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I have a C# program that has been crashing after a variable amount of time. I've tracked it down to OpenALPR and have now duplicated the problem in a test program.

I basically ask to get the plates from an image in a while loop. It fails after a bunch of iterations. Failed after Iterations : 179, 221, 516, 429, 295, 150

Program output:

...
  Iter (219)  No Plates Found in image 71197e9d829d4d429e74a71c983380dc_09032015
134103267.jpg
Config file location provided via API
LBP Time: 0.005ms.
Total Time to process image: 1.916ms.
  Iter (220)  No Plates Found in image 71197e9d829d4d429e74a71c983380dc_09032015
134103267.jpg
Config file location provided via API
LBP Time: 0.003ms.
Total Time to process image: 4.071ms.
  Iter (221)  No Plates Found in image 71197e9d829d4d429e74a71c983380dc_09032015
134103267.jpg
Config file location provided via API

Failure message:

Unhandled Exception:
Unhandled Exception: System.AccessViolationException: Attempted to read or write
 protected memory. This is often an indication that other memory is corrupt.
   at openalprnet.AlprNet.Dispose(Boolean )
System.AccessViolationException: Attempted to read or write protected memory. Th
is is often an indication that other memory is corrupt.
   at alpr.Alpr.{ctor}(Alpr* , basic_string<char\,std::char_traits<char>\,std::a
llocator<char> >* , basic_string<char\,std::char_traits<char>\,std::allocator<ch
ar> >* , basic_string<char\,std::char_traits<char>\,std::allocator<char> >* )
   at openalprnet.AlprNet..ctor(String country, String configFile, String runtim
eDir)
   at AlprTest.Program.Main(String[] args) in C:\Users\foo\Desktop\c#LPR\A
lprTest\Program.cs:line 25

One time, I also got part of another error message(not sure if its related or not) : Unable to load regex: @###@@. Although the error above is pointing to the CTOR, I have, in my normal application, had it fail during the recognize call. I've also seen (not sure how accurate these stack traces are) it in openalprnet.AlprNet.Dispose(Boolean) which was called from alpr.Alpr.{ctor}(...

My test program :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using openalprnet;

namespace AlprTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string chipPath = "71197e9d829d4d429e74a71c983380dc_09032015134103267.jpg";
            string confPath = Path.GetFullPath(".\\openalpr.conf");
            string runtimeDirPath = Path.GetFullPath(".\\runtime_data");
            int i = 0;
            while (true)
            {
                ++i;
                try
                {
                    // Look at target velocity and pick a conf file to use.
                    //
                    AlprNet alpr = new AlprNet("us", confPath, runtimeDirPath);

                    if (!alpr.isLoaded())
                    {
                        return;
                    }
                    // Optionally apply pattern matching for a particular region
                    alpr.DefaultRegion = "va"; // was md
                    alpr.DetectRegion = true;

                    AlprResultsNet results = alpr.recognize(chipPath);

                    if (results.plates.Count < 1)
                    {
                        Console.WriteLine("  Iter ({1})  No Plates Found in image {0}", chipPath, i);
                    }
                    else
                    {
                        int j = 0;
                        foreach (var result in results.plates)
                        {
                            Console.WriteLine("Plate {0}: {1} result(s)", ++j, result.topNPlates.Count);
                            Console.WriteLine("  Processing Time: {0} msec(s)", result.processing_time_ms);
                            foreach (var plate in result.topNPlates)
                            {
                                Console.WriteLine("  - {0}\t Confidence: {1}\tMatches Template: {2}", plate.characters,
                                                    plate.overall_confidence, plate.matches_template);
                            }
                        }
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Exception caught in LPR processing.  Ex={0}", ex);
                    return;
                }
            }
        }
    }
}

The program depends on the openalpr distribution and corresponding opencv dlls. openalpr-net.dll, liblept170.dll, opencv_core248.dll, opencv_features2d248.dll, opencv_ffmpeg248.dll, opencv_flann248.dll, opencv_highgui248.dll, opencv_imgproc248.dll, opencv_objdetect248.dll, opencv_video248.dll. It also uses a runtime_data directory (which I simply copied from the sample app) which seems to contain training data and such.

So, obviously, I'm using C#. I'm using Visual Studio 2010 and .NET 4.0

I'm assuming that I'm using OpenALPR wrong and that there is, in fact, nothing wrong with it. This would seem to be a pretty basic function. Aside from fixing it... why does this crash my program and how can I catch this and recover? You notice my try-catch totally fails to catch it and it crashes the whole application.

EDIT : While running the test app, it starts with like 2gig of memory, but it just grows and grows and grows. It crashed with 7.7 gig after 147 loops.

EDIT EDIT : Added in call to Dispose after each iteration and now the program sits pretty steady at 50-75 megs of memory.

4

1 回答 1

1

原来问题出在 Dispose 上。

需要Dispose的对象。更好的是，不要丢弃该对象并重新使用它。只要配置不改变，您就可以重用该对象。可悲的是，prewarp 在配置中，因此您可能无法重用该对象。Dispose在对象离开范围之前调用。

            try
            {
                // Look at target velocity and pick a conf file to use.
                //
                AlprNet alpr = new AlprNet("us", confPath, runtimeDirPath);

                if (!alpr.isLoaded())
                {
                    return;
                }
                // Optionally apply pattern matching for a particular region
                alpr.DefaultRegion = "va"; // was md
                alpr.DetectRegion = true;

                AlprResultsNet results = alpr.recognize(chipPath);

                ...

                alpr.Dispose(); // Dispose of the object so it can clean up
            }
于 2015-10-21T19:52:45.430 回答