• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.149-156
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• 2013

This paper presents a hardware edge detector of image signal at pixel level of CMOS image sensor (CIS). The circuit detects edges of an image based on a bump circuit combining with the pixels. The APS converts light into electrical signals and the bump circuit compares the brightness between the target pixel and its neighbor pixels. Each column on CIS 64 by 64 pixels array shares a comparator. The comparator decides a peak level of the target pixel comparing with a reference voltage. The proposed edge detector is implemented using 0.18um CMOS technology. The circuit shows higher fill factor 34% and power dissipation by 0.9uW per pixel at 1.8V supply.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.977-984
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• 2019

This paper proposes a single image dehazing that utilizes the transmission estimation with low complexity and the pixel-based JBDCP (Joint Bright and Dark Channel Prior) for the effective application of hazy outdoor images. The conventional transmission estimation includes the refinement process with high computational complexity and memory requirements. We propose the transmission estimation using combination of pixel- and block-based dark channel information and it significantly reduces the complexity while preserving the edge information accurately. Moreover, it is possible to estimate the transmission reflecting the image characteristics, by obtaining a different air-light for each pixel position of the image using the pixel-based JBDCP. Experimental results on various hazy images illustrate that the proposed method exhibits excellent dehazing performance with low complexity compared to the conventional methods; thus, it can be applied in various fields including real-time devices.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1677-1683
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• 2006

Color image segmentation is useful for fast retrieval in large image database. For that purpose, new image segmentation technique based on the probability of pixel distribution in the image is proposed. Color image is first divided into R, G, and B channel images. Then, pixel distribution from each of channel image is extracted to select to which it is similar among the well known probabilistic distribution function-Weibull, Exponential, Beta, Gamma, Normal, and Uniform. We use sum of least square error to measure of the quality how well an image is fitted to distribution. That P.d.f has minimum score in relation to sum of square error is chosen. Next, each image is quantized into 4 gray levels by applying thresholds to the c.d.f of the selected distribution of each channel. Finally, three quantized images are combined into one color image to obtain final segmentation result. To show the validity of the proposed method, experiments on some images are performed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.38-48
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• 2011

Block based LCD backlight nonideality and crosstalk compensation methodologies are proposed based on the analysis of backlight profiles and image pixel homogeneity. Large computation complexity required in the conventional compensations is minimized without the degradation of image qualities by optimizing image block size, image area inside the block to be excluded from the compensation computation and the required backlight range to be computed. The optimization results of computation complexity as well as image qualities are verified for the proposed compensation by real image data simulations.

• ETRI Journal
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• v.29 no.5
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• pp.703-705
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• 2007

An image fidelity assessment using the edge histogram descriptor (EHD) of MPEG-7 is presented. Neither additional data nor fragile watermarking is needed, and there is no need to access the original image as a reference. Only the EHDs of the original image and the received image are required. The peak signal-to-noise ratio (PSNR) obtained by comparing the EHD extracted from the received image and that of the original image is used to assess the noise level of the received image. Experimental results show that the PSNRs calculated from the conventional pixel-to-pixel gray level and from the proposed bin-to-bin EHD maintain a proportional relationship. This implies that the EHD can be used instead of image data for the image fidelity assessments.

• 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 the Korea Society of Computer and Information
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• v.21 no.8
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• pp.1-12
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• 2016

In this paper, we propose a very efficient reversible data hiding algorithm using spatial locality and the surface characteristics of image. Spacial locality and a variety of surface characteristics are present in natural images. So, it is possible to precisely predict the pixel value using the locality and surface characteristics of image. Therefore, the frequency is increased significantly at the peak point of the difference histogram using the precisely predicted pixel values. Thus, it is possible to increase the amount of data to be embedded in image using the spatial locality and surface characteristics of image. By using the proposed reversible data hiding algorithm, visually high quality stego-image can be generated, the embedded data and the original cover image can be extracted without distortion from the stego-image, and the embedding data are much greater than that of the previous algorithm. The experimental results show the superiority of the proposed algorithm.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.3
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• pp.266-270
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• 2004

The image interpolation is one of an image preprocessing process to heighten a resolution. The conventional image interpolation used much to concept that it put in other pixel to select the nearest value in a pixel simply, and use much the temporal object interpolation techniques to do the image interpolation by detecting motion in a moving picture presently. In this paper, it is proposed the image interpolation techniques using the fuzzy wavelet base function. This is applied to embody a correct edge image and a natural image when expand part of the still image by applying the fuzzy wavelet base function coefficient to the conventional B-spline function. And the proposal algorithm in this paper is confirmed to improve about 1.2831 than the image applying the conventional B-spline function through the computer simulation.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.8
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• pp.35-43
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• 1992

We have presented the tracing algorithm for center pixel of character image. Character image was read by scanner device. Performing the tracing process, it can be possible to detect feature points, such as branch point, stroke of 4 directions. So, the tracing process covers the thinning and feature point detection process for improving the processing time. Usage of suggested tracing algorithm instead of thinning that is the preprocessing of character recognition increases speed up to 5 times. The preprocessing chip has been designed by using single layer perceptron algorithm.

• Proceedings of the IEEK Conference
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• 2000.11d
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• pp.77-80
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• 2000

In this paper, we present a new automatic thresholding algorithm based on maximum entropy of two-dimensional pixel histogram. While most of the previous algorithms select thresholds depending only on the histogram of gray level itself in the image, the presented algorithm considers 2D relational histogram of gray levels of two adjacent pixels in the image. Thus, the new algorithm tends to leave salient edge features on the image after thresholding. The experimental results show the good performance of the presented algorithm.