Fisheye correction?

[1984]

Hi there,

My camera has a slight fisheye effect meaning that if I have square occupies most of the image then its sides are not straight but have a slight curve. How could I elminate this effect?

Could you help me out with some info about this? (I have the vision toolkit installed including Vision Assistant)

thanks.

(I tried to read the related articles here on the forums and now I assume that I need a dot-image for the process, but I have no idea how could I generate that.)

[GerdW]

Hi 1984,

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@1984 wrote:

Could you help me out with some info about this?

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What about this information?

[1984]

It's possible that my question was not phrased very well, so let me fix it:

Could you help me out with some info about this?

Could you help me out with instructions how to do this within the Vision Assistant?

Thanks.

[ChristopheC]

You need to acquire a grid of dots with your camera, then add an Image Calibration Step to create a new calibration.

Choose Distortion Model (Grid) for the type of Calibration to create.

Once the calibration is created, most of the Vision Assistant function will take it into account when computing their features, and return the results both in pixels and real-world coordinates.

If you need to correct the image, insert an Image Correction step.

[1984]

Ah, so you say that I need to print out a page with dots and then take a photo of it with the camera? Makes sense, although I thought there is a way to generate such thing with a tool.

Thanks!

[ChristopheC]

Correct.
Vision Development Module ships with a grid in PDF format you can print.

C:\Users\Public\Documents\National Instruments\Vision\Documentation\CalibrationGrid.pdf

Look at the Vision Assistant help for more information about calibration.