Image acquisition speed

[danilo]

Hello!

I'm programing in VB.

I'm acquairing image vith several IEEE1394 camera in several steps with several diferent setup camera
parameters(Hue, Shuter speed...) in diferent steps.

The solution I'm using at the moment  is folowing:

Step N
    1. Setup camera parameters
    2. Image acquisition with SNAP
    3. Image analysis
Goto Step N

Now the problem is that image acquisition takes 500ms wich is far too long for me.

Do you have any smart solution?

Regards!

[danilo]

I'd like to now if is possible in Grab mode changing camera parameters?

Regards!

[yaHeard]

Hi danilo,

In response to your latest post, yes you can change camera parameters on the fly but not all of them.  Which parameters are you wanting to change?  You may need to reinitialize the camera each time depending on what parameters.

There could be a few reasons your acquisition time is slow.  It would take longer than it should if you are opening and closing a camera session during each step.  A better solution would be to initialize all the cameras at the beginning and then close them after you have run through the various steps.  Is there a specific reason you are using VB instead of LabVIEW?  Using LabVIEW would allow you to run these steps in parallel if needed in your applications.

[danilo]

Hello!

At the moment my only option is VB.

In this application I have I'd like to have big flexibility, so If is possible
I'd like to have all parameters of camera setable.

But basicly at the moment I'm only adjusting shuter delay time.
I'm opening camera sesion at the begining of application and closing them at the end and I'm using
SNAP mode. Picture acquisition step is now around 500ms wich is far too much.

I'd like to now if is possible to use GRAB function for image acquisition. and in mean time
change parameters of camera.

Or do you propose any other solution?

Best regards!

Danilo

[yaHeard]

Hi danilo,

Yes, you can change parameters when using a GRAB to do the acquisition, but the specific parameters you will be able to change are determined by the camera.  Some are read/write while others are only one or the other, but it's not universal to every camera.

Can you give some more information on how you are doing the programming?  Possibly even paste a section of the code in so I can see the exact steps you are using?

[danilo]

Hello!

Now I can change all parameters for the camera.

1. Open camera session

2. Adjust camera parameters( all parameters..)

3. Acquire image(SNAP)

4. Analyse picture

5. Goto point 2 and LOOP until END

I'd like to now if is possible to do folowing:

1. Open camera imaq1394CameraOpen2

2. Setup GRAB   imaq1394SetupGrabCW

3. Set several parameters of camera imaq1394SetAttributeCW

4. Grab Image  imaq1394Grab2CW

5. Analyse image

6. Goto Step 3

7. Close camera  imaq1394Close

Is that possible? The speed of acquisition should be faster?

Wich parameters I shouldn't adjust? Is it possible to adjust

Shuter parameter?

Regards!

[yaHeard]

Hi,

If you are just acquiring one image per iteration then using grab will not give you an added benefit as far as speed.  When acquiring a single image, grab and snap will take about the same time except grab may even have some extra overhead associated with it.  Do you know that it is the acquisition that is taking 500 ms and not the analysis?  The actual parameters you set for the camera will also affect your acquisition time.

I am sorry I wasn't very clear in my last post.  You may be able to change/set all the required parameters for the camera when using snap, but some may not be available for setting in grab.  This is dependent on the specific camera.  You can either use code to get the camera's attributes and if they are read/write or get the settings from the camera documentation.  Coding it as trial-and-error may be quicker for you, though.

[danilo]

Hello!


Thanks for your reply.

OK.

As I understand there are few things wich are important for image acquisition:
1 Shuter delay time ( I have wery short  around 100 )
2 Image size ( around 1392*1040 )
3 Data transfer IEEE1394 400Mbit

Are there any other parameters wich influence aquisition?

I'm using AVT camera MARILN 145C2 Colour camera wich has up to 10 frames/second declared.

I have meassured elapsed time at SNAP function execution and it was around 500ms.

Any other information?

Best regards!

[yaHeard]

Hi danilo,

That is interesting that it is taking 500 ms since calculations show it should only take around 82 ms or so.  One way to test and see if you get the same results in grab would be to test in Measurement and Automation Explorer (MAX).  Simply do a grab and take the inverse of the fps and see if that will give you more satisfactory results.  Also test it against the results from doing a snap in MAX.

[danilo]

Hello!

In MAX it works with normal speed.
What do you think about that that I have problem with picture show in control. Do you think that this can slow down?

Regards!