• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.807-808
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• 2008

In H.264, sub-pel motion estimation (ME) has strong effect when coding video sequences. 1/4-pel performs better at low bitrate while 1/8-pel gives better results at high bitrate. In this paper, a variable sub-pixel motion vector resolution based on block mode motion estimation method is proposed. Experiment results show that the proposed method can take the advantage of 1/4-pel at low bitrate and 1/8-pel at high bitrate. In addition to that, time is reduced from 14% to 53% compared to KTA1.3 with 1/8-pel motion vector (MV) resolution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.34-39
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• 2006

An automated surface-strain measurement system, named ASIAS, was developed by using the image processing and stereo vision techniques in the previous studies by the corresponding author and his coworkers. This system has been upgraded mainly to improve the accuracy through image enhancement, sub-pixel measurement, surface smoothing, etc., since the first version was released. The present study has still more improved the convenience of users as well as the accuracy of measurement by processing high resolution images 8 mega pixels or more which can be easily obtained from a portable digital steal camera. It is proved that high resolution image processing greatly decreases the measurement error and gives strain data without considerable deterioration of accuracy even when the deformed grids to be measured and the master grids for camera calibration are captured together in the same image, making the whole process of strain measurement much simpler.

• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.103-114
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• 2024

The escalating demands for high-resolution satellite imagery necessitate the dissemination of geospatial data with superior accuracy.Achieving precise positioning is imperative for mitigating geometric distortions inherent in high-resolution satellite imagery. However, maintaining sub-pixel level accuracy poses significant challenges within the current technological landscape. This research introduces an approach wherein upsampling is employed on both the satellite image and ground control points (GCPs) chip, facilitating the establishment of a high-resolution satellite image precision sensor orientation. The ensuing analysis entails a comprehensive comparison of matching performance. To evaluate the proposed methodology, the Compact Advanced Satellite 500-1 (CAS500-1), boasting a resolution of 0.5 m, serves as the high-resolution satellite image. Correspondingly, GCP chips with resolutions of 0.25 m and 0.5 m are utilized for the South Korean and North Korean regions, respectively. Results from the experiment reveal that concurrent upsampling of satellite imagery and GCP chips enhances matching performance by up to 50% in comparison to the original resolution. Furthermore, the position error only improved with 2x upsampling. However,with 3x upsampling, the position error tended to increase. This study affirms that meticulous upsampling of high-resolution satellite imagery and GCP chips can yield sub-pixel-level positioning accuracy, thereby advancing the state-of-the-art in the field.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.182-184
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• 2015

We have developed a novel LED display architecture with RGGB 4sub-pixels rendering. LED light control filter algorithm is proposed in order to reduce color fringes by sub-pixel rendering which is a method of perceptual enhancement. The results show that it has 2 times higher perceptual resolution without artifacts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.2
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• pp.164-173
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• 2013

In this paper, we propose multi-frame based super resolution algorithm by using motion vector normalization and edge pattern analysis. Existing algorithms have constraints of sub-pixel motion and global translation between frames. Thus, applying of algorithms is limited. And single-frame based super resolution algorithm by using discrete wavelet transform which robust to these problems is proposed but it has another problem that quantity of information for interpolation is limited. To solve these problems, we propose motion vector normalization and edge pattern analysis for 2*2 block motion estimation. The experimental results show that the proposed algorithm has better performance than other conventional algorithms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.322-331
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• 2003

Advances of high-definition television(HDTV) and personal computers call for the mutual conversion between interlaced signal and progressive signal. Especially, deinterlacing which is known as an interlaced to progressive conversion has been recently required and investigated. In this paper, we propose new deinterlacing algorithm considering sub-pixel motion information. In order to reduce the error of motion estimation, we analyze the effect of inaccurate sub-pixel motion information and model it as zero-mean Gaussian noises added respectively to each low resolution image(field). The error caused by inaccurate motion information is reduced by determining regularization parameter according to the error of motion estimation in each channel. The validity of the proposed algorithm is demonstrated both theoretically and experimentally in this paper.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.231-233
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• 2003

Agricultural land use generally shows specific temporal characteristics of NDVI obtained from satellite data. In terms of winter wheat, a higher value compared with other land use types in May and a considerably low value in June could be discriminative features of temporal change of NDVI. In this study, the author examined methods for estimating winter wheat sown area in sub-pixel level of coarse resolution satellite data using temporal characteristics of NDVI. Application of the methods to the major grain production area in China exhibited properly a spatial distribution pattern of winter wheat sown area.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.4
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• pp.90-100
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• 1996

To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.4
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• pp.412-412
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• 1996

To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.697-698
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• 2008