Security printing is the use of variable data printing (VDP) to add readable information to printed regions. This is used for brand identification, track and trace, product authentication, and, if applicable, for investigation and evidentiary purposes. Well-crafted, multiregion deterrents can be a powerful means to simultaneously provide readable information and deter would-be counterfeiters through the crafting of difficult-to-reproduce printing effects. This allows the brand owner to select the best printing technology for the deterrents (or for different aspects of a multiregion deterrent), and to gain insight into how the counterfeiter may attempt to reproduce their deterrent with a different printing approach. In this article, repeated line patterns, two-dimensional (2D) bar code reading, and authentication of a color deterrent (color tile) are considered. These features are printed using thermal ink jet (TIJ), dry electrophotography (DEP), and liquid electrophotography (LEP) digital printers. Line patterns and 2D bar code differences are representative of the printer's binary print quality. Color tiles are representative of the printer's ability to produce color-based deterrents with fidelity, and are also used to show authentication accuracy on multiple printers and on multiple substrates. Authentication of TIJ printed color tiles is better on glossy paper than on plain office paper, whereas the opposite was observed for DEP printed color tiles. Finally, meaningful metrics for comparison are discussed, including security payload density, deterrent reproducibility, color and spatial frequency fidelity, deterrent precompensation, and the sensitivity of deterrent authentication to image capture settings and devices.

Textile ink jet printing as a new dyeing method with higher resolution, lower pollution, and shorter run length has attracted more and more people's attention. Pigment inks have become one of the main colorant materials in this technology for their excellent light fastness and their suitability to all sorts of textiles. However, most organic pigments of low polarity are hard to wet and disperse in aqueous media, therefore the organic pigments must be modified before their application. In this research, waterborne nanoscale pigment dispersion including Copper Phthalocyanine blue (P.B.15:3), Quinacridone Red pigment (P.R.122), and Monoazo Yellow pigment (P.Y.14) have been prepared by the phase separation method and by the method of direct milling with dispersants, respectively. The properties (stability, particle size, and apparent viscosity) of dispersions prepared by the different methods were compared. The results show that the pigment dispersion has higher stability to alcohols, temperature, and storage, and also lower viscosity; the phase separation method was more suitable to preparation of pigment dispersion for formulations of ink jet inks than the method of direct milling with dispersants; TEM images indicated that the pigment particles were uniformly distributed in aqueous media, and the x-ray diffraction spectra indicated that the pigment crystal structure was unchanged after encapsulation in the phase separation method.

A new method is proposed for correcting the ac component of the color registration error in the paper feeding direction in a tandem-type color laser printer. The main factor of the ac color registration error is the fluctuation of the angular velocity of organic photoconductive drums caused by gears with runout in multiple gear systems. In order to express the fluctuation mathematically, the kinematical relation between a pair of gears with runout is constructed and it is extended into a multiple gear system. Also, the specific reduction ratio in the multiple gear system is proposed as a necessary condition for the correction of the ac color registration error. With the ac color registration error obtained by integrating the angular velocity, the optimization problem is formulated in terms of the installation phase of the gears with runout. A continuous evolutionary algorithm is used to find the optimal installation phases.

This article proposes a stereo vision based digital watermarking scheme that uses regularized feature-based disparity estimation for copyright protection of stereo content. The watermark data are embedded into the right image of a stereo image using the discrete wavelet transform algorithm, and a disparity vector is extracted from the left and watermarked right images. The disparity vector and the left image are then transmitted to the recipient through a communication channel. At the receiver, the watermarked right image is reconstructed from the received left image and disparity vector by employing regularized feature-based disparity estimation. From the difference between the watermarked and original right images, the embedded watermark image can then be extracted. From experiments using the stereo image pair of "Fichier," "Tunnel," and watermark data of "3D," it was found that the peak signal to noise ratio (PSNR) of the reconstructed right image through the proposed algorithm can be improved by an average of 3.61 dB compared to those of a conventional algorithm. At the same time, the PSNR of the watermark image extracted from this reconstructed right image can also be improved by an average of 2.36 dB when the Quantizer Scale is given as 20.

In this paper, digital magnification of three-dimensional (3D) imaging, using an ABMA intermediate view reconstruction (IVR) based on an adaptive block matching algorithm is proposed. The number of the elemental images obtained from a one-step pickup process can be computationally increased through the use of the proposed IVR without the need for mechanical movement and a long multistep pickup process. To show the feasibility of the proposed magnified 3D imaging system, using test images of a car, bottle, phone, and watch, it was shown that the proposed ABMA algorithm improves the peak signal to noise ratio of reconstructed intermediate images by as much as 5.16 dB on average in comparison with a conventional block and feature-based algorithm.

In this study the authors propose an endoscopic image enhancement technique named dynamic band imaging (DBI) which temporally changes the color conversion matrix. DBI is based on the estimation of multispectral band images to enhance the endoscopic color images in order to distinguish the slight color difference of early stage cancer more clearly. Since this method can be implemented by using only a software approach, it is easy to upgrade the devices, whereas the narrow band technique requires hardware upgrading. From the results of fundamental analysis by subjective evaluations, the effectiveness of DBI for image enhancement in comparison with the typical still image evaluation is demonstrated. In addition the authors have developed a user interface to determine the six required parameters of this method easily. By using this device, appropriate parameters for practical endoscopic diagnosis have been obtained. DBI is found to be a new, effective method to enhance color endoscopic images.

A simplified simulation method coupling two-dimensional (2D) and three-dimensional (3D) models is proposed for analysis of primary toner transfer processes. In the 2D model, the electric potential distribution of a vicinity of a transfer nip is simulated including conditions and configurations of the transfer process. Meanwhile, the motion of toner particles is simulated with a 3D parallel plate model, including the relation between the electric potential of the intermediate transfer belt and the transfer gap obtained by the 2D simulation. The validity of the 2D and the 3D models is separately examined, and analyses of a primary transfer process in a printer have been demonstrated using the coupling method. The method has nicely reproduced transfer phenomena with small computational load.

This study aims to clarify the factors behind the readability of paper documents; the clarification is intended to yield good guidelines for realizing truly readable Electronic Paper. Proofreading tasks were conducted under various reading conditions; display area was varied from 1/2 page to 4 pages on the screens. Proofreading performance is shown to increase with the number of pages simultaneously provided. This result agrees with our general impression that it is difficult to complete proofreading tasks on computer screens, which usually provide less than one page. The disadvantages of small display areas were confirmed regardless of the subjects' ages. Helpful guidelines for designing readable Electronic Paper were suggested by our study.