The demand for fast and cost-effective access to multiple compressed data sources is imminent. An interactive link between a distant user and the compressed data is needed such that data transmission is constrained to only a small subset of the compressed data that possesses specific features of interest to the user, hence avoiding transmission and decompression of other noninteresting data sources. We present the first step toward developing this user-compressed data link. We show that oriented line features can be detected in data that are transformed, prior to being quantized and coded, using the discrete cosine transform (DCT). Our work is based on the DCT performed on block sizes of 32 x 32 pixels. The choice of this particular block size is due to proprietary constraints imposed by the specific problem we were commissioned to solve. It involves a proprietary database structure. The DCT is the basis of many established image compression standards such as the Joint Photographic Experts Group (JPEG) and the Motion Picture Experts Group (MPEG). These standards are based on block sizes of 8 x 8 pixels. We also show that the effect we report is exploitable with this more familiar block size. Theoretical proof of the DCT line-feature detector and experimental results are provided. An extension of the approach for logical inference of the existence of specific objects of interest is also outlined. When used as a feature analytical tool in conjunction with its compression role, the DCT may serve as a smart compression procedure for intelligent data archiving, abstraction, and transmission.
Aiman Albert Abdel-Malek,
John E. Hershey,
"Feature cueing in the discrete cosine transform domain," Journal of Electronic Imaging 3(1), (1 January 1994). https://doi.org/10.1117/12.165169