Hoon-Gee Yang

Edge Adaptive Color Interpolation for Ultra-Small HD-Grade CMOS Video Sensor in Camera Phones

This paper proposes an edge adaptive color interpolation for an ultra-small HD-grade complementary metal-oxide semiconductor (CMOS) video sensor in camera phones that can process 720-p/30-fps videos. Recently, proposed methods with great image quality perceptually reconstruct the green component and then estimate the red/blue component using the reconstructed green and neighbor red and blue pixels. However, these methods require the bulky memory line buffers in order to temporally store the reconstructed green components. The edge adaptive color interpolation method uses seven or nine patterns to calculate the six edge directions. At the same time, the threshold values are adaptively adjusted by the sum of the color values of the selected pixels. This method selects the suitable one among the patterns using two flowcharts proposed in this paper, and then interpolates the missing color values. For verification, we calculated the peak-signal-to-noise-ratio (PSNR) in the test images, which were processed by the proposed algorithm, and compared the calculated PSNR of the existing methods. The proposed color interpolation is also fabricated with the 0.18-㎛ CMOS flash memory process.

A Solution to the RFID Reader Interference Problem using Adaptive Beam-forming Approach

Abstract Radio frequency identification (RFID) is one of the most attractive and futuristic technologies that can identify an object or person wirelessly, using electromagnetic radio waves. In a multiple reader RFID system, the reader interference problem is a very common phenomenon. Efforts are required to minimize this problem as performance, speed and reliability of the entire system highly depends on our ability to solve this problem efficiently. A simple adaptive beam-forming technique is proposed for solving the reader interference problem in a multiple reader RFID system. This new approach is able to effectively generate deep nulls at the direction of interference and respond to the direction of our desired signal. Simulations are carried out to evaluate the performance of our adaptive beam-forming approach and the results confirmed that, the proposed method can adaptively generate a high gain beam to the desired signal direction to acquire and track the signal completely, and it can generate deep nulls at the direction of other readers effectively to avoid interference. Moreover, this method has been found to be very efficient in terms of Bit Error Rate and energy consumption.

A new circular subarray configuration using a modified genetic algorithm

In recent times, digital beamforming with an analog-to-digital converter for a phased-array radar has attracted wide interest due to its stability and accuracy. Generally, to obtain a high gain, a phased array radar requires many antenna elements, which results in high cost and computing load. To mitigate these problems, subarraying, which divides the entire array elements into a few disjoint groups, is a good solution. In this paper, we propose a new design methodology for disjoint subarray configuration based on a modified Genetic algorithm and a new grouping rule to preserve the number of desired subarrays. The validity of the proposed algorithm is demonstrated through simulation.

Security camera based on a single chip solution using a sharply outlined display algorithm and variable-clock video encoder

In this paper, we have proposed a security camera system that displays high-definition images by using a sharply outlined display algorithm (SODA), which generates less hardware complexity because of a modified video encoder. While the proposed system uses a charge coupled device (CCD) with a complementary filter that may cause some problems in representing vivid color, we have been able to resolve the problem by mixing two signals, such as those generated by chrominance and luminance processes. In doing so, the system requires the use of a video encoder that converts the CCDs output signals into a composite video baseband signal (CVBS). Moreover, although a video encoder generally operates at 27 MHz the CCD module used in the security camera requires a particular clock frequency. Here, we have proposed that the new video encoder uses a clock to equal the CCD module at a given frequency. In doing so, the system using the encoder reduces hardware complexity and noise. The proposed system is fabricated with a test camera chip that has been manufactured by the MagnaChip 0.25 /spl mu/m CMOS process.

Phase-included simulation of UWB channel

This letter presents a method to simulate a phase-included UWB channel impulse responses for a given indoor channel. In this method we decompose a UWB pulse into a finite number of spectral components. This enables the received signal to be determined by the sum of the convolutions between each spectral component and a corresponding frequency-dependent UWB channel impulse response. The ray-tracing algorithm is applied to calculate the amplitude and the phase of each frequency-dependent channel impulse response. Based on the calculated results, we finally show the simulation of the UWB channel impulse response.

Linear Region Extension of MR Curve in ML Based Monopulse

The performance of a monopulse estimator is depend on its monopulse ratio(MR) curve. To improve its performance, a mathematical expression of the MR curve that is associated with an array the parameters is needed. In this paper, we present a novel monopulse estimator that uses the inverse function of a MR curve for the Maximum Likelihood (ML)-based monopulse estimator. It is shown that the proposed method can extend the linear region of the MR curve, which in turn improve the estimation accuracy. Moreover, it`s performance is compared with the ML-based method through simulation.

Optimization of Subarray Configurations in Linear Array Antenna Using Modified Genetic Algorithm

In this paper, we propose the optimization of subarray configurations for linear array to minimize the side lobe level (SLL) in sum beam pattern based on the genetic algorithm. The operations of genetic algorithm are modified to be applied to subarray configurations. Using the proposed method, we construct subarray structure with 16 irregular subarray elements from 40 linear array elements to minimize the SLL in sum beam pattern in case of applying the adaptive beamforming(ABF) to suppress the jamming power, whose the SLL is 10 dB lower than that of regular subarray configuration.

A Closed-Form Expression for a Maximum Likelihood Estimation-Based Monopulse Ratio Curve

The performance of a monopulse estimator depends on its monopulse ratio (MR) curve. To improve its performance, a mathematical expression of the MR curve associated with the parameters of a beamforming array is needed. In this paper, a closed-form expression for a maximum likelihood (ML) based monopulse ratio (MR) curve in a uniform linear array (ULA) monopulse radar is derived mathematically. Moreover, an approximate expression for the closed-form is presented. The validity of the closed-form derivation and its approximation is demonstrated through simulation.

M ＆ S Tool for Analyzing the Detection Performance in Bistatic Radar

This paper proposes a M & S Tool for simulating the detection performance in the bistatic radar system. After examing the interrelationship among the bistatic radar parameters, (probability of detection), (probability of false alarm) and ��SNR of the received signal, we analyze the range of the bistatic radar range product and range sum. We derive the number of integration of the received pulses that satisfies the required detection performance of the bistatic radar system, along with the analysis of the performance degradation in the jammer scenario. Finally, the analyzed results are implemented in the M & S Tool which consists of 4 modules.

A New TR-UWB Receiver Exploiting Frequency Components

This letter presents a new TR-UWB receiver exploiting frequency components of UWB pulses. This is accomplished by separating frequency-components of UWB pulses into real and imaginary parts, independently correlating and effectively combining them. We analytically show this scheme improves the output SNR compared with a conventional one using complex correlation. This will also be justified by simulation results.