• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.68-75
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• 2006

In this paper, we propose an adaptive video watermarking method using human visual system(HVS) and characteristics of three-dimensional cosine transform (3D-DCT) cubes. We classify 3D-DCT cubes into three patterns according to the distribution of coefficients in the 3D-DCT cube: cube with motion and textures, cube with high textures and little motion, and cube with little textures and line motion. Images are also classified into three types according to the ratio of these patterns: images with motion and textures, images with high textures and little motion, and images with little textures and little motion. The proposed watermarking method adaptivelyinserts the watermark on the coefficients of the mid-range in the 3D-DCT cube using the appropriately learned sensitivity table and the proportional constants depending on the patterns of 3D-DCT cubes and types of images. Experimental results show that the proposed method achieves better performance in terms of invisibility and robustness than the previous method.

• The Journal of the Korea Contents Association
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• v.12 no.9
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• pp.1-8
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• 2012

In this paper, we propose a rate-distortion optimization method to improve the coding efficiency of the conventional 3D-DCT based compression method using adaptive block mode selection for integral images. In the conventional 3D-DCT based compression method, 3D-DCT blocks of variable block sizes are adaptively selected depending on the characteristics of integral images, and then 3D-DCT is performed. The proposed method applies a rate-distortion optimization to determine the optimal block mode. In addition, we suggest the optimal Lagrangian parameter for integral images. Experimental results show that the proposed method gives bit-rate reduction of about 5%.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.1-9
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• 2010

In this paper, we propose an efficient compression method of the integral images. The integral imaging is a well-known technique to represent and record three-dimensional images. The proposed method is based on three dimensional discrete cosine transform (3D-DCT). The 3D-DCT techniques for the integral images have been reported as an efficient coding method for the integral images which reduces the redundancies between adjacent elemental images. The proposed method is a compression method efficient to integral images using adaptive block mode(ABM), based on the 3D-DCT technique. In the ABM, 3D-DCT blocks adaptive to the characteristics of integral images are constructed, which produces variable block size 3D-DCT blocks, and then 3D-DCTs for the 3D blocks are performed. Experimental results show that the proposed method gives significant improvement in coding efficiency. Especially, at the high bit-rates, the proposed method is more excellent since the overhead incurred by the proposed method take less part of the total bits.

• Journal of Broadcast Engineering
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• v.26 no.5
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• pp.553-565
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• 2021

Point cloud is a set of points for representing a 3D object, and consists of geometric information, which is 3D coordinate information, and attribute information, which is information representing color, reflectance, and the like. In this way of expressing, it has a vast amount of data compared to 2D images. Therefore, a process of compressing the point cloud data in order to transmit the point cloud data or use it in various fields is required. Unlike color information corresponding to all 2D geometric information constituting a 2D image, a point cloud represents a point cloud including attribute information such as color in only a part of the 3D space. Therefore, separate processing of geometric information is also required. Based on these characteristics of point clouds, MPEG under ISO/IEC standardizes V-PCC, which imitates point cloud images and compresses them into 2D DCT-based 2D image compression codecs, as a compression method for high-density point cloud data. This has limitations in accurately representing 3D spatial information to proceed with compression by converting 3D point clouds to 2D, and difficulty in processing non-existent points when utilizing 3D DCT. Therefore, in this paper, we present 3D Discrete Cosine Transform-based Point Cloud Compression (3DCT PCC), a method to compress point cloud data, which is a 3D image by utilizing 3D DCT, and confirm the efficiency of 3D DCT compared to V-PCC based on 2D DCT.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.6
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• pp.127-140
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• 2003

This paper develops a novel algorithm of computing 2 Dimensional Discrete Cosine Transform (2D-DCT) via Polynomial Transform (PT) converting 2D-DCT to the sum of 1D-DCTs. In computing N${\times}$M size 2D-DCT, the conventional row-column algorithm needs 3/2NMlog$_2$(NM)-2NM＋N＋M additions and 1/2NMlog$_2$(NM) additions and 1/2NMlog$_2$(NM) multiplications, while the proposed algorithm needs 3/2NMlog$_2$M＋NMlog$_2$N-M-N/2＋2 additions and 1/2NMlog$_2$M multiplications The previous polynomial transform needs complex operations because it applies the Euler equation to DCT. Since the suggested algorithm exploits the modular regularity embedded in DCT and directly decomposes 2D DCT into the sum of ID DCTs, the suggested algorithm does not require any complex operations.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.157-160
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• 2003

In this paper. we propose a simple and effective video scene change detection algorithm using a 3-D DCT. The 3-D DCT that we employ is a 2$\times$2$\times$2 DCT has simple computations composed only of adding and shifting operations. The simple average values of multiresolution represented video using the 2$\times$2$\times$2 DCT are used as a detection feature vector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.541-548
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• 2000

In the MPEG-4 standardization phase, many methods for coding the irregular shaped VOP (video object Plane) have been researched. Texture coding is one of interesting research items in the MPEG-4. There are the Low pass extrapolation (LPE) padding, the shape adaptive DCT (SA-DCT), and the Extension-Interpolation (EI)/2D-DCT proposed in [1] as texture coding methods. the EI/2D-DCT is the method extending and interpolating luminance values from and Arbitrarily Shaped (AS) image segment into an 8 x 8 block and transforming the extended and interpolated luminance values by the 8x8 DCT. although the EI/2D-DCT and the SA-DCT work well in coding the As image segments. they are degraded since they use one-dimensional (1-D) methods such as the 1D-EI and the 1D-DCT in the two-dimensional (2-D) space. in this paper, we analyze the performance of the EI/2D-DCTand propose a new non-symmetric sig-sag scanning method, which non-symmetrically scans the quantized coefficients in the DCT domain to improve the EI/2D-DCT.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1173-1176
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• 2005

Depending on the characteristics of each 3D-DCT block, images can be classified into three types: images with motion and textures, images with high textures and little motion, images with little textures and little motion. In this paper, we propose an adaptive watermarking method using these characteristics of each 3D-DCT block. and the human visual system. The proposed method classifies patterns of 3D-DCT blocks based on the motion and texture information, and classifies the image type according to the ratio of these patterns. The watermark is inserted proportional to the 3D-DCT coefficients by using pattern adaptive JND, which. makes the proposed watermarking robust by inserting watermarks in as many blocks as possible. Experimental results show that the proposed method achieves better performance in terms of invisibility and robustness than the previous method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.3-12
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• 2005

This paper introduces a 3D perceptual model based on JND(Just Noticeable Difference) and proposes a video watermarking scheme which is perceptual approach of adaptive embedding in 3D-DCT domain. Videos are composed of consecutive frames with many similar adjacent frames. If a watermark is embedded in the period of similar frames with little motion, it can be easily noticed by human eyes. Therefore, for the transparency the watermark should be embedded into some places where motions exist and for the robustness its magnitude needs to be adjusted properly. For the transparency and the robustness, watermark based on 3D perceptual model is utilized. That is. the sensitivities from the 3D-DCT quantization are derived based on 3D perceptual model, and the sensitivities of the regions having more local motion than global motion are adjusted. Then the watermark is embedded into visually significant coefficients in proportion to the strength of motion in 3D-DCT domain. Experimental results show that the proposed scheme improves the robustness to MPEG compression and temporal attacks by about $3{\sim}9\%$, compared to the existing 3D-DCT based method. In terms of PSNR, the proposed method is similar to the existing method, but JND guarantees the transparency of watermark.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1940-1943
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• 2003

본 논문은 Polynomial 변환을 이용하여 2차원 Discrete Cosine Transform (2D-DCT)의 계산을 1차원 DCT로 변환하여 계산하는 알고리즘을 개발한다. 기존의 일반적인 알고리즘인 row-column이 N×M의 2D-DCT에서 3/2NMlog₂(NM)-2NM＋N＋M의 합과 1/2NMlog₂(NM)의 곱셈이 필요한데 비하여 본 논문에서 제시한 알고리즘은 3/2NMlog₂M ＋NMlog₂N-M-N/2＋2의 합과 1/2NMlog₂M의 곱셈 수를 필요로 한다. 기존의 polynomial 변환에 의한 2D DCT는 Euler 공식을 적용하였기 때문에 복소 연산이 필요하지만 본 논문에서 제시한 polynomial 변환은 DCT의 modular 규칙을 이용하여 2D DCT를 ID DCT의 합으로 직접 변환하므로 복소 연산이 필요하지 않다. 또한 본 논문에서 제시한 알고리즘은 각 차원에서 데이터 크기가 다른 임의 크기의 2차원 데이터 변환에도 적용할 수 있다.