I've written some code, which currently consists of two windows to show different stages of some processing algorithm. Quite simply, I've created the two windows with cv::namedWindow(), and I'm displaying the cv::Mat with cv::imshow(). I'm having an issue where every now and again, randomly (but not always), cv::imshow() refuses to update the two windows. The program hasn't hung, and I can see that it is still working and processing the incoming frames (as I'm printing stuff into the terminal to show this), it's just that the windows aren't showing the new frames. I've included cv::waitKey(2) after each call to cv::imshow(), however this doesn't help.
This is very annoying, and I can't seem to find anything online. This doesn't always happen, but it does more often than not. Sometimes it takes a few minutes, sometimes it takes a few seconds.
I'm using Ubuntu 12.04 (and Ubuntu 11.10 - this happens on both of my machines with two different cameras) with OpenCV 2.3.1.
One way I've been able to get around that issue is by using
cv::destroyWindow()
after calling a window. This works well if you're just showing a sequence of images, but not so well if you're showing video.
Related
After countless days and hours, I finally can upload my sketch into my NodeMCU successfully. But, just after that, I've got another problem.
If you've checked my previous post, you'll see I have two sketches. The first one is at my question and the second one is at my answer. After uploading the second one, I decided to upload another sketch, which is the first sketch. But when I check the result after the IDE says: "Done uploading", I know that the NodeMCU is running the previous program (which is written in my second sketch) based on what the Serial Monitor has printed. What I want is the result of my first sketch, not this. Anyone can help?
I have some working code that captures the current desktop cyclically and using the code described at DirectX Screen Capture - Desktop Duplication API - limited frame rate of AcquireNextFrame / https://github.com/microsoft/Windows-classic-samples/tree/master/Samples/DXGIDesktopDuplication
This works well except on one machine (where I unfortunately do not have physical access for detailed debugging but only get reports from users). On this machine when I call AcquireNextFrame() with a timeout value of 500, it repeatedly fails with an error code 0x887A0027 / DXGI_ERROR_WAIT_TIMEOUT. To make this clear: the call does not fail only a few times, it fails all the time, so AcquireNextFrame() never returns a result, no matter how often one
When I increase the timeout-value to 850, it fails with an error 0x887A0026 / DXGI_ERROR_ACCESS_LOST.
So...any idea what can cause these errors and how one can prevent it from happen?
Thanks!
The behavior is normal.
Windows does not normally render desktop at 60 Hz, that would be a waste of resources and electricity. DXGI_ERROR_WAIT_TIMEOUT simply means the computer is showing the same image as before. AcquireNextFrame returns S_OK and gives you another frame when some window visible on the desktop has updated something.
I think that one machine doesn’t run any programs which continuously updating GUI on the desktop being captured.
You have to workaround. For instance, maintain a copy of the desktop texture in your capturing app, when AcquireNextFrame returns S_OK update it with CopyResource, when it returns DXGI_ERROR_WAIT_TIMEOUT use the old desktop texture.
I have a website written in ASP.NET MVC (Razor). Recently, a few days ago the images on the website started swapping all over the place. When refreshing the site, it might just hang for quite some time or load all images correctly. So I plugged my iPhone to my Mac and used the web inspector to see whats going on. I found out that at the time of load the browser hangs on certain files. These files are either images or js libraries. The images are very small. Less then 10kb so it is not the size of the image.
This issue only happens on iPhones. I checked on several iPhones.
I have tried multiple Android devices, Mac and Windows computers and they all load fast and every image is in the right place - no issues.
I researched a bit and found out some interesting references to HTTP Pipelining. But if that was is the case, why would these issues start now?
I do not know what to thing anymore.
What am I trying to understand is why would that only happen on the iPhone?
Thank you,
Any clue would be appreciated.
I had the same issue. After months of breaking my head I decided to implement lazy load on all images. After that, swapping never occurred.
Page hanging could happen because of multiple reasons. I would definitely check the code again and in particular look for the way you handled unmanaged resources. More on unmanaged resources
Updates
2016-02-18: Added process information
I have a Delphi program compiled using XE4. It is being used by a few hundred customers. A couple of weeks ago one of these customers reported that some areas of the executable was being erased (images bellow) randomly during the day. This client has 35 sites using this exe and the problem occurs on no more than 10 of these sites.
Investigation
1 - My first suspicion was an infinite loop. The exe keeps responding while the components are erased, nothing changed on the code so radically from the time this problem did'n happen and the logs don't show any loop (this exe has logs everywhere).
2 - Misbehaving threads. I have a separate thread that syncs data between this exe and our server in the cloud. Again, logs don't show that the thread is running when the problem occur and again, nothing was changed here.
3 - Some other program (antivirus?) is affecting my exe. Couldn't investigate this hipotesis properly yet, but until now couldn't find any installed program that raised my attention.
My question is: What could be causing this issue? How can I investigate further? I know this may be a wide question but this is all information I could gather and I can't imagine many more places to look at.
Images
1 - In the image bellow the red-stroked area should be a TToolBar
2 - In this second image there are three areas, from the top to the bottom the first one should be a TToolBar, the second one should be the title of the child form and the third one should be a TwwDBGrid
3 - The third example shows on the top the erased area where should be a TEdit, just bellow it there's what should be a line on a TwwDBGrid and on the side we can see an erased scrollbar from the TwwDBGrid
4 - This last example shows 5 erased areas: The title of the application, the main TToolBar, The title of the Form, a TButton and two TwwDBGrid
5 - This is an interesting example beacause beyond the erased components there are 4 TSpeedButtons that are not erased but they are without the images they have originally (the first red stroked areas). The other 3 red stroked areas are, in order, 2 TEdits, a TwwDBGrd and a TButton
Process Information
I got a screenshot by the momment the problem occurs. scgolr is my software.
There is really not enough detailed information to give you a definite answer. However, I can answer with some directions on your question:
How can I investigate further?
Because of what you have stated:
The program is in use by a few hundred customers
One (only) customer experiences the problem
First occurance of the problem was some weeks ago
the first thing to do, is get in contact with the customer, and get the information you say that you have asked for but not got. The questions that need to be answered are:
What has changed in the customers environment at the time the problem
started with respect to hardware, network, server, OS, other software
running in the PCs?
Has anything changed in the way your customer is using your software?
What do the customer have to do to get rid of the problem, once it occurs? Close the program? Restart the PC? Or maybe just minimize - restore the erroneous window?
With the above I do not suggest that the fault is with this one customer and their equipment or their way of using the software. It may just be that the combination at the site which is different from all your other customers, triggers the problem to show up.
Some specific things to check in your software and at the site when problem occurs and if the problem goes away with a minimize - restore of the application (which would suggest a painting interrupted problem:
Do you call Application.ProcessMessages at any time?
Does the background thread access same data as the GUI? If yes, are the data protection properly in place (locking, synchronisation).
Does the background thread access any GUI components without Synchronize?
Finally I suggest that you visit the customer onsite. You get much better and faster answers in a direct discussion.
Edit after process information received.
There is nothing alarming concerning GDI or User objects. But it is alarming when you say in the comments that you call Application.ProcessMessages in many places, obviously to 'fix' a non-responsive UI. For example, what happens if the user double clicks a button, but does it slowly enough that Windows detects it as to separate clicks? First click may start your long lasting procedure within which you call A.P. The second click is read from the message que which starts the same procedure. Now the second call to the procedure runs (with its own calls to A.P.) and eventually ends and execution returns to the first call. Depending on what you do in this procedure, you may well be messing up handles and device contexts etc. A strong recommendation said with a friendly intent: Get rid of those calls to A.P.
the problem is with the security plugin (Warsaw - Gas Tecnologia) bank's website that your client is accessing , update it and it will be solved , the problem happens in Brazil
As #SebastianZ and #AlekseyK pointed out you may experiment exaustin of some GDI resource (handles?).
If the system coukd be accessed some tools like Process explerer or process hacker could give you some hints. This utility may help too GDIView
I don't know if this may apply to your case, but sometimes database data corruption can lead to strange effect in running programs (i remember 'Data Bombs' causing out of memory exceptions ...
So if something cause a GDI allocation loop, the graphics of your app cauld be affected in 'strange' ways
I have a PIC32MX340F512 board developed by another company for us, The board has a DS1338 RTCC and 24LC32A eeprom, and display unit on an I2C bus, on this bus i included a TSL2561 I2C light sensor, i wrote code in c to poll the light sensor continously , when the light sensor reaches a certain level i save the time and date and light sensor value on SD card. This all works fine but if i leave the system without exposure to light inside tunnel where incident light on one end of the tunnel is ought to be monitored the system becomes unresponsive no matter how much amount of light you apply and then if i switch power off and back on again everything starts to work normal. i am a one man development team and have been trying to find out the problem for months, i activated the watchdog timer to prevent the system from hanging but the problem still persisted. i then decided to find out if the problem is with the sensor by including a push button to activate light measurement but still when 4-5 hours elapse the PIC cant even detect a change in the the input pin. Under the impression that a hardware reset overrides anything going on i included a reset button and it also works ok for the first few hours after that the PIC doesn't seem to be responding to anything including a reset. I was getting convinced that there is nothing wrong with the firmware but also with all this happening the display unit (pic16f1933 and lcd) on the I2C shares power with the main unit and doesn't seem to be affected as it alternates between different messages constantly Does anybody have an idea what could be wrong (hardware/firmware or my sensor). I am using a 24v DC power supply purchased seperately. The PIC seems to go into a deep sleep although i dd not implement any kind of SLEEP mode in my code. Nb We use the same board for many other projects and i haven't come across such a problem . Thanks in advance.
I think you need to (if you haven't already) explore the wonderful world of in-circuit-debugging (such as with the ICD3 or PICkit 2/3). It allows you to run the processor in a special mode that lets you pause execution, see exactly which line of code is being executed, inspect variable values, and step through the code to see which parts are running and not running, or see exactly where execution takes a wrong turn. If the problem takes hours to reproduce, that's okay. You can just leave it overnight running in debug mode and hopefully it will be locked-up or 'sleeping' in the morning. At this point, you will be able to pause the processor and poke around to see if you got caught in some kind of infinite loop or something. This is often the only way to dig inside a running piece of code to see why things aren't working as you expect. But as you say, those bugs that take hours or days to manifest are the trickiest. Good luck!
It sounds like you can break up your design into two main parts, sd card interfacing, reading the rtc and reading the light sensor. If it were me I would upload a version of the code that mimics reading the light sensor but only returns fake data and see if that cures the problem. Additionally do the same with the other two modules separately and see if any of the three versions of your project not show this problem. From there just keep narrowing it down until you find the block of code thats causing problems.
if Two or more versions of your debug code show the same problem then my guess is it has to do with one of the communication protocols. I had a problem with a Pic32 silicon version blocking when using the DMA in conjunction with the SPI peripherals. So I would suggest checking the errata for your chip.
If you still cant find the problem, my only suggestion would be to check for memory leaks or arrays that are growing into reserved memory.
Hope that helps, good luck!