• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.71-75
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• 2019

This paper proposes the extension of the dynamic range in complementary metal oxide semiconductor (CMOS) image sensors (CIS) using switching operation of in-pixel inverter. A CMOS inverter is integrated in each unit pixel of the proposed CIS for switching operations. The n+/p-substrate photodiode junction capacitances are added to each unit pixel. When the output voltage of the photodiode is less than half of the power supply voltage of the CMOS inverter, the output voltage of the CMOS inverter changes from 0 V to the power supply voltage. Hence, the output voltage of the CMOS inverter is adjusted by changing the supply voltage of the CMOS inverter. Thus, the switching point is adjusted according to light intensity when the supply voltage of the CMOS inverter changes. Switching operations are then performed because the CMOS inverter is integrated with in each unit pixel. The proposed CIS is composed of a pixel array, multiplexers, shift registers, and biasing circuits. The size of the proposed pixel is $10{\mu}m{\times}10{\mu}m$. The number of pixels is $150(H){\times}220(V)$. The proposed CIS was fabricated using a $0.18{\mu}m$ 1-poly 6-metal CMOS standard process and its characteristics were experimentally analyzed.

• Journal of Korea Multimedia Society
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• v.11 no.3
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• pp.292-300
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• 2008

An algorithm for detecting a line segment in an image is presented using incremental pixel extension. We use a different approach from conventional algorithms, such as the Hough transform approach and the line segment grouping approach. The Canny edge is calculated and an arbitrary point is selected among the edge elements. After the arbitrary point is selected, a base line approximating the line segment is calculated and edge pixels within an arbitrary radius are selected. A weighted value is assigned to each edge pixel, which is selected by using the error of the distance and the direction between the pixel and the base line. A line segment is extracted by Jilting a line using the weighted least square method after determining whether selected pixels are linked or delinked using the sum comparison of the weights. The proposed algorithm is compared with two other methods and results show that our algorithm is faster and can detect the real line segment.

• Journal of Sensor Science and Technology
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• v.22 no.4
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• pp.256-261
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• 2013

This paper presents an extension of the dynamic range in a complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) using a stacked photodiode and feedback structure. The proposed APS is composed of two additional MOSFETs and stacked P+/N-well/P-sub photodiodes as compared with a conventional APS. Using the proposed technique, the sensor can improve the spectral response and dynamic range. The spectral response is improved using an additional stacked P+/N-well photodiode, and the dynamic range is increased using the feedback structure. Although the size of the pixel is slightly larger than that of a conventional three-transistor APS, control of the dynamic range is much easier than that of the conventional methods using the feedback structure. The simulation and measurement results for the proposed APS demonstrate a wide dynamic range feature. The maximum dynamic range of the proposed sensor is greater than 103 dB. The designed circuit is fabricated by the $0.35-{\mu}m$ 2-poly 4-metal standard CMOS process, and its characteristics are evaluated.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.452-454
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• 2000

In recent years, the Thin Film Transistor Liquid Crystal Display (TFT-LCD) is used in a variety of products as an interfacing device between human and them. Since TFT-LCDs have trend toward larger Panel sizes and higher spatial and/or gray-scale resolution, pixel charging characteristic is very important for the large panel size and high resolution TFT-LCD pixel characteristics. In this paper, both data line precharging method and line time extension (LiTEX) method is applied to Pixel Design Array Simulation Tool (PDAST) and the pixel charging characteristics of TFT-LCD array were simulated, which were compared with the results calculated by both PDAST In which the conventional device model of a-Si TFTs and gate step method is implemented.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.39-44
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• 2009

Local Binary Pattern (LBP) is becoming a popular tool for various machine vision applications such as face recognition, classification and background subtraction. In this paper, we propose a new extension of LBP, called the Diagonal LBP (DLBP), to handle the image-based gender classification problem arise in interactive display systems. Instead of comparing neighbor pixels with the center pixel, DLBP generates codes by comparing a neighbor pixel with the diagonal pixel (the neighbor pixel in the opposite side). It can reduce by half the code length of LBP and consequently, can improve the computation complexity. The Support Vector Machine is utilized as the gender classifier, and the texture profile based on DLBP is adopted as the feature vector. Experimental results revealed that our approach based on the diagonal LPB is very efficient and can be utilized in various real-time pattern classification applications.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1247-1250
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• 2006

A new liquid crystal display (LCD) Data identified Time Extension (DiTEX) driving scheme with a high charged voltage is proposed. The different charged voltage owing to the differential charging time and various initial pixel-potential can be eliminated or diminished under this method. It is compatible with a 2-row inversion and can be realized into the commercial dual-sided gate circuits.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.413-419
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• 2012

A dynamic range extension technique is proposed based on a 3-transistor active pixel sensor (APS) with gate/body-tied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector using a feedback structure. The new APS consists of a pseudo 3-transistor APS and an additional gate/body-tied PMOSFET-type photodetector, and to extend the dynamic range, an NMOSFET switch is proposed. An additional detector and an NMOSFET switch are integrated into the APS to provide negative feedback. The proposed APS and pseudo 3-transistor APS were designed and fabricated using a $0.35-{\mu}m$ 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) process. Afterwards, their optical responses were measured and characterized. Although the proposed pixel size increased in comparison with the pseudo 3-transistor APS, the proposed pixel had a significantly extended dynamic range of 98 dB compared to a pseudo 3-transistor APS, which had a dynamic range of 28 dB. We present a proposed pixel that can be switched between two operating modes depending on the transfer gate voltage. The proposed pixel can be switched between two operating modes depending on the transfer gate voltage: normal mode and WDR mode. We also present an imaging system using the proposed APS.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.447-453
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• 2015

Increase of national family income improved demand of high-quality and year-round horticultural products including chrysanthemum. To meet these demand, farmers have introduced protected facilities, such as greenhouses, of which environmental conditions could be monitored and controlled. Environment management up to three weeks after transplanting is critical for chrysanthemum quality. Artificial lighting and light-blocking screen are especially important for long-day (day period > 13 hours) and short-day (night period > 13 hours) treatments. In this study, a web-camera was installed, and the image was obtained and transmitted to mobile phones to monitor the status of 3-wavelength(RGB) lighting environments. RGB pixel values were used to determine malfunctioning of the lighting lamps, and leaking out and incoming illumination status during short-day and long-day treatment periods. Normal lighting lamps provided RGB pixel values of 240~255. During long-day treatment period, G pixel values were useful to detect abnormal lighting conditions (e.g., leaking). During short-day treatment period, R pixel values were useful to determine incoming light (e.g., sun-light). Results of this study would provide useful information for remote monitoring of light conditions for protected chrysanthemum production under artificial lights.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.285-290
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• 2010

In this paper, a dynamic range(DR) extension technique based on a 3-transistor active pixel sensor(APS) and dual image sampling is proposed. The feature of the proposed APS is that the APS uses two or more photodiodes with different sensitivities, such as a high-sensitivity photodiode and a low-sensitivity photodiode. Compared with previously proposed wide DR(WDR) APS, the proposed approach has several advantages, such as no-external equipments or signal processing, no-additional time-requirement for additional charge accumulation, simple operation and adjustable DR extension by controlling parasitic capacitance and sensitivity of two photodiodes. Approximately 16 dB of DR extension was evaluated from the simulation for the situation of 10 times of sensitivity difference and the same size of parasitic capacitance between those two photodiodes.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.406-415
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• 2021

The worldwide spread of the Internet and the digital information revolution have resulted in a rapid increase in the use and transmission of multimedia information due to the rapid development of communication technologies. It is important to protect images in order to prevent problems such as piracy and illegal distribution. To solve this problem, I propose a new digital color image encryption algorithm in this paper. I design a new pseudo-random number generator based on 1D five-neighborhood maximum length cellular automata (FN-MLCA) to change the pixel values of the plain image into unpredictable values. And then I use a 3D chaotic cat map to effectively shuffle the positions of the image pixel. In this paper, I propose a method to construct a new MLCA by modeling 1D FN-MLCA. This result is an extension of 1D 3-neighborhood CA and shows that more 1D MLCAs can be synthesized. The safety of the proposed algorithm is verified through various statistical analyses.