find the rotation angle for an 8bit grayscale image

[KevinKM]

Hi all,

I have an 8bit grayscale image of dimension 3969 X 600, the image is slightly tilted. i need to find the rotation angle and apply the rotation before i do the processing.

Is there any transformation functions readily available in LabVIEW to find the rotation angle?

Need your suggestions folks,

[Klemen]

Hello,

slightly tilted is a strange phrase - it doesn't tell anything about your rotation.

Do you have any characteristic points (two points at least) on your image that can be used as a reference to calculate the degree of image rotation? If you can find such fiducials, you can base your image rotation on this.

You have IMAQ Rotate readily available in the Image Manipulation pallete.

Best regards,

K

[KevinKM]

Hi Klemen,

Thanks for your time,

I am not sure which points i need to use as reference to calculate the degree of rotation, is there any functions available to calculate the rotation, I have attached the 2d array of image. I need a little more help.

Can i use the vi (rotate 8bit) which can be found in the following link below?

 http://www.ni.com/example/26943/en/

[KevinKM]

Hi Klemen,

The reference points are (0,250) (3968,359). Is there any generic formula to calculate the degree using the co-ordinates.

[Klemen · Accepted solution]

Hello,

just calculate the slope of the line, connecting both points:

xDiff = p2.x - p1.x

yDiff = p2.y - p1.y

angle [deg] = atan2(yDiff,xDiff) *(180/pi)

Best regards,

K