Most Significant Bit Research Articles

High confidence visual recognition of persons by a test of statistical independence

A method for rapid visual recognition of personal identity is described, based on the failure of a statistical test of independence. The most unique phenotypic feature visible in a person's face is the detailed texture of each eye's iris. The visible texture of a person's in a real-time video image is encoded into a compact sequence of multi-scale quadrature 2-D Gabor wavelet coefficients, whose most-significant bits comprise a 256-byte iris code. Statistical decision theory generates identification decisions from Exclusive-OR comparisons of complete codes at the rate of 4000 per second, including calculation of decision confidence levels. The distributions observed empirically in such comparisons imply a theoretical cross-over error rate of one in 131000 when a decision criterion is adopted that would equalize the false accept and false reject error rates. In the typical recognition case, given the mean observed degree of code agreement, the decision confidence levels correspond formally to a conditional false accept probability of one in about 10/sup 31/. >

An 8-b 800-MHz DAC

An 8-b video DAC which performs conversions at 800 MHz is reported. A double poly-Si emitter self-aligned process and a 64-b MSB (most significant bit) range are used. A multiple-level emitter-coupled logic MEL decoder circuit and multiplexed data inputs are used to enhance the speed and to lower the glitch impulse. Rise and fall times are less than 380 ps for high-speed operation. Power dissipation is 750 mW with a -4.5-V supply voltage.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Systolic architectures for the computation of the discrete Hartley and the discrete cosine transforms based on prime factor decomposition

Two-dimensional systolic array implementations for computing the discrete Hartley transform (DHT) and the discrete cosine transform (DCT) when the transform size N is decomposable into mutually prime factors are proposed. The existing two-dimensional formulations for DHT and DCT are modified, and the corresponding algorithms are mapped into two-dimensional systolic arrays. The resulting architecture is fully pipelined with no control units. The hardware design is based on bit serial left to right MSB (most significant bit) to LSB (least significant bit) binary arithmetic. >

Fast multiplication without carry-propagate addition

Conventional schemes for fast multiplication accumulate the partial products in redundant form (carry-save or signed-digit) and convert the result to conventional representation in the last step. This step requires a carry-propagate adder which is comparatively slow and occupies a significant area of the chip in a VLSI implementation. A report is presented on a multiplication scheme (left-to-right, carry-free, LRCF) that does not require this carry-propagate step. The LRCF scheme performs the multiplication most-significant bit first and produces a conventional sign-and-magnitude product (most significant n bits) by means of an on-the-fly conversion. The resulting implementation is fast and regular and is very well suited for VLSI. The LRCF scheme for general radix r and a radix-4 signed-digit implementation are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A cascade comparator ADC using a magnetic modulator

The precise ampere-turn comparator can be used as a most-significant bit digital-to-analog converter (DAC) and as an input comparator in the cascade comparator analog-to-digital converter (ADC). A 20-bit cascade comparator ADC can be easily constructed using a precise ampere-turn comparator, a low-cost IC-type DAC and a low-cost IC-type ADC. This paper explains the basic system and results of various experiments on a 20-bit cascade comparator ADC by the use of a second-harmonic-type magnetic modulator.

Dynamic keep-alive to improve plasma-panel write and sustain margins

Keep-alive border cells are used to prime addressed cells of a plasma panel to improve the write margin. Currently, the time relationship between the drive waveform for the keep-alive border and the write waveform is kept fixed or static. The effectiveness of the static keep-alive arrangement is very limited: e.g., an experiment is described showing that across a 2.4-in span (between keep-alive border and address cell), this breakdown voltage increases by 14 percent and the ionization time almost doubles. These spatial variations greatly reduce the operating margins. A dynamic keep-alive scheme has been designed to provide spatial uniformity of breakdown voltage and ionization time, and thus to improve the write margins. It can be implemented by simply using the most-significant bits of an address to control the firing of a single keep-alive driver. Experimental results show that for a 5 × 5-in panel, the dynamic keep-alive scheme provides about 50-percent improvement in write margin over the static keep-alive arrangement. Some of this write margin can be traded to provide increased sustain margins.

Biologische Untersuchungen über Schutzstoffe

The least-significant-bit (LSB) technique is one of the commonly used steganographic algorithms in the spatial domain. In most existing schemes, they didn’t carefully analyze the relationship between the image content itself. Hence, the smooth areas in the cover image will inevitably be contaminated after hiding even at a low embedding rate, thereby leading to poor visual quality and low security. In recent years, diverse steganography methods using edge detection have been proposed. However, their schemes employ certain pixels in the cover image for the sake of storing edge information, resulting in significant embedding distortion and low payload. In this study, a novel steganography approach based on the combination of LSB substitution mechanism and edge detection is proposed. To avoid the excavation of human visual system (HVS) when more secret bits are embedded into pixels, we classify the cover pixels into edge areas and non-edge areas. Then, pixels that belong to the edge area are used to carry more secret bits. In addition, to further increase the payload as well as preserve good image quality, we adopt a skillful way that the edge information is determined by most significant bits (MSBs) of the cover image so that it does not need to be stored. In the extraction phase, the same edge information is obtained. Therefore, the secret data can be correctly extracted without confusion. The experimental results demonstrate that our scheme achieves a much higher payload and better visual quality than those of state-of-the-art schemes.