Re : Keep pixel coordinates while using IMAQ Rotate?

[dpetsch]

Hello.

I would like to know if it is possible to keep the pixel coordinate information of the original image while using IMAQ Rotate.
If I assume correctly, IMAQ Rotate creates a "new" picture with "new" pixel coordinates. Thus, when looking at pixel coordinates of the rotated picture, you always get the "new" pixel coordinates. But I would like to get the pixel coordinates of the original image.

Is this possible?

Thanks for your help!

Greetings,
Dennis.

[TiTou]

Hello,

I'm not sure I understood what you mean... here is a snippet, hope this can help you.

If you mean you want the same pixel after the rotation, I think you have to calculate the coordinates "after rotation" yourself using the angle.

[dpetsch]

Hi,

---

@TiTou wrote:
Hello,

I'm not sure I understood what you mean... here is a snippet, hope this can help you.
[...]

---

thanks for the code, but unfortunately this is not what I had in mind.

---

@TiTou wrote:
[...]

If you mean you want the same pixel after the rotation, I think you have to calculate the coordinates "after rotation" yourself using the angle.

---

Yes, this is exactly what I ment. I rotate the picture, then use pattern matching to find some specific pixels in the image. From these pixels I need the pixel coordinates. But I only get the coordinates of the rotated image, not from original one.
I tried using the "Set simple calibration" to specify the rotation angle and then use "Convert Pixel to Real World", but this didn't work somehow, although it should, right?

Greetings,
Dennis

[Vladimir_Drzik]

Hi Dennis

I've made a rough example demonstrating the reverse rotation of the coordinates. Hope it helps.

Vladimir

[TiTou]

Hi Vladimir,

I'm interested in seeing your VI, could you repost it in LV 8.20 please ?

[Vladimir_Drzik]

Here it goes...

[TiTou]

Thanks a lot !

[dpetsch]

Thanks Vladimir,

it works.
But I still wonder, why my first approach won't work:

---

@dpetsch wrote:
I tried using the "Set simple calibration" to specify the rotation angle and then use "Convert Pixel to Real World", but this didn't work somehow, although it should, right?

---

Can you tell me, why this doesn't work?

Cheers,
    Dennis.

[Vladimir_Drzik]

Hi Dennis

Sorry I've never used that. Maybe you could post some more details about what exactly you are feeding into the VI, so that someone from NI can help you better.

Vladimir