How can I filter a continuous grab better?

[bradle95]

I have a a continuous grap that I am trying to find the pixel distance from two boundary points. The problem is that the boundary points that are used to find the pixel distance keep jumping due to poor filtering, even when the image itself is not moving. I have attached a screenshot of the image that I am aquiring, and I would appreciate any tips on how to further refine this type of image so that the boundary points are a bit more stationary.

[Brian_Beal]

You may want to first reduce the amount of noise from the raw picture. There could be a few reasons for this noise. One would be lighting. I've seen 60 HZ light sources provide "different" images from frame to frame. Also, you will want to reduce the gain on your camera. The lower the gain, the cleaner the image.

If you could post 2 files, that would be helpful. One would be an image that works correctly, and the other would be a different image that doesn't work correctly.

[bradle95]

Unfortunately there is no gain option on this camera, unless there is some way to adjust that in the IMAQ software. On the lighting issue, I do have an AC light source which I would assume is at 60HZ, what would you suggest for an alternative?

My problem is not that one image works correctly and one does not, it is that it is just inconsistent. I have attached two screen shots and the program that I am using to acquire the image. If you look at the distance indicator, with out any change in the what the camera is viewing, the pixel distance changes. I need this to be very constistent since I am only measuring very small strains.

[Brian_Beal]

As for the lighting, you could go to a high frequency illuminator, or an LED. I think that some improvements can be made to the processing though.

I would do some processing, then threshold this picture. You don't want to perform any functions that change the shape or size of the pixels, only their contrast levels. If you could post a file of an actual image from your camera, not a screenshot, that would be most helpful.

Also, if you want to increase your speed, you should put all of your Image Acquisition functions on the outside of your loop, except for the Grab Acquire. Put the initialization and setup functions to the left, and the close on the right. Be sure to use the Stop button, because if you abort, the Close function won't execu
te.