• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.1-5
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• 2009

A new pixel circuit for Active Matrix Organic Light Emitting Diodes (AMOLEDs), based on the polycrystalline silicon thin film transistors (Poly-Si TFTs), was proposed and verified by SMART SPICE simulation. One driving and six switching TFTs and one storage capacitor were used to improve display image uniformity without any additional control signal line. The proposed pixel circuit compensates an inevitable threshold voltage variation of Poly-Si TFTs and also compensates the degradation of OLED at low power supply voltage($V_{DD}$). The simulation results show that the proposed pixel circuit successfully compensates the variation of OLED driving current within 0.8% compared with 20% of the conventional pixel circuit.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.47-52
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• 2016

The used digital images in the smart device and small displayer has been a downscaled image. In this paper, the detection of the downscaling image forgery is proposed using the feature vector according to the pixel value's gradients. In the proposed algorithm, AR (Autoregressive) coefficients are computed from pixel value's gradients of the image. These coefficients as the feature vectors are used in the learning of a SVM (Support Vector Machine) classification for the downscaling image forgery detector. On the performance of the proposed algorithm, it is excellent at the downscaling 90% image forgery compare to MFR (Median Filter Residual) scheme that had the same 10-Dim. feature vectors and 686-Dim. SPAM (Subtractive Pixel Adjacency Matrix) scheme. In averaging filtering ($3{\times}3$) and median filtering ($3{\times}3$) images, it has a higher detection ratio. Especially, the measured performances of all items in averaging and median filtering ($3{\times}3$), AUC (Area Under Curve) by the sensitivity and 1-specificity is approached to 1. Thus, it is confirmed that the grade evaluation of the proposed algorithm is 'Excellent (A)'.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.160-165
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• 2023

The pixel art style evolved from the shortcomings of computer image display technology has gradually transformed from a technical limitation into a widely recognized form of artistic expression since development in the early 20th century. This study analyzes the application and characteristics of the expandability of pixel art style design content in sub industries such as physical goods, environmental design, website design, digital art and illustration in the design field. It aims to explore the visual expression and sustainable development form of pixel art style under the development of new media technology that contradicts traditional technological concepts. The research results show that although the pixel art style generally pursues external visual features such as pixelated visual effects, sawtooth and matrix arrangements, its expansion in the art field shows a unique diversity of visual expressions. It has become an important means to convey nostalgic emotions and cultural values. Through this research, we hope to inspire more academic researchers and technology practitioners to explore the development potential of the pixel art style in emerging fields and promote its innovative application in design practice.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.898-901
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• 2005

We propose a novel pixel structure using bootstrapped voltage programming for amorphoussilicon TFT backplane of AM-OLED (Active Matrix-Organic Light Emitting Diode) displays. The proposed structure is composed of two TFTs and one capacitor. It operates at low drive voltage ($0{\sim}5V$) which can reduce power consumption comparing with the conventional pixel circuit structure using same OLED material. Also, it can easily control dark level and use commercial mobile LCD ICs. In this paper, we describe the operating principle and the characteristics of the proposed pixel structure and verify the performance by SPICE simulation comparing with the conventional pixel structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.5015-5038
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• 2018

In this paper, a novel spectral-spatial joint sparse representation algorithm for hyperspectral image classification is proposed based on multi-layer superpixels in various scales. Superpixels of various scales can provide complete yet redundant correlated information of the class attribute for test pixels. Therefore, we design a joint sparse model for a test pixel by sampling similar pixels from its corresponding superpixels combinations. Firstly, multi-layer superpixels are extracted on the false color image of the HSI data by principal components analysis model. Secondly, a group of discriminative sampling pixels are exploited as reconstruction matrix of test pixel which can be jointly represented by the structured dictionary and recovered sparse coefficients. Thirdly, the orthogonal matching pursuit strategy is employed for estimating sparse vector for the test pixel. In each iteration, the approximation can be computed from the dictionary and corresponding sparse vector. Finally, the class label of test pixel can be directly determined with minimum reconstruction error between the reconstruction matrix and its approximation. The advantages of this algorithm lie in the development of complete neighborhood and homogeneous pixels to share a common sparsity pattern, and it is able to achieve more flexible joint sparse coding of spectral-spatial information. Experimental results on three real hyperspectral datasets show that the proposed joint sparse model can achieve better performance than a series of excellent sparse classification methods and superpixels-based classification methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.917-924
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• 2008

Motion estimation and compensation in the spatial domain check the searching area of specified size in the previous frame and search block to minimize the difference with current block. When we check the searching area, it consumes the most encoding times due to increasing the complexity. We can solve this fault by means of motion estimation using shifting matrix in the transform domain instead of the spatial domain. We derive so the existed shifting matrix to a new recursion equation that we decrease more computations. We modify simply vertical shifting matrix and horizontal shifting matrix in the transform domain for motion estimation of half-pixel accuracy. So, we solve increasing computation due to bilinear interpolation in the spatial domain. Simulation results prove that motion estimation by the proposed algorithm in DCT-based transform domain provides higher PSNR using fewer bits than results in the spatial domain.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1809-1811
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• 1999

In recent years, attempts have been made to greatly improve the display quality of active-matrix liquid crystal display devices, and many techniques have been proposed to solve such problems as gate delay, feed-through voltage and image sticking. Gate delay is one of the biggest limiting factors for large-screen-size, high-resolution thin-film transistor liquid crystal display (TFT/LCD) design. Many driving method proposed for TFT/LCD progress. Thus we developed gate driving signal generator. Since Pixel-Design Array Simulation Tool (PDAST) can simulate the gate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the driving signals of gate lines on the pixel operations can be effectively analyzed.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.413-418
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• 2006

Highly stable thin-film transistor (TFT) pixel employing both low temperature polycrystalline silicon (LTPS) and amorphous silicon (a-Si) for active matrix organic light emitting diode (AMOLED) is discussed. ELA (excimer laser annealing) LTPS-TFT pixel should compensate $I_{OLED}$ variation caused by the non-uniformity of LTPS-TFT due to the fluctuation of excimer laser energy and amorphous silicon TFT pixel is desired to suppress the decrease of $I_{OLED}$ induced by the degradation of a-Si TFT. We discuss various compensation schemes of both LTPS and a-Si TFT employing the voltage and the current programming.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1297-1300
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• 2005

We propose a new pixel design for active matrix organic light emitting diode (AM-OLED) displays using hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs). The pixel circuit is composed of five TFTs and one capacitor, and employs only one additional control signal line. It is verified by SPICE simulation results that the proposed pixel compensates the threshold voltage shift of the a-Si:H TFTs and OLED.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.335-336
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• 2007

A new current-programmed pixel circuit for activematrix organic light emitting diodes (AMOLEDs), based on Organic TFTs (OTFTs), is proposed and verified by SPICE simulations. The simulation results show that the proposed pixel circuit, which is a current mirror structure consisting of five Organic TFTs and one capacitor, has reliable linear characteristics between input current and output OLED current. Also, the threshold voltage degradation of Organic TFTs due to long time operation stress is well compensated to reliable values.