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All the Perl that's Practical to Extract and Report

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  • For a pet project* of mine, I needed to do some image processing/recognition from a video camera. First, I wrote the recognition algorithm with PDL, which turned out to be just a few, maybe five, lines of very dense code.

    It turned out to be very difficult to use the resulting, transformed image in the way I wanted to, because passing it from the video4linux driver (JPEG output) to perl/PDL (binary PNM is the keyword there) to SDLPerl took *a lot* longer than the actual processing.

    So I rewrote the whole thin

    • Given that I'm using a 1024x768 on 1.5Ghtz hardware, that suggests that the mechanism I'm using could just about handle your camera feed, albeit at around 100% of CPU. Granted I'm not displaying the results, but this is probably still only around an order of magnitude slower.

      Since the regex itself only costs less than 0.01 seconds, that just leaves the overhead of the capture call itself (which could itself contain a Windows internal transformation) and the non-trivial cost of packing the bytestream into Im

  • If we could create an SV which pointed at memory not managed by perl, we could create one which pointed at Imager's internal image representation, and match against that. But I don't know of a way to do that.

    Another option could be to use the getsamples() method to fetch each scanline of the image. This won't avoid the basic overhead of copying, but it will avoid the overhead of Imager's I/O abstraction.

    A final option could be XS that either used i_gsamp() or the image's internal representation to perform