• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.145-147
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• 2006

Image resizing is to change an image size by upsampling or downsampling of a digital image. Most still images and video frames are given in a compressed domain on digital media. Image resizing of a compressed image can be performed in a spatial domain via decompression or recompression. In general, resizing of a compressed image in a compressed domain is much faster than that in a spatial domain. In this paper, we propose an approach to resize images in the integer discrete cosine transform (DCT) domain, which exploits the multiplication-convolution property of DCT.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1247-1256
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• 2012

There are many filter based image processing algorithms and they usually require a huge amount of computations and memory accesses making it hard to attain a real-time performance, expecially in embedded applications. In this paper, we propose a pipelined hardware structure of the filter based face detection algorithm to show that the real time performance can be achieved by hardware design. In our design, the whole computation is divided into three pipeline stages: resizing the image (Resize), Transforming the image (ICT), and finding candidate area (Find Candidate). Each stage is optimized by considering the parallelism of the computation to reduce the number of cycles and utilizing the line memory to minimize the memory accesses. The resulting hardware uses 507 KB internal SRAM and occupies 9,039 LUTs when synthesized and configured on Xilinx Virtex5LX330 FPGA. It can operate at maximum 165MHz clock, giving the performance of 108 frame/sec, while detecting up to 20 faces.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.925-928
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• 2006

본 논문에서는 영상에 워터마크를 삽입하고 추출하는 동시에 원영상을 복원하는 리버서블 워터마킹 알고리즘을 제안한다. 제안한 알고리즘의 핵심은 워터마크가 삽입된 영상에 변하지 않는 위치정보를 전달하는 것이다. 본 논문에서는 우선 원영상을 odd image와 even image로 분리한 다음odd image에 interpolation 기법을 이용하여 resizing시키고 resizing 된 영상(odd_resize_image)에서 기수항은 그대로 두고 우수항은 기수항과 우수항의 차이값으로 채우는 방법으로 location map을 얻는다. 이 location map 에 의해 워터마크를 삽입위치를 선택하면 추출과정에서도 같은 location map을 이용할 수 있기에 워터마크 삽입위치를 정확하게 판단하여 추출할 수 있고 동시에 원본 영상을 복원할 수 있다. 본 알고리즘은 영상에 변화를 적게 주었기 때문에 높은 비가시성을 보인다. 실험 결과 $256{\times}256$ 영상에서 PSNR이 평균 53.07dB의 우수한 비가시성을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.405-407
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• 2017

The environmental change is affecting the farm products like tomato, and pepper, etc. This affects to lead smart farming yield. What is more, this inconstant conditions cause the farms to be infected by variety diseases. Therefore ICT technology is needed to detect and prevent the crops from being effected by diseases. This article suggests the procedure to help producer for identifying farms disease based on the detected image. This detects the kind of diseases with comparing the trained image data before and after disease emergence. First step monitors an image of farms and resize it. Its features are extracted on parameters such as color, and morphology, etc. The next steps are used for classification to classify the image as infected or non-infected. on the bassis of detection algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.309-311
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• 2012

본 논문에서는 3차원 입체 비디오처리 기술의 최종목표인 디지털 홀로그램을 생성하는데 필요한 정보인 객체의 좌표와 색상정보를 얻기 위해서 간단하게 장면이 정확히 일치하는 RGB image와 depth image를 생성할 수 있는 시스템을 구축하는 방법을 제안하였다. 가시광선과 적외선의 파장을 이용하여 파장에 따라 투과율이 달라지는 cold mirror를 사용하여 같은 시점에 대한 RGB + depth image를 얻은 후, 전처리 과정에서 카메라 왜곡에 대한 lens correction과정을 걸친 후, 해상도를 맞추기 위한 resolution resize과정을 마친 후, 디지털 홀로그램으로 구현 할 object를 추출한다. 그 다음 CGH(computer-generated hologram) 알고리즘으로 추출한 object를 CGH로 만든다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.83-90
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• 2008

EThe digitalized image information has various resolution, and it has been developed for several technologies to resize image depending on user's requests and applications. Recently the algorithm using edge information for good image/video quality on up-sampling was introduced, and the pre-processing procedure is required for edge extraction. Than, the predicted direction in intra prediction used in H.264/AVC has the similarity up to 80% for the edge information, so I propose the image up-sampling method using edge information. In proposed method, the image quality is similar to result of adapting n'th kernel. and the method reduces the number of calculation by about 50%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.867-880
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• 2007

We derive a modified version of cubic convolution interpolation for the enlargement or reduction of digital images by arbitrary scaling factors. The proposed scaling scheme is used to resize various format pictures in the transcoding system, which transforms the bitstream compressed at a bit rate, such as the HD bitstream, into another bit rate stream. In many applications such as the transcoder, the resolution conversion is very important for changing the image size while the scaled image maintains high quality. We focus on the modification of the scaler kernel according to the relation between formats of the original and the resized image. In the modification, various formats defined in MPEG standards are considered. We show experimental results that demonstrate the effectiveness of the proposed interpolation method.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.531-538
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• 2012

Visual cryptography is a scheme that recovers secret image through human vision by overlapping distributed share images without cryptographic operations. Distribution methods are still being developed for improving quality of shared images keeping size of images invariant and enhancing robustness against resize of images. Since visual cryptography only uses shared images, this fact is exploited to attack. From this fact, a scheme safe for sharing distributed images is needed. In this paper, a new visual cryptographic scheme using cover image is proposed. This scheme reduces the chance of detection against steganalysis and increases security. In addition, this paper shows that the proposed scheme can completely decrypt secret image without creating noise.

• Journal of Korea Multimedia Society
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• v.15 no.2
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• pp.179-194
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• 2012

Digital image forgery is becoming a topic of great interest with regard to honesty in imaging. We can often see forged digital images in a variety of places, such as the internet, and magazines, and in images used in political ads, etc. These can reduce the reliability and factual basis of the information contained in image. Therefore, objectivity is needed to determine if the image is forged so as to prevent confusion in the viewing public. Most digital forgeries consist of image resizing, rotating including the following interpolations. To find evidence of interpolation in forged images, this paper proposes a new method for detecting digital image forgery using general interpolation factors analyzed through re-interpolation algorithm of the forged images in order to determine the differences in the patterns. Through the re-interpolation algorithm we could detect the forged region and filtering region used image retouching included to interpolation.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.170-176
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• 2015

The stamp is one of the crucial information of traditional historical and cultural for nations. In this paper, we purpose to detect official stamps from scanned document and recognize the Mongolian traditional, historical stamps. Therefore we performed following steps: first, we detect official stamps from scanned document based on red-color segmentation and document standard. Then we collected 234 traditional stamp images with 6 classes and 100 official stamp images from scanned document images. Also we implemented the processing algorithms for noise removing, resize and reshape etc. Finally, we proposed a new scale invariant classification algorithm based on KNN (k-nearest neighbor). In the experimental result, our proposed a method had shown proper recognition rate.