• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2107-2115
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• 2007

In this paper, the scan conversion processor which converts the triangle represented by three vertices into pixel-level screen coordinates, depth coordinate, and color data is designed. The processor adopts scan-line algorithm which decomposes triangle into horizontal spans and then transforms the span into pixel data. By supporting top-left filling convention, it ensures that triangles that share an edge do not produce any dropouts or overlaps between adjacent polygons. It consists of about 21,400 gates and its maximum operating frequency is about 80 Mhz under 0.35um CMOS technology. Because its maximum pixel rate is about 80 Mpixels/sec, it can be applicable to mobile graphics application.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.8
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• pp.61-66
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• 2008

Recently, portable devices which require small area and low power consumption employ applications using 3D graphics such as 3D games and 3D graphical user interfaces. We propose an efficient clipping engine algorithm which is suitable in 3D graphics pipeline. The clipping operation is divided into two steps: one is the selection process in the transformation engine and the other is the pixel clipping process in the scan conversion unit. The clipping operation is possible with addition of simple comparator. The clipping for the Y-axis is achieved in the edge walk stage and that for the X and Z-axis is performed in the span processing. The proposed clipping algorithm reduces the operation cycles and the area of of 3D graphics pipelines. We designed a 3D graphics pipeline with the proposed clipping algorithm using Verilog-HDL and verifies the operation using an FPGA.

• Korean Journal of Cognitive Science
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• v.20 no.4
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• pp.573-601
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• 2009

The present study investigated the perceptual span during reading Korean, using the moving-window display change technique introduced by McConkie and Rayner(1975). Eight different window sizes were used in Experiment 1. They were 3, 5, 7, 9, 11, 13, 15 characters in size and the full line. Reading rate, number of fixation, saccadic distance, fixation duration were compared between each window-size condition and the full line condition. The reading rate was no higher in the full line condition than in the 15 character condition but was higher than in the other conditions. The number of fixations was no larger in the full line condition than in the 15 character condition, had a tendency to be larger than in the 13 characters condition, and was more than in the other conditions. The result pattern of the saccadic distance based on character was the same as that of the reading rate, and the saccadic distance based on the pixel was the same as that of the number of fixation. Similarly, for fixation duration, there was no differences between whole line condition and 15, 13, and 11 characters condition. The fixation duration had a tendency to be shorter in the 9 characters, and was shorter in the 7, 5, and 3 characters conditions than whole line condition. In Experiment 2, based on asymmetry of perceptual span, the 6 different window sizes(0, 1, 2, 3, 4 characters in size and the full line) were used. There was a difference only between the 0 condition and the other conditions in the reading rate, number of fixations, fixation duration. Considering the pattern of eye-movement measures above, the perceptual span of Korean readers extends about 6-7 characters to the right of fixation and 1 character to the left of fixation.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.6
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• pp.25-32
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• 1994

A new projection-based approach derived from the Radon transform for detecting and estimating 3-D locations of unresolved targets in a time-sequential set of infrared imageries is presented. Since the signal-to-noise ration per pixel is very low (a dim target) and target tracks which span over many image frames. Since the 2-D multiple representations along arbitary orientations utilizing the 3-D Radon transform, our projection-based transform method enables us to analyze the 3-D problem in terms of its 2-D projections. Our method not only alleviates the great computatioonal expense of processing entire set of images as a whole, but the results reveal that the proposed strategy produces a robust detection and estimation of 3-D target trajectories event at low SNRs.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.97-104
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• 2005

Vision-based lane sensing systems require accurate and robust sensing performance in lane detection. Besides, there exists trade-off between the computational burden and processor cost, which should be considered for implementing the systems in passenger cars. In this paper, a stereo vision-based lane detection system is developed with considering sensor configuration aspects. An inverse perspective mapping method is formulated based on the relative correspondence between the left and right cameras so that the 3-dimensional road geometry can be reconstructed in a robust manner. A new monitoring model for estimating the road geometry parameters is constructed to reduce the number of the measured signals. The selection of the sensor configuration and specifications is investigated by utilizing the characteristics of standard highways. Based on the sensor configurations, it is shown that appropriate sensing region on the camera image coordinate can be determined. The proposed system is implemented on a passenger car and verified experimentally.

• Smart Structures and Systems
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• v.29 no.1
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• pp.221-235
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• 2022

Manual inspection of steel box girders on long span bridges is time-consuming and labor-intensive. The quality of inspection relies on the subjective judgements of the inspectors. This study proposes an automated approach to detect and segment cracks in high-resolution images. An end-to-end cascaded framework is proposed to first detect the existence of cracks using a deep convolutional neural network (CNN) and then segment the crack using a modified U-Net encoder-decoder architecture. A Naïve Bayes data fusion scheme is proposed to reduce the false positives and false negatives effectively. To generate the binary crack mask, first, the original images are divided into 448 × 448 overlapping image patches where these image patches are classified as cracks versus non-cracks using a deep CNN. Next, a modified U-Net is trained from scratch using only the crack patches for segmentation. A customized loss function that consists of binary cross entropy loss and the Dice loss is introduced to enhance the segmentation performance. Additionally, a Naïve Bayes fusion strategy is employed to integrate the crack score maps from different overlapping crack patches and to decide whether a pixel is crack or not. Comprehensive experiments have demonstrated that the proposed approach achieves an 81.71% mean intersection over union (mIoU) score across 5 different training/test splits, which is 7.29% higher than the baseline reference implemented with the original U-Net.

• The KIPS Transactions:PartB
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• v.15B no.5
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• pp.383-390
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• 2008

Block based transform coding is most popular approach for image and video compression. However it suffers from severe quality degradation especially from blocking artifacts. The subjective quality degradation caused by such blocking artifacts in general does not agree well with an objecive quality measurement such as PSNR. Hence new quality evaluation technique is necessary. We propose a new image quality assessment method by measuring blocking artifacts for block based transform coded images. In order to characterize blocking artifacts, proposed method utilizes the facts that, blocking artifacts, when occur, have different pixel values along the block boundaries and such differences usually continuously span along the whole boundaries. This method does not require the original uncompressed image. It operates on single block boundary and quantifies the amount of blocking artifacts on it. Experiments on various compressed images various bitrates show that proposed quantitative measure of blocking artifacts matches well with the subjective quality of them judged by human visual system.