More Pixels Equals Better Measurements
With video or digital imaging systems the general rule is more pixels equals more precision. By using very high-resolution digital cameras for inspection such as the 8 mega-pixel sensor on the Sentry, one can view larger parts in one image and still make precise measurements. The continuing improvements in the size of mega-pixel cameras translates to better and better measurement performance for this class of instrument.

A Fine Eye for Detail
Sub-pixel edge detection allows the image processing software to actually interpolate between neighboring pixels to very accurately determine a feature location. For parts with sharp clean edges, this can give a 10x improvement in measurement precision over the native resolution of the CCD. As an example for a 100mm long part with clean edges the Sentry can measure any feature on it to a precision of 3 microns.

Speed and Value
Another advantage of the large format approach is one no longer needs a multi-axis measurement stage. Translation stages are not only expensive to make, but introduce a substantial amount of error into the measurement as well. The large format digital camera approach means that the part is simply placed under the lens and a picture is snapped. This takes less than a second, and avoids the extra time, expense, and error associated with a CNC moving stage.

The Magic is in the Lens
Visicon offers the largest available range of telecentric lenses for Large Format Digital inspection. Telecentric lenses have near zero optical field and perspective distortions. Also, the telecentric aperture can be set to provide absolutely amazing depths-of-field so that the part can be in-focus from top to bottom and all measurements can accurately be made from a single image.