The precise and very fast contactless measurement of object surfaces and edges with sub-micrometer resolution plays an important role in many applications nowadays. Optical high-precision measuring devices are used for that purpose. The use of narrowband point light sources for exposing an object generates a diffraction pattern, which can be seen by a sensor. To achieve a much higher resolution than the pixel size of the detector, that additional information generated by this diffraction pattern can be used. Different algorithms for estimating the projected edge position with sub-pixel resolution using additional diffraction pattern information were evaluated. With a modelled image sensor pixel size of 3.8 mu m, results showed that a prediction error for the theoretical projected edge position on the sensor of less than 200 nm could be achieved. The influence of measurement noise, pixel size, and ADC resolution of the pixel exposure value are discussed for the presented algorithms.