IMAQ Grab Acquire

What is the difference between synchronize on vertical blanks and immediate transfer in the IMAQ Grab Acquire vi? I noticed that when I use immediate transfer, it is a lot faster. Thanks!

Immediate returns the last full image that was acquired. Non-immediate waits until acquisition of the current image is completed and returns the new image. If you are just doing a fast display loop, using non-immediate keeps you from redisplaying the same image several times.
Bruce
Bruce Ammons
Ammons Engineering

Similar Messages

  • IMAQ 1394 Grab setup and Grab acquire

    Hi, everyone
    I am very new to Labview and have a general question on grabbing images using my CCD camera.
    I set "IMAQ 1394 configure trigger.vi" before " IMAQ 1394 grab setup.vi" and then achieve the most current using " IMAQ 1394 grab acquire.vi".  The configure trigger is on Mode 0 (Low activity) and my digital trigger is a pulse train with a trigger frequency of 10Hz.
    My questions is as follows:
    1. How many images will the camera grab when the trigger turns to a falling edge? Just one or the camera will grab continuously?
    If the camera grab continuously, which image is copied when a "IMAQ grab acquire.vi" is called?
    2 Does the image grabbing process stop when the trigger turns to the rising edge?
    Thanks!
    Attachments:
    IMAQ1394grab.jpg ‏99 KB

    Hi Haiyueli,
    The NI-IMAQ for IEEE 1394 has been replaced by the IMAQdx driver. We usually recommend that you upgrade your driver. That being said, I would recommend looking at the help to determine what the mode does. To do this right click the VI and select Help. This should give you a more in-depth look at the function.
    Here is a forum post which describes mode 1:
    http://forums.ni.com/t5/Machine-Vision/Problem-with-IMAQ-1394-trigger-mode-1/td-p/300534
    Paolo F.
    National Instruments
    Applications Engineer

  • Calling producer/consumer subvi using main vi for image grab acquire

    Hi everyone,
    I am not sure if I get the producer/consumer concept wrong. I tried to write a producer/consumer subvi that simulate continuously grab acquire image. When I call the subvi from the main while loop with a main vi, it seems to run into a infinite loop. I am wondering does anyone know how else can I activate a producer/consumer subvi using main vi? Thanks in advance.
    Kind regards,
    Han Yen
    Solved!
    Go to Solution.
    Attachments:
    MainTrial.vi ‏7 KB
    ProducerConsumerGrab.vi ‏18 KB

    Hi Han Yen,
    a few remarks :
    - your Top VI has no function what so ever.  So skip that.
    - your image queue has no name, so that gives problems from the minute you're going to use more queues.
    - It does not matter which command you send to the queue, it will start the bottom loop anyway
    - You don't have a check whether "live trial" is true yes or no, so everytime you switch it from T=>F or F=>T is will activate the command.
    I've tweeked your producer-consumer.  Maybe this will give you an idea.  I put some remarks in some places
    Kind regards,
    - Bjorn -
    Have fun using LabVIEW... and if you like my answer, please pay me back in Kudo's
    LabVIEW 5.1 - LabVIEW 2012
    Attachments:
    ProducerConsumerGrab.vi ‏21 KB

  • Error - 1074397153 occurred at IMAQ Grab Setup.vi

    The sensor we are using is Goodrich SU640KTSX. I can run SUI image Analysis 3.1 software, Measurement & Automation software, and MATLAB code on an XP machine with no errors when grabbing images. We are tying to build a newer PC;
    Dell T7500 with Intel xeon CPU x5650 @ 2.67GHz 
    Memory; 12GB
    OS Win7  64-bit
    Camlink card is NI PCIe-1430
    Nvidia QUADRO 4000
    The error we get is "Error -1074397153 occurred at IMAQ Grab Setup.vi / Cannot detect recognizable video source" when using the SUI image Analysis 3.1 software or MATLAB code. When we use the NI-IMAQ i/o 2.3.1- Measurement & Automation  I can snap, grab and record without any error. 
    Any help on this would be great
    Thanks

    Hi,
    Let us know which standard your camera is following (whether it is cameralink or ethernet).
    Check this link for error info: http://digital.ni.com/public.nsf/allkb/3434173630CBC97686256F8000536593.
    If at all it is cameralink camera make sure that you are following proper trigger sequence for your camera. As u are grabbing frames in MAX and not in other acquisition softwares it might be triggering issue or cables problem.

  • IMAQ-dx acquires at half the expected framerate

    I have a USB 2.0 camera that I am using with IMAQ-dx. I currently have the video mode set to 640x480 MJPG 30.00 fps. However, whenever I attempt to use the grab function I get frames returned at about 15 fps, with spikes between about 10 and 19 fps. I have tried using both NI-MAX and property nodes to set the framerate to 30 fps, but while I can set it that way, the camera still acquires images at 15 fps.
    Additional information:
    I have a second USB camera that I sometimes use at the same time as a first camera. When both cameras are using the grab function, the framerate is the same as when just one camera is (15 fps). 
    The camera acts the same in both labview 13.0.1f2 and labview 14.0f1. \
    I have attached a simple program that I'm using for diagnostic purposes.
    Attachments:
    camera properties.vi ‏20 KB

    How is your exposure on your cameras and lighting situation?

  • NI-IMAQ Grab Smoothness

    When using the MAX program and all the others that I have avaiable for grabbing an image from the NI-IMAQ 1424 board the image that is displayed is fragmented. Meaning that the image is shifted over(up-down and side to side) and the image is wrapped so that the entire image is there. However, when the snap function is used the image is displayed properly. What could be the possible problems and solutions (if any).
    JAG

    I am also having this problem (as well as some others). I am using the PCI-1424 and have updated the IMAQ drivers to 2.5.1 (w/2.5.3 update) together with a sensors unlimited SU320-1.7RT camera in free running mode (although there are similar problems with the tirggerable version of this camera). The grab problem can be fixed by changing a constant in the LL Grab in IMAQ Vision Display.vi. Changing the memory location from system to onboard makes the grab run smoothly (at least in my setup).
    The problem i have after this, is that the ll sequence doesn't work either and changing to onboard memory is not a fix. The symptoms seem related in that only the first frame and half of the second are new (when grabbing ~10 frames). All the others are holdover from previous aq
    uisitions. Ideas?

  • Acquire the last image of a grab acquistion

    I am performing a tracking operation using labview. I do a grab acquistion during the entire tracking process. After the tracking is done I want to get the last image displayed. How do I do this?

    If you are able to display the image, then you have already "got" the image. Before you destroy the buffer using IMAQ Dispose, just save the image to disk, or do whatever other processing you want. For instance- in the HL Grab example IMAQ Grab Acquire is run inside of a while loop. Everytime this VI is called it updates the image stored in the buffer pointed to by the image data wire. After the end of the while loop, the last image remains in the buffer until IMAQ Dispose is called. You can use this buffer to access the last image.

  • Multi-channel imaging using NI frame grabber

    We have a IMAQ 1408 being controlled by LabVIEW 8.0.
    We wanna setup multi-channel imaging. All the channels work individually. However, when I was trying to show two channels simultaneously, only one channel works, and I got the following error message:
    Error -1074397150 occurred at IMAQ Grab Setup.vi
    Possible reason(s):
    NI-IMAQ: A timeout error occurred while waiting for the specified event. If waiting for an image, verify that all video data is acquired within the timeout period. If waiting for a signal, verify that the signal assertion occurs within the timeout period.
    I sometimes also get another error message asking me to assign different buffer to both channels. I understand that IMAQ 1408 has only one analog to digital converter (ADC) to digitize the incoming video. It can acquire from up to four different cameras, but only from one camera at a time. 
    I don't mind making the frame rate half. So I'm thinking of showing one channel at a time and make the two channels work alternantly. But I need to know how to confige the channels to make this happen.
    Solved!
    Go to Solution.

    Hi Andrew,
    Thanks for the reply! I've read the page. But it doesn't tell me how to assign the buffer.
    Please see attached for my code.
    Here is another error I got from channel 2:
    Error -1074397158 occurred at IMAQ Grab Acquire.vi:10
    Possible reason(s):
    NI-IMAQ: No buffers configured for session.
    Thanks!
    Attachments:
    grab_dual channel 2.vi ‏63 KB
    grab_dual channel 2.jpg ‏41 KB

  • Video acquisition framerate

    Hello,
    I've been trying to acquire images from a camera at 30 fps for time-sensitive image processing. Currently I have a while loop with imaq grab acquire wired to imaq avi write frame. The loop timing is controlled by a wait (ms) function. Obviously the framerate is dictated by the loop timing, which is my main problem. For 30 fps, it is 33.333333 ms per frame which causes a rounding error within the loop timing. Thus, I am getting more frames than I should because it is grabbing frames slightly faster than it should be.
    I'm sure many others have solved this problem, but the solution is not apparent to me. So does anyone know how to properly control the framerate?
    Thanks
    -TJ
    Solved!
    Go to Solution.

    TJ-
    It looks like the bind you are in is because the OS (all PCs actually) and the camera only have a 1kHz clock, so you are stuck with 1ms intervals.  In software, there are always many ways so here you go:
    Hack solution:
    Vary the time of your delay loops:  33,33,34,33,33,34,...  This fixes your round off error, but will give you up to 0.6666ms dither in your signals.
    Better hack solution:
    Feedback to vary the time of your delay loops:  run a timer and use that to set the timing to either 33 or 34 depending on where your <1ms rounding error is at that particular time.
    Expensive, best solution:
    Get a camera you can set the timing in hardware.
    Best solution with what you've got:
    Get off of the windows 1ms timer.  The structure to use is a timed loop (under timed structures in the structures panel).  It will default to your Windows 1ms timer, but you can use any hardware timing you have.  One of your boards will likely have a 1MHz timer, which will improve your timing and dither issues by 1000x.  If you still need more, you can then use some of the hacks above.  
    Ultimately this is a hardware problem and would be 'best' solved in hardware.  However, there are always lots of ways to do it.  In fact, I'm sure the NI gurus can come up with many more.
    Best of luck.  Play around with these fixes and keep learning,
    Casey

  • I am trying to white balance my acquired image, but instead get a green image, has anyone encountered such a problem?

    Similar to Vision's white balancing utility, my VI allows the user to draw an ROI around a region and ideally reset the red, green, blue gains to make the area white. When I make red, green, and blue values equal one another, instead of white, I get a green region. Has anyone else had this problem or know if I am doing something completely wrong?
    Or has anyone tried doing this already and knows of a white balancing algorithm that works?
    Thanks in advance.
    - josh

    Hi Chris,
    I'm using IMAQ ColorImageToArray and I've checked with IMAQ IntegerToColorValue that I'm getting the correct RGB values. I can post my code, however, I am using a QImaging camera which only uses their own VIs to do functions similar to IMAQ functions such as grab setup, grab acquire, initialize, close. The VIs can be downloaded here: http://www.qimaging.com/support/downloads/.
    Thanks again for the help.
    Attachments:
    whitebalance.vi ‏113 KB

  • Acquire continuous images

    i create a pattern matching VI by using Vision builder 6.1. When i run the VI, the program ask me to select file for ome time. when i run the VI in continuous mode, the program keep asking me to select file.
    what I want the VI is to import the live images recieve from the carmera and generate the shape report spontaneously rather than asking me to select file. from folders.
    I attach the VI.
    I am new to computer programming, vision, LabVIEW Please help
    Thank you very much
    nick
    Attachments:
    PatternMatching1.vi ‏84 KB

    Hi, Nick,
    If you only want to acquire one image at a time you will probably want to use IMAQ Snap. Another acquisition method is a sequence, which is demonstrated in the following example program:
    Developer Zone Example: Acquire Sequence and Save with NI-IMAQ
    For more information on the differences between IMAQ Snap and IMAQ Grab, please refer to the following documents:
    Developer Zone Tutorial: Snap
    Developer Zone Tutorial: Grab
    Best regards,
    Dawna

  • Vision builder AI ve labview IMAQ görüntü alma hız farkı ?

    merhabalar
    firewire 1394b kameradan vision builder ile görüntü alıp labview'e migrate ediyorum. bundan ayrı olarak labview içerisinde imaq kütüpanesini kullanarak görüntü alıyorum. migrate ettiğim vision builder kodu daha yoğun olmasına rağmen daha hızlı görüntü alıyor. Bunun temel kaynağı nedir acaba.  
                Eğer  Vision builder dan migrate ettiğim kodları kullanırsam  kamera shutter değerini değiştirmeme izin verilmiyor.
     Teşekkür ederim.
    Solved!
    Go to Solution.

    merhaba sitede mevcut örnekleri denerken buldum. ben snap komutunu kullanıyordum. grab komutu ile desteklenen hızdagörüntü alabildim. Örnekler ektedir.
    teşekkür ederim.
    Attachments:
    IMAQ grab 2010.vi ‏36 KB
    IMAQ grab 2011.vi ‏41 KB
    IMAQ snap 2010.vi ‏36 KB

  • Error -1074397163 at IMAQ inti for USB camera

    I plan to use labview to control a Thorlabs DCC1545M camera. Firstly I want to snap a picture or grab pictures. When I run my program, it show me Error -1074397163 occurred at IMAQ at Snap.vi or at IMAQ Grab Setup.vi. It seems the error come from the subvi IMAQ Init.vi whicn is include in both Snap and Grab Setup vi. When the program run at imgInterfaceOpen.vi under the IMAQ Init.vi, it retrue a number --1074397163 form the return parameter:return type. This is the situation I got.
    The interesting thing is that I could run the similar program successly if I replace the all IMAQ by IMAQdx. It is because my camera is a directshow camera which can not connect by IMAQ? Can I use the IMAQ to snap picture not IMAQdx, What should I do? Thank you so much

    First of all you need to check this.
    And if you have any issue with the Direct Show cameras you need to look at this.
    =========================================
    Please remember to accept a solutions and show your appreciation by giving Kudos to helpful messages...
    Mangesh D.
    CLAD | Project Engineer
    ==
    VIPM, LabVIEW 8.2, 2009, 2011SP1, 2012, 2012SP1, 2013, cRIO,cDAQ, PXI, ELVIS, Multisim, Smart Camera....

  • How to display every other images in image indicator

    Hi All,
    I am using IMAQ to grab and save high freq and high resolution images. I have an image indicator directly from "Image Grab Acquire". So, the image indicator is displaying every single images at a very high frequency too. We have to display frames, but not necessarily every single one (enough so the operator can see what's going on). So, I am wondering how I can display, say every other images (such as all odd/even number of images), or jump over two and display the third?
    Any help will be appreciated!
    Thanks!
    Wenlong
    Solved!
    Go to Solution.

    Here are some general comments.
    Image acquisition is "a horse of a different color" -- unlike many other I/O devices, the memory that holds the data (here called the "buffer") is managed by the driver, and isn't directly available to LabVIEW.
    I'm guessing that you are using NI Video hardware, as you are using IMAQ functions (I've only used IMAQdx).  Is this true?  What camera are you using?
    The IMAQ Extract Buffer (probably) "clocks" itself to the camera (I say "probably" because I don't know the hardware you are using).  This means that the While loop containing it will run at the frame rate of the camera (hence you can easily calculate the frame rate, as your code shows).
    This looks like an NI Demo routine, so I'm guessing that you don't have a lot of experience with Vision processing.  If you've got a lot of other LabVIEW experience, you should be able to make the leap to vision, once you get the idea of how buffers work.  Unfortunately, there's not as much in the way of tutorials and white papers on Vision as on other LabVIEW topics.
    So to your question -- how to display every Nth image.  Here's the key loop (which is lifted directly from your code):
    As menioned above, this routine is "clocked" by the Extract Buffer function.  What you do to display every N'th image is to put the Image control inside something like a Case statement that "fires" every Nth time.  
    Here's an "Nth" version of the above loop (some details omitted) --
    We still drive the loop filling every buffer with a frame.  But we then use the Integer Divide function to select the Nth image (those that have a remainder of 0 when i is divided by Nth) and wire the "image" line (it doesn't really hold an image) to the "Image" control, with the other case being "Default" (so all other valeus go there) and with nothing inside.  Thus every Nth time through this loop, the output of Extract Buffer is wire to an Image (and displayed), the other N-1 times the wire goes nowhere.
    Bob Schor

  • Vision acquision

    Hello All,
      I like to implement this requirement, having start and stop buttons to record the video and store it in a video file for later viewing. 
    Using vision acquisition
     I added "vision acquisition" tool via "vision express" for acquiring video from web cam. I am able to configure and test the video signals well by using the acquisition settings. Even after choosing the "stopped" and "image out" options in the  acquisition settings, they are not appearing on the "vision acquisition" icon(see attachemnt) which is present in the block diagram . Kindly assist me in this regard,
    Using NI IMAQ dx for meeting the above requirements, I shall be using IMAQ open, grab, acquire, close etc. How to store the acquired video.
    which method is best, I am facing problems in both the methods.
    Thanks
    muthu.
    Attachments:
    VisionAcquisition.png ‏42 KB

    For video check this might help.
    Thanks
    uday,
    Please Mark the solution as accepted if your problem is solved and help author by clicking on kudoes
    Certified LabVIEW Associate Developer (CLAD) Using LV13
    Attachments:
    Frames to avi.vi ‏121 KB

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