scrollbar position in image display

[anne.M]

I am acquiring and displaying live images with labview 7 but without Vision. I want the scrollbar to stay fixed in a chosen position but when the images refreshes it goes back to the top left corner. Is it possible to set the position of the scrollbar for a whole sequence of acquisition ?
Thanks

[jcrooke]

What display control are you usng to display your image? That is, on which control is the scrollbar causing problems? Is it a color image? I have done live image aquisition without Vision in the past. I have displayed the image using a picture control and using an intensity graph control. Sounds to me like you are talking about the vi window's scrollbar and your image is in a display control that is larger than the vi window dimensions, or the dimensions of your monitor. Is this is the case?

I am using 6.1, but I may be able to answer your question as long as it isn't 7.0-specific.

[anne.M]

I am using image display classic from the controls panel. I set the size of the display window in order to fit with the other graphs and command displayed on the front panel. It is the scrollbars of the display window not the vi's that I want to have fixed in the position of a region of interest.
I attached a screenshot of the front panel

[Matthew C]

Anne,

Thank you for contacting National Instruments.

From what you have described, it sounds like you are interested in setting a default center position for the image in the image frame.

To accomplish this, you can create a property node for the image frame by right clicking the frame on the front panel and selecting Create >> Property Node. Right click the property node that appears on the block diagram and select Change All To Write. Expand the property node to display two elements. Use the left mouse button to click on the top element and select Image Center Position >> X Position. Click the bottom element and select Image Center Position >> Y Position. You can then wire either controls or constants to the two elements of the property n
ode to set a default center for your image.

I have included an example VI that illustrates what I have described. If this does not solve your problem or you have further questions, let me know.

Matthew C
Applications Engineer
National Instruments

[anne.M]

thank you very much, it is exactly what I needed.

I have another problem with the same vi, but it is unrelated: the acquisition of the camera is slow making the image blink. I think it is because I do the acquisition and the processing of every image in the same while loop ( is it so ? ). But I can't see how to do the two steps simultaneously but in different loops.
I attached my vi to this comment, it is made from an example I founded on this very useful web site !

[Anonymous]

Anne,

I apologize for the delayed response.

I have modified your VI to demonstrate how to run two parallel loops
(one for display and one for processing). I may not have it exactly
correct based on your preferences, but it should eliminate the
"blinking" you have been experiencing.

Best Regards,

Matthew C
Applications Engineer
National Instruments