STEMMER IMAGING

Geometric correction and image de-warping

Image distortion can be caused by many factors such as lens distortion (see the optics section), or when the camera views a target at an angle to the image plane. Geometric correction is very processor intensive, but can be essential in some applications to obtain a usable image.

The two following images show the effect of placing the camera at an angle to the target, resulting in the squared grid becoming a diamond shape. Notice the original shadowing. In the right image the distortion is corrected by software.

Right image: Original image viewed at an angle to the horizontal Left image: The same image, de-warped

The next image shows the distorted effect when a label attached to a cylindrical container needs to be inspected. The label is first de-warped in software, simplifying the demand on the inspection using OCR.

This image shows the distorted effect when a label attached to a cylindrical container needs to be inspected. The label is first de-warped in software, simplifying the demand on the inspection using OCR.

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Learn more about:

• Image arithmetic and flat-field correction
• Look-up tables (LUT)
• Thresholding
• Filtering
• Morphological functions
• 2D calibration
• Colour space conversion