Invisible Image Research Articles

Near-Infrared Aerial Crop Mark Archaeology: From its Historical Use to Current Digital Implementations

Even though most archaeologists are aware of the crop mark phenomenon and its possible archaeological nature, the information on its occurrence and specific character is, in most cases, obtained by imaging in the visible spectrum. After the Second World War, the occasional use of near-infrared (NIR) sensitive emulsions attributed this kind of invisible imaging with a great potential. However, archaeological NIR imaging always remained restricted due to several reasons not, at least, its complicated workflow and uncertain results. This article wants to delve deeper into the subject, looking at the conventional film-based approach of NIR aerial reconnaissance and its historical use in archaeological crop mark research, after which a current straightforward digital approach will be outlined. By explaining the spectral properties of plants and using examples of recently acquired NIR imagery in comparison with visible frames, it should become clear why the detection and interpretation of crop marks can benefit from low-cost digital NIR imaging in certain situations.

An ASIC implementation of a low power robust invisible watermarking processor

Digital watermarking is the process of embedding data called watermark into a multimedia object so that it can be detected or extracted later to make an assertion about the object. Several software implementations of watermarking algorithms are available, but very few attempts have been made for hardware implementation. The objective of this research paper is to implement ''low power robust invisible binary image watermarking processor'' in an Application Specific Integrated Circuit (ASIC) using Hardware Description Language (HDL). An 8-bit processor has been used since it consumes less power than other higher order bit (16-bit, 32-bit, etc.) processors. The proposed invisible watermarking algorithm is implemented in spatial domain. The proposed algorithm is prototyped (i) using XILINX FPGA (ii) using ASIC. To the best of our knowledge this is the first low power binary image watermarking processor implemented in ASIC which uses 8-bit processor with no limitation on input size. The algorithm is tested in Virtex E (xcv50e-8-cs144) Field Programmable Gate Arrays (FPGA) and implemented in an ASIC.

Invisible images can influence saccadic eye movements

Invisible images can influence saccadic eye movements

Hardware implementation of invisible image watermarking algorithm using secured binary image authentication technique

In information security, the authentication and detection of tampering and forgery are of primary concern. Data hiding or watermarking for binary images authentication is a promising approach to alleviate these concerns. Even the use of a secret static key is not secured due to various attacks. To mitigate the damage of secret key exposure, key updating signature schemes can be used. Key updating is done using a one-way function. The one-way function used in this paper is the message-digest 5 (MD5) hash function. MD5 provide a unique relationship between the input and the output hash value. An additional string of data is appended with this hash value to represent the time elapsed and hence makes the key 140-bit long, which will vary dynamically. The objective is to develop real time, reliable and secure watermarking systems, which can be achieved through hardware implementations. In this paper, we present a hardware implementation of an invisible spatial domain image watermarking algorithm with dynamic key updating for binary image. The proposed architectures were modelled, simulated and synthesised in Xilinx ISE.

A gender- and sexual orientation-dependent spatial attentional effect of invisible images

Human observers are constantly bombarded with a vast amount of information. Selective attention helps us to quickly process what is important while ignoring the irrelevant. In this study, we demonstrate that information that has not entered observers' consciousness, such as interocularly suppressed (invisible) erotic pictures, can direct the distribution of spatial attention. Furthermore, invisible erotic information can either attract or repel observers' spatial attention depending on their gender and sexual orientation. While unaware of the suppressed pictures, heterosexual males' attention was attracted to invisible female nudes, heterosexual females' attention was attracted to invisible male nudes, gay males behaved similarly to heterosexual females, and gay/bisexual females performed in-between heterosexual males and females.

Optical storage of hidden images in ultraviolet-cured polymer dispersed liquid crystals

Among the different methods used to prepare polymer dispersed liquid crystals (PDLCs), polymerization induced phase separation can be successfully exploited to obtain optical recording of high resolution holographic gratings and binary images in these materials. In this paper we report a new method that allows hidden images to be obtained in PDLCs that are not detectable by light in the visible range. The possibility of storing invisible images during the curing process will be described and discussed. The binary images obtained can be detected by illuminating them with low power UV radiation, thus opening the way to interesting applications in the field of optical storage of reserved information.

Automatic recovery of invisible image watermarks from geometrically distorted images

One method of attacking an imbedded invisible watermark is to create a derivative image that is geometrically distorted relative to the original. One attack, developed at Cambridge University, is called ‘‘StirMark.’’ 1 Image-distorting methods modify images so subtly that the changes are essentially unnoticeable to a viewer. However, their effect on invisible watermarks can be devastating, rendering them unextractable. In this paper, an automated countermeasure to image-distorting attacks will be described. Employing an unmarked copy of the original image as a reference, the possible distortion in a suspect image is first detected by the method, then measured, and finally reversed, producing a restored image approximately geometrically aligned with the original. Using a robust invisible watermarking method described previously by one of the authors to produce a watermarked image, ‘‘StirMark’’ to distort the watermarked image, and a copy of the original unmarked image for reference, the restoration method is demonstrated to be sufficient by showing successful extraction of the imbedded watermark from a restored image.

Embedding image watermarks in dc components

Both watermark structure and embedding strategy affect robustness of image watermarks. Where should watermarks be embedded in the discrete cosine transform (DCT) domain in order for the invisible image watermarks to be robust? Though many papers in the literature agree that watermarks should be embedded in perceptually significant components, dc components are explicitly excluded from watermark embedding. In this letter, a new embedding strategy for watermarking is proposed based on a quantitative analysis on the magnitudes of DCT components of host images. We argue that more robustness can be achieved if watermarks are embedded in dc components since dc components have much larger perceptual capacity than any ac components. Based on this idea, an adaptive watermarking algorithm is presented. We incorporate the feature of texture masking and luminance masking of the human visual system into watermarking. Experimental results demonstrate that the invisible watermarks embedded with the proposed watermark algorithm are very robust.

SMPTE Historical Perspective: Film and Videotape Editing: The Process of Conformation

Since videotape editing began in 1956 with the introduction of videotape recording, videomakers have tried to pattern their processes after filmmaking, where editing has become an art. Filmmakers, on the other hand, have looked obliquely toward the world of videotape, and have seen transistors, resistors, and invisible images. Now, however, the marketplace demands videotape and the editor must speak time code. This article comments on the evolution of the videotape editing process, and the way in which a merger of creativity and the new technology is becoming a reality.

A new method for noncoherent image processing by using an astigmatic system

When a point on a uniform background is observed through an astigmatic system (for instance, cylindrical lenses), the image will be a segment which is perpendicular to the cylinder. A line parallel to the cylinder would give an almost invisible image after traversing the system; on the other hand a line parallel to the astigmatic segment will give an enhanced image. By using such a simple device, spatial filtering could easily be performed by rotating the astigmatic system. This method allows one to perform optical processing, giving highly luminous images. It is thus possible to work in real-time using noncoherent light.

X-RAY STEREOSCOPIC IMAGE DISPLAY

This paper describes an X-ray three-dimensional image display apparatus based on the principle of the binocular parallax and the method of optics and electronics. It can transform invisible X-ray image into visible three-dimensional image.The X-ray source used in this work consists of two triode X-ray tubes, and a plumbicon camera with high sensibility and low lag and an image intensifier are used as TV camera system. By means of processing the electronic image, we have succesfully obtained clear and extremely low X-ray dose three-dimensional image.After a brief description of the basic principle, our emphasis is laid on the analytical method of stereoscopic depth of the three-dimensional image and method of processing of how to get a stereoscopic image.The apparatus is very valuable for practical use in research works on physics, biology and medicine.

2-5 不可視光線用撮像デバイス

2-5 不可視光線用撮像デバイス

An Efficient Image Watermarking System Based on Error Correcting Codes in DCT Domain

Digital watermarking has drawn extensive attention for copyright protection of multimedia data. This paper proposes a new watermarking system for digital images using efficient systematic linear block codes (SLBC) in discrete cosine transform (DCT) domain. The proposed watermarking system using SLBC generates a code sequence of {0, 1} that provides error correction capabilities and then replaces it with a binary watermark sequence of {-1, 1}. This achieves more robust invisible image watermarks and requires a small storage unit for binary sequence numbers. The generated watermark sequence is then used as an input for our proposed watermarking system which consists of watermark embedding process and watermark detection process. Experimental results indicate that the invisible watermark embedded with the proposed system are very robust against various kinds of attacks such as white Gaussian noise, JPEG compression, median, and mean filtering, by showing similarity values ranging from 0.7 to 0.8. KEY WORDS: Digital Watermarking; Linear Block Code; Copyright Protection. DOI: http://dx.doi.org/10.3329/mist.v3i0.8056

Electrical Discharge Figures

MR. A. W. PORTER gave in NATURE of March 31 (vol. lxxxiii., p. 142) an account of his experiments on electric discharges over photographic plates, made in order to ascertain what is due to the luminosity of the discharge and what to the discharge itself. Knowing that the disruptive discharge carries metallic particles from the electrodes, and that in the silvering of mirrors by the wet processes the silver begins to set at every metallic particle which clings to the surface of the glass because of the action of local couples, I ventured to develop the invisible image of the discharge on a clean glass plate by the silvering solution.