Sungjoo Suh

Fast scene change detection for personal video recorder

We propose an efficient scene change detection method for personal video recorder to provide users with several convenient functionalities such as the browsing, fast forward and skip-play of recorded videos. Since most of the current available PVRs have low-powered CPUs, the scene change detector should not be computationally expensive. We implement the scene change detection algorithm using reduced images of only intra pictures in MPEG-2 compressed domain. The experimental results with a commercial PVR demonstrate the efficiency of the proposed method.

Printer and scanner forensics

Contrary to popular opinion, the use of paper in our society will not disappear during the foreseeable future. In fact, paper use continues to grow rather than decline. It is certainly true that as individuals, we may be printing less than we used to. And the role of paper has been transformed from the archival record of a document to a convenient and aesthetically appealing graphical user interface. The use of paper is now intimately linked to the electronic systems that capture, process, transmit, generate, and reproduce textual and graphic content. Paper can be thought of as an interface between humans and the digital world. If this interface is not secure, the entire system becomes vulnerable to attack and abuse. Although paper is read by humans in the same way that it has been for millennia and has had the same fundamental form and composition for almost that long, the technologies for printing and scanning documents and capturing their content have evolved tremendously, especially during the last 20 years. This has moved the capability to generate printed documents from the hands of a select few to anyone with access to low-cost scanners, printers, and personal computers. It has greatly broadened the opportunities for abuse of trust through the generation of fallacious documents and the tampering with existing documents, including the embedding of messages in these documents.

Information embedding and extraction for electrophotographic printing processes

In todays digital world securing different forms of content is very important in terms of protecting copyright and verifying authenticity. One example is watermarking of digital audio and images. We believe that a marking scheme analogous to digital watermarking but for documents is very important. In this paper we describe the use of laser amplitude modulation in electrophotographic printers to embed information in a text document. In particular we describe an embedding and detection process which allows the embedding of 1 bit in a single line of text. For a typical 12 point document, 33 bits can be embedded per page.

Efficient image down-conversion for mixed field/frame-mode macroblocks

An efficient image resizing algorithm in the compressed domain with mixed field/frame-mode macroblocks is proposed. A 16/spl times/16 field/frame-mode macroblock is converted into an 8/spl times/8 reduced block in the discrete cosine transform (DCT) domain using a modified inverse DCT (IDGT) kernel which performs stronger lowpass filtering than the simple truncation in the DCT domain. Experimental results show that the proposed algorithm provides the resized image quality similar to an existing method with significantly lower computational complexity.

INFORMATION EMBEDDING AND EXTRACTION THROUGH EXPOSURE MODULATION FOR ELECTROPHOTOGRAPHIC TEXT DOCUMENTS

Abstract Printer identification based on printed documents can provide forensic information to protect copyright and verify authenticity. In addition to intrinsic features (intrinsic signatures) of the printer, modulating the printing process to embed specific signature (extrinsic signatures) will further extend the encoding capacity. In this paper we describe the use of laser modulation in electrophotographic printers to embed information in a text document. In particular we describe an embedding and detection process which allows the embedding of 1 bit in a single line of text. For a typical 12 point document with 50 lines of text, 33 bits can be embedded per page.