Interlace is correctly translated as interlacing. However, the word interlace is also used for the interlacing of television lines, the interlaced process. This method was developed under the premise that the television signal is displayed flicker-free with the lowest possible refresh rate.
In the interlaced scanning process, a complete picture, a full picture, is built up from two different fields. For this purpose, only the odd lines (1, 3, 5, ..) are displayed in the first field and only the even lines (2, 4, 6, ..) in the second field. The eye integrates these short line jumps into a complete image.
If, on the other hand, scanning takes place from top to bottom in each line, i.e. continuously, this is referred to as progressive scan.resolutions and display methods are identified by letters that are appended to the number of lines or the picture repetition frequency. In the case of interlaced scanning, the letter "i" is appended to the number of lines; in the case of progressive scanning, the letter "p" is appended. Thus, 1,020i is an HDTV display with interlaced scanning and two fields, while 720p is a progressive scan with 720 lines.