A method is provided for decoding an encoded point matrix image including a first set of real grid points aligned along a first axis, a second set of real grid points aligned along a second axis intersecting the first axis, and a plurality of encoded data points distributed throughout the encoded point matrix image. The apparatus comprising a cylindrical screen for submerging in a fluid, the screen having an inlet pipe for connecting to a piping system, filter members, a first end, a second and a support structure. A flow scheduler stores context thread state in the associated data structure and schedules the execution of one or more context threads.