• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.10
• /
• pp.4108-4125
• /
• 2015

This paper presents a scalable coding method for depth images by considering the quality of synthesized images in virtual views. First, we design a new edge detection algorithm that is based on calculating the depth difference between two neighboring pixels within the depth map. By choosing different thresholds, this algorithm generates a scalable bit stream that puts larger depth differences in front, followed by smaller depth differences. A scalable scheme is also designed for coding depth pixels through a layered sampling structure. At the receiver side, the full-resolution depth image is reconstructed from the received bits by solving a partial-differential-equation (PDE). Experimental results show that the proposed method improves the rate-distortion performance of synthesized images at virtual views and achieves better visual quality.

• Journal of the Optical Society of Korea
• /
• v.20 no.5
• /
• pp.586-592
• /
• 2016

This paper proposes a luminance compensation method using optical sensors to achieve high luminance uniformity of active matrix organic light-emitting diode (AMOLED) displays. The proposed method compensates for the non-uniformity of luminance by capturing the luminance of entire pixels and extracting the characteristic parameters. Data modulation using the extracted characteristic parameters is performed to improve luminance uniformity. In addition, memory size is optimized by selecting an optimal bit depth of the extracted characteristic parameters according to the trade-off between the required memory size and luminance uniformity. To verify the proposed compensation method with the optimized memory size, a 40-inch 1920×1080 AMOLED display with a target maximum luminance of 350 cd/m² is used. The proposed compensation method considering a 4σ range of luminance reduces luminance error from ± 38.64%, ± 36.32%, and ± 43.12% to ± 2.68%, ± 2.64%, and ± 2.76% for red, green, and blue colors, respectively. The optimal bit depth of each characteristic parameter is 6-bit and the total required memory size to achieve high luminance uniformity is 74.6 Mbits.

• Journal of Korea Multimedia Society
• /
• v.15 no.4
• /
• pp.492-500
• /
• 2012

In this paper, improved contour region coding method is proposed to accomplish better depth map coding performance. First of all, in order to use correlation between color video and depth map, a structure in SVC is applied to 3DVC. This can reduce bit-rate of the depth map while supporting the video to be transferred via various collection of network. As the depth map is mainly used to synthesize videos from different views, corrupted contour region can damage the overall quality of video. We hereby adapt a new differential quantization method when separating the contour region. The experimental results show that the proposed method can improve video quality by 0.06~0.5dB which translate the bit rate saving by 0.1~1.15%, when compared to the reference software.

• ETRI Journal
• /
• v.33 no.5
• /
• pp.695-703
• /
• 2011

The number of adders and critical paths in a multiplier block of a multiple constant multiplication based implementation of a finite impulse response (FIR) filter can be minimized through common subexpression elimination (CSE) techniques. A two-bit common subexpression (CS) can be located recursively in a noncanonic sign digit (CSD) representation of the filter coefficients. An efficient algorithm is presented in this paper to improve the elimination of a CS from the multiplier block of an FIR filter so that it can be realized with fewer adders and low logical depth as compared to the existing CSE methods in the literature. Vinod and others claimed the highest reduction in the number of logical operators (LOs) without increasing the logic depth (LD) requirement. Using the design examples given by Vinod and others, we compare the average reduction in LOs and LDs achieved by our algorithm. Our algorithm shows average LO improvements of 30.8%, 5.5%, and 22.5% with a comparative LD requirement over that of Vinod and others for three design examples. Improvement increases as the filter order increases, and for the highest filter order and lowest coefficient width, the LO improvements are 70.3%, 75.3%, and 72.2% for the three design examples.

• Journal of Broadcast Engineering
• /
• v.16 no.2
• /
• pp.339-349
• /
• 2011

IBDI (Internal Bit Depth Increase) is able to significantly improve the coding efficiency of high definition video compression by increasing the bit depth (or precision) of internal arithmetic operation. However the scheme also increases required internal memory for storing decoded reference frames and this can be significant for higher definition of video contents. So, the reference frame memory compression method is proposed to reduce such internal memory requirement. The reference memory compression is performed on 4x4 block called the processing unit to compress the decoded image using the correlation of nearby pixel values. This method has successively reduced the reference frame memory while preserving the coding efficiency of IBDI. However, additional information of each processing unit has to be stored also in internal memory, the amount of additional information could be a limitation of the effectiveness of memory compression scheme. To relax this limitation of previous memory compression scheme, we propose a selective merging-based reference frame memory compression algorithm, dramatically reducing the amount of additional information. Simulation results show that the proposed algorithm provides much smaller overhead than that of the previous algorithm while keeping the coding efficiency of IBDI.

• Tunnel and Underground Space
• /
• v.23 no.6
• /
• pp.480-492
• /
• 2013

After the introduction of geothermal power generation technology based on engineering reservoir creation that can be applied on non-volcanic region, industrial need for studies on the efficient and economic execution of costly deep-depth drilling work becomes manifest increasingly. However, since it is very difficult to predict duration and cost of boring work with acceptable reliability because of many uncertain events during the execution, efficient and organized work management for drilling is not easily achievable. Especially, the round trip that discretely occurs because of the abrasion of bit takes more time as the depth goes deeper and it has a great impact on the work performance. Therefore, a technology that can simulate the occurrence timing and depth of round trip in advance and therefore optimize them is essentially required. This study divided the abrasion state of bit into eight steps for simulation cases and developed a forecast algorithm, i.e., TOSA which can analyze the depth and timing of round trip occurrence. A methodology that can divide a unit section for simulation has been suggested; while the Bourgoyne and Young model has been used for the forecast of drilling rates and bit abrasion extent by section. Lastly, the designed algorithm has been systemized for the convenience of the user.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.633-636
• /
• 1991

This paper describes the auto depth control system for underwater vehicle that can be used for both near surface and deeply submerged depthkeeping operations. This controller uses the fuzzy control algorithm and is implemented on the 16 bit microprocessor 8086 and coprocessor 8087. For verifying this system design, the digital simulator using PC-386 based T800 transputer is proto-totyped and the real time simulations show us satisfactory results.

• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.9
• /
• pp.237-246
• /
• 2016

DIBR (Depth Image Based Rendering) is a multimedia technology that generates the virtual multi-view images using a color image and a depth image, and it is used for creating glasses-less 3-dimensional display contents. This research describes the effect of depth accuracy about the objective quality of DIBR-based multi-view images. It first evaluated the minimum depth quantization bit that enables the minimum distortion so that people cannot recognize the quality degradation. It then presented the comparative analysis of non-uniform domain-division quantization versus regular linear quantization to find out how effectively express the accuracy of the depth information in same quantization levels according to scene properties.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.1C
• /
• pp.37-47
• /
• 2011

In this paper, we propose a novel ML decoding scheme based on the combination of depth- and breadth-first search methods on a partitioned tree for multiple input multiple output systems. The proposed scheme first partitions the searching tree into several stages, each of which is then searched by a depth- or breadth-first search method, possibly exploiting the advantages of both the depth- and breadth-first search methods in an organized way. Numerical results indicate that, when the depth- and breadth-first search algorithms are adopted appropriately, the proposed scheme exhibits substantially lower computational complexity than conventional ML decoders while maintaining the ML bit error performance.

• Journal of Korea Multimedia Society
• /
• v.18 no.2
• /
• pp.149-157
• /
• 2015

The 3D-AVC standard aims at improving coding efficiency by applying new techniques for utilizing intra, inter and view predictions. 3D video scenes are rendered with existing texture video and additional depth map. The depth map comes at the expense of increased computational complexity of the encoding process. For real-time applications, reducing the complexity of 3D-AVC is very important. In this paper, we present a fast intra mode decision algorithm to reduce the complexity burden in the 3D video system. The proposed algorithm uses similarity between texture video and depth map. The best intra prediction mode of the depth map is similar to that of the corresponding texture video. The early decision algorithm can be made on the intra prediction of depth map coding by using the coded intra mode of texture video. Adaptive threshold for early termination is also proposed. Experimental results show that the proposed algorithm saves the encoding time on average 29.7% without any significant loss in terms of the bit rate or PSNR value.