Accuracy of coordinate measurements in the case of phase modulation by digital raster

We consider the development of optoelectronic instruments used for measuring linear and angular quantities based on focal-plane arrays (photomatrices) with the help of a digital phase analyzer (digital raster). It is shown that, unlike the phase raster with mechanical drive, the digital raster guarantees the possibility of automation, increasing the accuracy of measurements, and decreasing the weight and size characteristics of the measuring instruments. We propose a method for constructing digital raster based on the use of photomatrices in combination with computer technologies. To guarantee the required accuracy of the developed optoelectronic devices, we study the sources and components of measurement errors. We analyze the influence of the discrete structure of digital raster on the measurement errors of the coordinates of image. We obtain mathematical expressions for the evaluation of the limit values of the errors of coordinate measurements caused by the parasitic phase modulation formed in the case of application of the digital raster (sampling error). The dependences of these errors on the parameters of images and pixel size are determined. It is shown that, by using the permissible maximum sampling error, it is possible to compute the required sizes of the photomatrix pixel. In this case, the size of the sampling pixel can be larger than the size of the photomatrix pixel, which is very important from the viewpoint of energy relations. The obtained results prove to be useful for the development of optoelectronic means of angular and linear measurements with digital rasters.