English: Demonstration of interlace and so-called "interline twitter", based on part of an RCA Indian Head Test Card ca. 1940. From left to right: progressive, interlace animation, and reconstructed using "bob" (interpolation per field) algorithm. Top row: original full-resolution image; bottom row: vertically blurred using [1 4 6 4 1]/16 kernel. Progressive images are darkened somewhat to match the effective brightness of the interlaced images.
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{{Information |Description={{en|Demonstration of interlace and so-called "interline twitter", based on part of an RCA Indian Head Test Card ca. 1940. From left to right: progressive, interlace animation, and reconstructed using "bob" (interpolation per fi