Earticle

가시광을 통신 반송파로 사용하는 가시광 통신(Visible light communication)은 높은 대역폭과 보안 특성으로 인해 여러 해 동안 널리 연구되어 왔다. 시중의 상보성 금속산화물반도(CMOS) 이미지 센서는 전보다 높은 해상도와 처리 속도를 지원할 수 있게 되었다. 광검출기에 기반한 가시광 통신시스템과 비교하여, CMOS 이미지 센서를 광통신 수신 기에 사용하는 가시광 통신시스템도 가능하다. 이러한 가시광 통신시스템을 광 카메라통신 시스템이라고 하며, 최근 매우 높아진 스마트폰의 활용성에 의해 스마트폰에 응용 가능한 기술로서 큰 관심을 받는 기술 중 하나이다. 여러 종 류의 광 카메라 통신이 기술적으로 가능하므로, 다양한 응용분야를 개발하기 위해서 기술적 관점에서 광 카메라 통신 을 이해하는 것이 중요하다. 본 논문에서, 최근 광 카메라통신의 특성을 분류하고 광신호원과 감지소자의 물리적 특성 을 분석한다. 변조방법, 영상획득 및 읽기모드, 그리고 최근의 응용기술 특징 등을 고려하여, 전형적인 형태의 광 카메 라통신 시스템을 분석한다. 또한, 최근 개발되고 있는 광 카메라 통신시스템의 기술적 특징을 제시한다.

Visible light communication, as a technology of using visible light as communication carrier, has been actively researched for many years because of its high bandwidth and security characteristics. Complementary metal-oxide-semiconductor (CMOS)image sensors on the market now have higher resolution and higher processing speed than before. Compared with photon detector-based visible light communication (VLC) system, a kind of VLC system uses CMOS imagesensor as the optical communication receiver. The so-called optical camera communication (OCC) system has become a hot technologyin recent years due to its potential application to smartphones. Since there are different types of OCC systems, it is important to understand the OCC systems in technical viewpoints for developing applications based on OCC. In this paper, the characteristics of recent OCC systems are classified and investigated considering physical characteristics of optical source and detection device, Typical types of OCC systems are examined considering modulation methods, imaging and readout modes, and novel applications. Attracting applications of OCC systems in development are listed.

The IEEE 802.15.7r1 Optical Wireless Communications Task Group (TG7r1), also known as the revision of the IEEE 802.15.7 Visible Light Communication standard targeting the commercial usage of visible light communication systems, is of interest in this paper. The paper is mainly concerned with Image Sensor Communications (ISC) of TG7r1; however, the major challenge facing ISC, as addressed in the Technical Consideration Document (TCD) of TG7r1, is Image Sensor Compatibility among the variety of different commercial cameras on the market. One of the most challenging but interesting compatibility requirements is the need to support the verified presence of frame rate variation. This paper proposes a novel design for 2D-sequential color code. Compared to a QR-code-based sequential transmission, the proposed design of 2D-sequential code can overcome the above challenge that it is compatible with different frame rate variations and different shutter operations, and has the ability to mitigate the rolling effect as well as the rotating effect while effectively minimizing transmission overhead. Practical implementations are demonstrated and a performance comparison is presented

We report an experimental demonstration of $4{\times}4$ multiple-input multiple-output (MIMO) wireless visible light communications (VLC) using a charge-coupled device image sensor receiver instead of a photodiode receiver. An image sensor is a kind of digital camera, which is used in most mobile devices such as smart phones or laptop computers and a promising commercial candidate for a VLC receiver. The transmission distance of the experimental result is over 10 m, enough for most indoor communication applications. We expect that the MIMO VLC technique based on image sensor receivers can be widely used with the development of high-speed image sensors.

Owing to limited energy in wireless devices power saving is very critical to prolong the lifetime of the networks. In this regard, we designed a cross-layer optimization mechanism based on power control in which source node broadcasts a Route Request Packet (RREQ) containing information such as node id, image size, end to end bit error rate (BER) and residual battery energy to its neighbor nodes to initiate a multimedia session. Each intermediate node appends its remaining battery energy, link gain, node id and average noise power to the RREQ packet. Upon receiving the RREQ packets, the sink node finds node disjoint paths and calculates the optimal power vectors for each disjoint path using cross layer optimization algorithm. Sink based cross-layer maximal minimal residual energy (MMRE) algorithm finds the number of image packets that can be sent on each path and sends the Route Reply Packet (RREP) to the source on each disjoint path which contains the information such as optimal power vector, remaining battery energy vector and number of packets that can be sent on the path by the source. Simulation results indicate that considerable energy saving can be accomplished with the proposed cross layer power control algorithm.

2012년 5월 다목적실용위성 KOMPSAT-3 발사 성공 이후, 2013년 8월 KOMPSAT-5, 2015년 3월 KOMPSAT-3A의 발사 성공으로국내는 광학, 레이더, 열적외선 센서를 통합 운영할 수 있게 되었으며, 각 센서들의 특성을 융합 활용할 수 있는 기반을 마련하였다. 단일 센서가 가지고 있는 활용의 적용 범위나 산출물 정확도에 한계점을 극복하고자 다중 센서들의 장점을 취하고 단점은 상호 보완하는 다종센서간 영상융합기술이 대두하게 되었다. 본 논문에서는 다목적실용위성 군을 활용한 영상 융합 및 고부가 산출물 생성을위한 소프트웨어(InFusion) 개발에 대하여 소개하고자 한다. 먼저 각 센서들의 특징 설명과 융합 소프트웨어 개발의 필요성에 대하여 기술하고, 개발 전과정에 대하여 상세히 설명하고자 한다. 국내외 다목적실용위성 군의 자료 활용성을 증대시키고 고부가 제품생성을 통한 국내 소프트웨어의 우수성을 알리는 계기가 되고자 한다.

Following the successful launch of KOMPSAT-3 in May 2012, KOMPSAT-5 in August 2013, and KOMPSAT-3A in March 2015 have succeeded in launching the integrated operation of optical, radar and thermal infrared sensors in Korea. We have established a foundation to utilize the characteristics of each sensors. In order to overcome limitations in the range of application and accuracy of the application of a single sensor, multi-sensor image fusion techniques have been developed which take advantage of multiple sensors and complement each other. In this paper, we introduce the development of software (InFusion) for multi-sensor image fusion and valued-added product generation using KOMPSAT series. First, we describe the characteristics of each sensor and the necessity of fusion software development, and describe the entire development process. It aims to increase the data utilization of KOMPSAT series and to inform the superiority of domestic software through creation of high value-added products.

In this paper, we propose a FACET-based feature point extraction method and an image registration method for image fusion based on multi-sensors. The most important part of image registration in image fusion is the extraction of feature points in IR and VIS images. The proposed method of extracting feature points uses the FACET-based filter in an IR image and uses Harris corner detector in a VIS image because it is difficult to find common characteristics and correlations in the IR and VIS images. The proposed method of image registration consists of 5 stages: 1) extraction of the feature points, 2) detection of correspondence points by using mutual information (MI), 3) a 2D projective transformation, 4) interpolation to integers of a pixel coordination, 5) a similar measurement by using normalized mutual information (NMI). The final outcome of the fusion image expresses a pseudo color based on hue (H), saturation (S), and intensity (I). Experimental results showed that the proposed method provides robust and accurate registration results. The expression of a pseudo color image after image fusion showed methods for enhanced target detection.

전 세계적으로 사랑받고 있는 채소인 무는 뿌리채소 중 하나로 다양한 요리에 주재료로 사용되고 있어 많은 양이 생 산되고 소비된다. 무는 또한 한국의 음식 문화에서도 중요한 역할을 하는데, 대표적인 한국의 음식 중 하나인 김치 에도 무가 사용된다. 하지만 최근 급격한 기후 변화로 인해 무가 시들음병에 쉽게 노출될 수 있는 환경이 만들어져 무의 품질과 수확량이 크게 저하되는 문제가 생기고 있다. 무 시들음병 문제를 해결하기 위한 기존의 식물 대상의 질병 식별 방식은 수집한 컬러 이미지에서 수동으로 특징을 추출했기 때문에 많은 시간과 비용을 소모했다. 하지만 최근 근적외선 센서의 개발로 인해 식물의 질병 식별을 시간적, 금전적으로 보다 효율적으로 판별할 수 있도록 발전 하였다. 본 논문에서는 다중 이미지 센서를 기반으로 무인 비행체인 드론을 사용하여 무 시들음병을 식별할 수 있는 컬러 및 근적외선 이미지에 대한 딥 러닝 프레임워크를 제안하고 비교한다. 또한 사용자가 딥 러닝 모델의 결과를 시각적으로 이해할 수 있도록 설명가능한 인공지능(XAI) 접근 방식을 사용한다. 다양한 실험에서 얻은 결과로 제안 하는 프레임워크는 정확도, 계산 복잡성 측면에서 기존 탐지 시스템에 비해 더 나은 성능을 보인다는 것을 보여주었 고, 근적외선 데이터셋은 식생 지수 계산을 통해 무 시들음병을 식별하는데 효과가 있음을 보여주었다.

Radish, loved worldwide, is one of the root vegetables and is used as a main ingredient in various dishes, so it has a lot of production and consumption. Radish is also used in kimchi, one of the most popular Korean foods. Due to rapid climate change in recent years, it can be easily exposed to the radish fusarium wilt disease, which greatly reduces the quality and yield of radishes. Traditional plant disease identification methods used to solve the Fusarium Wilt problem are time-consuming and costly because they rely on manually extracting features from collected RGB images. Recent developments in near-infrared sensors have made it possible to determine plant health more efficiently, both in time and money. In this paper, we propose and compare Deep Learning Framework for RGB and NIR(Near-infrared) images that can identify radish fusarium wilt disease using Drone, Unmanned Aerial Vehicle based on multiple image sensors. It also uses an XAI(eXplainable Artificial Intelligence) approach that allows users to visually understand the results of the Deep Learning model. As a result of the various experiments, the proposed Framework showed better performance compared to existing detection systems in terms of accuracy and computational complexity, while NIR Dataset showed that it was effective in identifying the radish fusarium wilt disease through the Vegetation index calculation.

목적 : 본 연구는 척수손상 환자들에게 압력 이미지 센서를 활용한 휠체어 방석의 압력분포 조정이 척수손 상 환자들의 주요 합병증인 욕창의 예방에 있어서 실제로 얼마나 영향을 미치는지를 알아보기 위한 후 향적 연구이다. 연구방법 : 본 연구는, 발병 기간이 1년 미만인 척수손상 환자들 132명을 대상으로 진행한 연구이다. 실험 군은 휠체어 방석 압력분포 조정 당시 본인 소유의 휠체어 방석으로 진행하여 본인에게 맞추어 압력 치 가 조정된 휠체어 방석을 계속하여 사용할 수 있는 66명의 환자로 분류하였고, 대조군은 다양한 이유로 조정된 휠체어 방석을 지속하여 사용할 수 없는 66명의 환자로 분류하였다. 모든 연구대상자는 휠체어 방석 압력분포 조정 이후 1년과 2년 뒤에 한 차례씩의 욕창 발생과 시기에 대한 조사를 진행하였으며 이 조사결과에 따른 두 군 간의 욕창 발생률과 발생 시기를 비교 분석하여 휠체어 방석의 압력분포 조 정평가가 척수손상 환자들의 욕창 예방에 미치는지 영향을 확인하였다. 자료의 모든 통계학적 유의수준 은 p < .05로 정하였다. 결과 : 실험군과 대조군 두 군 간에 욕창이 발생 된 확률의 차이 결과는 모두 유의하지는 않은 것으로 나타 났으나(p > .05), 욕창의 발생 시기에 대한 두 군 간의 비교 결과는 유의한 차이를 보여주었다(p < .05) 결론 : 한 번의 휠체어 방석의 압력분포 조정만으로는 욕창 예방효과의 지속적인 유지가 어려웠다. 하지만 시기에 맞는 유지 관리를 지속할 수 있다면 향후 척수손상 환자들의 욕창 예방 관리에 매우 좋은 방안 으로 제시될 수 있을 것이다.

Objective: This is a retrospective study to determine how much the pressure distribution adjustment of a wheelchair cushion using a pressure image sensor actually affects the prevention of pressure injury, which is a major complication in patients with a spinal cord injury. Methods: This study was conducted on 132 patients with a spinal cord injury with an onset of less than 1 year. The study group proceeded using their own wheelchair cushion when adjusting the pressure distribution of the cushion, and were classified into 66 patients who could continue to use the wheelchair cushion, the pressure of which was adjusted according to the individual. The control group was divided into 66 patients who were unable to continue to use an adjusted wheelchair cushion for various reasons. All subjects investigated the occurrence and timing of a pressure injury once every 1 and 2 years after adjusting the pressure distribution of the wheelchair cushion. According to these results, the incidence and timing of a pressure injury in the two groups were compared and analyzed to determine the effect of the adjustment of the pressure distribution of the wheelchair cushion on the prevention of pressure injury in patients with a spinal cord injury. All statistical significance levels in the data were set to p < .05. Results: Although the difference in the probability of occurrence of a pressure injury between the experiment and the control groups was insignificant (p < .05), the comparison results between the two groups on the timing of the pressure injury showed a significant difference (p < .05). Conclusion: It was difficult to continuously maintain the effect of preventing pressure injury by only adjusting the pressure distribution of the wheelchair cushion once. However, if maintenance can be continued in a timely manner, the present approach can be suggested as an extremely good method for the future prevention and management of pressure injuries in patients after a spinal cord injury.

Aiming at the problems that the luminance information is not enough and the edge information can not be preserved easily in the process of the image fusion, an effective image fusion method based on nonsubsampled contourlet transform (NSCT) and adaptive guided image filtering is proposed in this paper. Firstly the source images are decomposed by NSCT with multi-scale, multi-direction and shift-invariant properties. The fusion rule of the low-frequency subband coefficients employs the local correlation energy to improve the energy and information of the subband coefficients. To acquire good effects with edge-preserving and noise reduction, the adaptive guided image filtering is introduced to the high-frequency subband coefficients as the fusion rule for the first time, and it can make use of halo-free edge slope enhancement in the fusion process. Finally, the fused image is reconstructed by the inverse NSCT. Experimental results demonstrate that the comprehensive performances of the proposed method are improved in the fusion information, edge and luminance.

In this paper, a particular application of digital photos, remote sensing, remote shooting air moving, high-resolution and high compression of medical images required by remote shooting of JPEG2000 standard applied in the field of hardware design, production was implemented. JPEG2000 standard for image compression using the software implementation of the processing speed is very slow compared to conventional JPEG disadvantages, and also the standard of JPEG2000 DWT (Discrete wavelet transform) to improve the level of compression for image data if processing speed is a phenomenon that has degraded. In order to solve these JPEG2000 compression / decompression groups were designed and applied. In this paper, the optimal JPEG2000 compression / reservoir hardware by changing the level for still image compression, faster computation speed and quality has shown improvement.

Particle swarm optimization algorithm in solving complex functions, such as slow convergence, accuracy is not high, easily falling into local optimum problem. Based on the chaos optimization is introduced into particle swarm optimization algorithm, given the chaotic particle swarm optimization algorithm. In order to improve the image quality of CMOS image sensor, the image of the main noise source and the distortion of image analysis, this paper present the development of CMOS image sensor system based on chaos particle swarm. Computer CMOS image sensor image quality simulation, the results show that chaotic particle swarm optimization algorithm convergence performance is better than that of particle swarm optimization algorithm.

This paper presents a new noise model and its application to Bayer color filter array (CFA). We investigate the effect of various noise models. In addition, we study three possible Bayer patterns. For example, current Bayer CFA utilizes RGGB pattern. However, one may consider other color combinations such as RRGB or RGBB patterns. To prove RGGB pattern’s superiority, we investigate each pattern in various noise model and noise level. We also studied the method how to generate noisy image from noisy free image. Traditional noise models do not take into account white balance, gamma and tone correction issues. Simulation results indicate that the new noise model is more reasonable than the conventional models.

The depth information of an image is used in a variety of applications including 2D/3D conversion, multi-view extraction, modeling, depth keying, etc. There are various methods to acquire depth information, such as the method to use a stereo camera, the method to use the depth camera of flight time (TOF) method, the method to use 3D modeling software, the method to use 3D scanner and the method to use a structured light just like Microsoft's Kinect. In particular, the depth camera of TOF method measures the distance using infrared light, whereas TOF sensor depends on the sensitivity of optical light of an image sensor (CCD/CMOS). Thus, it is mandatory for the existing image sensors to get an infrared light image by bundling several pixels; these requirements generate a phenomenon to reduce the resolution of an image. This thesis proposed a measure to acquire a high-resolution image through gradual area movement while acquiring a low-resolution image through pixel bundling method. From this measure, one can obtain an effect of acquiring image information in which illumination intensity (lux) and resolution were improved without increasing the performance of an image sensor since the image resolution is not improved as resolving a low-illumination intensity (lux) in accordance with the gradual pixel bundling algorithm.

Nowadays, Geographic Information System (GIS) has been widely used in traffic control or urban planning and monitoring, thus, remote sensing images should be processed in digital form, which allows rapid integration of remote sensing analysis into a GIS. This paper discusses an image processing approach by using lifting wavelet and curvelet transform to carry out the image fusion of remote sensing photos. This approach integrates the lifting wavelet and curvelet transform to deal with the challenges in remote sensing image fusion. Experiments are carried out for testing the feasibility and compare the proposed approach with traditional wavelet manner. The experimental results show that, the correlation coefficients of primary low waveband from the proposed model are a little bit higher than the panchromatic waveband. That implies the image fusion can be performed better by the proposed model. Additionally, it was found that, the enhancement of information entropy will be improved by 7.73% and 9.84% respectively from both two experiments.

Sensitivity field distribution of the sensor in ECT system is affected by the distribution of the mixture, The "soft field" property of sensitive field bring great difficulty in image reconstruction, on the basis of analyzing capacitance tomography sensitive mechanism, by analyzing that sensor structure parameters in ECT system have influence on the uniformity of the sensitive field, this paper proposed a structural parameters optimization algorithm based on the ant colony algorithm. The algorithm first determines the parameter optimization design evaluation function, and then rapidly identifies several suboptimal paths by using particle swarm optimization and initializes the pheromones in the path, Ant colony algorithm finds the optimal solution according to the initialization pheromones and using the characteristics of rapid convergence. The experimental results show that, compared with the orthogonal algorithm, the performance of the sensor designed by using the structure parameters obtained by ant colony optimization algorithm is obviously improved, Alleviate the difficulty of data acquisition circuit design and improve the accuracy and uniformity of the sensitive field, the quality of image reconstruction is improved, the relative error of image reconstruction is reduced.

There are many shortcomings in traditional JPEG2000 image compression transmission algorithms in the wireless networks, such as, large energy consumption of resources in the network, large stress and energy consumption of the compressed image acquisition node and long transmission time, the image compression algorithm based on singular value decomposition is proposed. Block adaptive compression algorithm based on singular value decomposition is used in image compression processing, through the analysis of singular value decomposition and network energy consumption model. Meanwhile, the task of the network data processing and long-distance data transmission is assigned to different roles node to complete to balance the distribution of the network energy consumption. Finally, detailed experimental simulation have done, and the experimental results show that compared with the traditional compression algorithm (JPEG2000 image compression), the image compression algorithm based on singular value decomposition greatly alleviates the network camera key node energy consumption, and improves the speed of multimedia data transmission in wireless multimedia sensor network, and quality.

A FPGA implementation of fingerprint sensors scheme is described for removing parasitic offset image on no touch. This paper proposes an effective fingerprint identification system with 160x192 array fingerprint sensor hardware. The proposed calibration scheme initializes a fingerprint sensor LSI to eliminate the influence of offset image by the electrical characteristic difference of pixel array, which is degraded during long-time use. Each step of a fingerprint algorithm is analyzed based on FPGA. This paper designs an effective hardware scheme for using the Verilog-HDL in 160x192 pixel array. The circuit includes 3 memorys and control logic. The function is verified in RTL simulation and FPGA logic synthesis.

This paper proposes 128x8 array swipe type fingerprint sensor with a capacitive-sensing technique for image enhancement. The circuit of one pixel includes a pixel level charge-sharing and charge pump to replace an ADC. The circuit also adopts the circuit technique that improves quality of dry finger image captured with capacitive fingerprint sensor LSIs. The proper operation is validated by HSPICE for one-pixel and RTL simulation including logic synthesis for a full chip design on condition of 0.35μm typical CMOS process and 3.3V power. The layout is performed by full custom flow for one-pixel and auto P&R for a full chip. The area of a full chip is 0.161mm2 (9013μm x 1781μm) and the gate count is 303,329. The area of one-pixel is 58 x 58 μm2. Pitch is 60 μm and image resolution is 423dpi.