perspective calibration

[sammy346]

I have seen the 'Perspective Calibration Example VI' and I dont understand the following....

Forgive me as I am a newbie and this may appear obvious to others....

The IMAQ Learn Calibration Template icon has no image output.  Where is the calibration information about the image saved (frame 3).

Can you confirm what is below....

To calibrate the image I must do the following....

1.  Capture an array of dots and put this into the IMAQ Learn Calibration Template VI.
2.  Use IMAQ Set Calibration Info VI on the actual image that needs to be calibrated.
3.  Do whatever geometry based vision processing that I need to (i.e. locate the coordinate of a single dot within the image).
4.  Use IMAQ Convert Pixel to Real World with the calibration information to convert to the scale that I want.

Thanks in advance

[michaeld]

Sammy,

I can understand how this example is a little misleading. The IMAQ Learn Calibration Template's output is not wired, because it is not necessary. You can consider IMAQ image type as  a wire that carries a pointer, instead of a wire that carries data. This pointer points to a location in memory where an image's information is stored (including the calibration data). Therefore, the IMAQ Learn Calibration Template VI processes the image that is passed to the input image paramater, and then consequently saves that calibration info to the same pointer. Next, in step 5, you can see that the same IMAQ image pointer (that carries the calibration info) is used as the source of the calibration data for the IMAQ Set Calibration Info.VI. The "Calibrated Image" output on the IMAQ Learn Calibration Template VI is the same pointer that is passed as an input, therefore you can use this output as the source for your calibration data. In this example, it wasn't used, because the stacked sequence was used as the source of data flow control, as opposed to the usual wiring from one block to another.