May 2014 13:51:22 GMT

if you don't use c to package it,how can you use halcon in labview？

Re: LabVIEW & MVTec Halcon

rolfk — Thu, 15 May 2014 18:19:28 GMT

@ydzheu wrote:

if you don't use c to package it,how can you use halcon in labview？

Unless Halcon provides a ready made LabVIEW Library to their DLL, none really.

Re: LabVIEW & MVTec Halcon

dadreamer — Thu, 15 May 2014 18:27:12 GMT

ydzheu

Halcon also has .NET and ActiveX interfaces so you could easily use them in LabVIEW. Take a look at this thread.

Re: LabVIEW & MVTec Halcon

sumeeth — Tue, 31 May 2016 12:47:06 GMT

anybody please help me and send the Lab VIEW code, DLL for capturing and comparing images in Lab VIEW using Halcon 11

Re: LabVIEW & MVTec Halcon

dadreamer — Tue, 31 May 2016 14:14:29 GMT

sumeeth

Have you tried to use .NET or ActiveX interfaces of HALCON in LabVIEW? What kind of DLL do you need for your app? Which device you're going to grab image data from (real camera / framegrabber or virtual one)? Do you have any test VIs you are working on?

Right now there are more questions than answers.

Re: LabVIEW & MVTec Halcon

sumeeth — Wed, 01 Jun 2016 05:54:18 GMT

halcon.net.dll is using to grab image from camera but i dont lknow how should i use those dll

Re: LabVIEW & MVTec Halcon

sumeeth — Wed, 01 Jun 2016 07:51:37 GMT

i have created a VI to capture an image, how should i compare the 2 image in lab view using halcon.dll

Re: LabVIEW & MVTec Halcon

dadreamer — Wed, 01 Jun 2016 07:59:46 GMT

sumeeth

So, my conclusion is that you're going to use .NET libraries to communicate with HALCON in LabVIEW. Then you should use halcondotnet.dll, located in C:\Program Files\MVTec\HALCON-[version]\bin\dotnet35 folder. I guess you already have working code made in HDevelop environment. To translate that code to LV you should be aware of using .NET nodes such as constructor, property / invoke node / close reference. Start with object constructor node from Connectivity -> .NET palette. Place it on BD and do RMB -> Select Constructor on it. Then you locate your library and choose an object you are going to create such as HFramegrabber or any other according to your code. After that you place Property / Invoke Nodes and connect them to your constructor. In these Property / Invoke Nodes you should select a property or method to apply to your object such s GrabImage() or similar. After you have finished with that object you should dispose it with Close Reference. That's pretty simple if you try.

HALCON also provides simple graphic window to visualize your images. It could be created by placing .NET container on FP, choosing halcondotnet assembly and HWindowControl object from it. After that you're able to output any HALCON images to this control with the help of Property / Invoke Nodes,

Please, take a look at the manuals shipped with HALCON, which are located at C:\Program Files\MVTec\HALCON-[version]\doc\pdf\manuals folder, e.g. programmers_guide.pdf and especially Part IV Programming with HALCON/.NET section.

Re: LabVIEW & MVTec Halcon

dadreamer — Wed, 01 Jun 2016 08:06:12 GMT

sumeeth

First, make working code for image comparison in HDevelop program. Second, after you're satisfied with it, you have to translate the code to LV using .NET assemblies. Now I cannot offer you some samples of image comparison through HALCON in LV but you could experiment with it.

Re: LabVIEW & MVTec Halcon

sumeeth — Fri, 03 Jun 2016 09:30:20 GMT

Thanq so much

Re: LabVIEW & MVTec Halcon

MTrivedi — Mon, 16 Oct 2017 10:33:00 GMT

I face same problem when I create dll of halcon function in visual studio and call that dll in LabVIEW by using call library function by node . Function work properly but LabVIEW goes in not responding mode

Re: LabVIEW & MVTec Halcon

MTrivedi — Mon, 16 Oct 2017 10:34:01 GMT

Please help me to find solution of this problem

Re: LabVIEW & MVTec Halcon

dadreamer — Mon, 16 Oct 2017 14:32:13 GMT

@MTrivedi wrote:

Please help me to find solution of this problem

Have you tried calling set_system('thread_pool', 'false') in the end of your program? That should work for sure.

Re: LabVIEW & MVTec Halcon

MTrivedi — Tue, 17 Oct 2017 06:20:16 GMT

Yes I tried it but didn't work

Will please tell me where exactly place it