Blokcodes

Blokcodes are a class of two-dimensional block-based codes that encode information into grids of square cells. The term is used in hobbyist and artistic contexts to describe schemes where data is represented by the color, brightness, or pattern of blocks rather than by a single printed symbol. There is no universal standard, and implementations vary in size, color depth, and error handling.

Most blokcodes consist of a data area surrounded by finder patterns and alignment markers that allow a decoder to determine orientation and scale. Each block encodes a small amount of information, with multiple blocks forming a data stream. Common schemes use grayscale or color levels to represent bits or symbols. Some designs employ error-correction blocks using simple parity or more advanced codes to recover from partial obstruction or distortion.

Decoding typically involves image capture, conversion to a grid, and mapping blocks to values. Thresholding or color clustering distinguishes blocks from background, after which the bitstream is reconstructed and validated by the error-correction data. Blokcodes are used in puzzle design, street signage, and experimental art projects, where legibility by human readers or low-quality cameras is a priority.

Variants of blokcodes range from monochrome binary grids to multilevel color grids and hybrid schemes that blend visual art with data encoding. Advantages include ease of printing, visual appeal, and robustness to partial damage; limitations include lower data density and sensitivity to lighting or perspective.

See also: QR code, Data matrix, Barcode, Visual cryptography.