Jae-Sik Sohn

Fast Auto-Focus Control Algorithm Using the VCM Hysteresis Compensation in the Mobile Phone Camera

A practical real-time auto-focus algorithm for a digital camera is presented in this paper, and it improves the reliability and speed of the auto-focus process, especially suitable for a 2 mega-pixel high definition camera. The proposed algorithm divides auto-focusing process into several modes and finds the focus by the different control current in the each mode. Additionally, an adaptive step size searching and a hysteresis compensation of the voice coil motor increased searching speed. The experimental result shows the proposed algorithm is faster auto-focusing than conventional algorithm in the VCM camera system

Image Adaptive Watermarking Technique for Digital Phone

Digital watermarking has been proposed as a solution to the problem of copyright protection of digital images in digital phone camera. There are two important issues that watermarking algorithms need to address. First, watermarking schemes are required to provide trustworthy evidence for protecting rightful ownership. Second, good watermarking schemes should satisfy the requirement of robustness and resist distortions due to common image manipulations. This paper presents a blind image watermarking scheme for camera phone. This method is based on singular value decomposition (SVD) and wavelet decomposition. Analysis and experimental results show that the proposed watermarking method performs well in security and robustness of digital phone camera

The Watermarking for 3D CAD Drawing using Line, ARC, 3DFACE Components

Currently there has been much interested in developing the watermarking for 3D graphic data of mesh model or NURBS. However, the watermarking technique based on 3D CAD drawing leaves something to be desired. This paper proposes a watermarking technique for 3D design drawing using the components of Line, 3DFACE and ARC based on vertex that prevent the infringement of copyright from unlawfulness reproductions and distribution. By experimental result, we confirmed the invisibility of embedded watermarks as well as the robustness in geometrical attacks and file conversion to DWG, DXF, DWT and DWS

Blind Image Watermarking Technique for Digital Phone Camera

In todays modern world, digital phone cameras are common daily gadgets that most people have and use. In the event of a traffic accident, a fire accident, or a criminal act, anyone will be able to capture these important moments and use authentic photographs for evidence purposes. Digital watermarking is able to ensure that the digital photographs taken are authentic and indeed taken from a particular phone camera. This paper presents a blind image watermarking technique for digital phone camera. This method is based on singular value decomposition (SVD) and wavelet decomposition. Experimental results show that the proposed technique performs well in security and robustness against JPEG compression.