Calibration from one deformed image to another

[Adam_H]

Hi Xavier,

Are the problems you having apparent only in the image display or do you see it in measurements you are performing on the image as well.  If it is simply in the image display you need to use the IMAQ Correct Calibrated Image.vi.  The calibration is not updated in the image display unless you use it.  In many cases it is not necessary to display the calibrated image so to help streamline have a separate function to correct displayed image.

[X.]

Now *I* don't understand what you are talking about!

I'll rephrase... I first calibrate (part of) an image by defining points in that image and telling the Calibrate VI what the "real world" coordinates of these points are. In so doing I get a "calibration" attached to an image (which is my original image, but I immediately save a copy of this calibration in a dummy image). In some part of my application, I use this calibration to indeed "correct" other images, but that's not what I am talking about here.

Here, I am only concerned in using the calibration information (saved in my dummy image) to compute the "real world" coordinates of some pixels in the original image. This is were the VI seems to fail in the sense that, whereas the coordinates seem to be somewhat adequately transformed (my green dots look arranged like they should in the "real world"), an offset is introduced.

I am not sure I understand what you are suggesting. Correcting an image and computing "real world" coordinates seem to me two different things that should not affect each other...

Kind of lost.

X.

[X.]

The smiley is not my doing, it seems to be the result of the juxtaposition of " and )

X.

[Adam_H]

Hi Xavier,

 Sorry if I was not clear. When you perform a calibration the information is stored with the image in the image wires. If you wire this to a image display this information is not taken in to account by default. In order to have the calibration shown in the image display you need to use the IMAQ Correct Calibrated Image.vi. This will correct the image display. So my question from the last post was if you were only displaying the image then this might be your problem. If you are performing measurements or something else on the image then you do not need to use the VI for the calibration to take effect.

[X.]

Hi Adam,

I would tend to agree that we are getting nowhere...

X.

[Adam_H]

Hi Xavier,

It does appear we are having communication problems.  The simplest I can put it is are you only having problems with the image calibration when you are displaying it?  If so you need to use the IMAQ Correct Calibrate Image.vi.