Interpolated progressive-scan television display with line-crawl

Abstract

A television arrangement produces a progressively-scanned display from signals representing an image scanned by a raster having lines of even fields separated vertically by a distance 2S interlaced with the lines of odd fields. For 2:1 interlace, the lines of the odd fields are spatially separated from the adjacent lines of even fields by a distance S. The lines of signal for application to the display are generated by a spatial filter having a response in the vertical direction such that an output signal occurs for each traversal of a distance S. Thus, the number of lines is doubled in each field. The lines are generated in simultaneous pairs. A parallel-to-serial converter (PISO) converts the simultaneous signals to sequential for display by progressive scanning. The PISO may be a time compressor for use with a double-rate display or a switcher for use with a vertically-dithered display. The characteristics of the filters are selected to match the psychovisual properties of the eye for eliminating line crawl, and for reducing edge flicker and motion artifacts without excessive image degradation. Advantage is taken of the psychovisual phenomenon known as adjacent band masking.