Looking for fast way to extract pixel values

[magick]

The fastest way to extract pixels is to use an API call. Pick your favorite language and read an image then extract pixels. See http://www.imagemagick.org/script/magick-wand.php for a method. A second method on that page can process pixels in parallel on a multi-core system for even better performance.

[anthony]

If it is only one pixel, crop the read either during the read, using special read options,
http://www.imagemagick.org/Usage/files/#read_mods
or using -crop, and then output a txt: Enumerated Pixel Image

For the whole image the txt: image is a still good solution.
http://www.imagemagick.org/Usage/files/#txt

But in a larger program, or or scattered pixels using the right API interface, as mentioned by Cristy (magick) is the better solution.