  Current systems used by the Tunisian national archives for the automatic
transcription of archival documents are hindered by many issues related to the
performance of the optical character recognition (OCR) tools. Indeed, using a
classical OCR system to transcribe and index ancient Arabic documents is not a
straightforward task due to the idiosyncrasies of this category of documents,
such as noise and degradation. Thus, applying an enhancement method or a
denoising technique remains an essential prerequisite step to ease the archival
document image analysis task. The state-of-the-art methods addressing the use
of degraded document image enhancement and denoising are mainly based on
applying filters. The most common filtering techniques applied to color images
in the literature may be categorized into four approaches: scalar, marginal,
vector and hybrid. To provide a set of comprehensive guidelines on the
strengths and weaknesses of these filtering approaches, a thorough comparative
study is proposed in this article. Numerical experiments are carried out in
this study on color archival document images to show and quantify the
performance of each assessed filtering approach.
