• Journal of Multimedia Information System
• /
• v.8 no.2
• /
• pp.131-142
• /
• 2021

This paper traces the process of constructing a new one-dimensional chaotic map, and will provide a simple application in color image encryption. The use of Sarkovskii's theorem will make it possible to determine the existence of chaos and restrict all conditions to ensure the existence of this new sequence. In addition, the sensitivity to initial conditions will be proved by Lyapunov's index value. Similarly, the performance of this new chaotic map will be illustrated graphically and compared with other chaotic maps most commonly used in cryptography. Finally, a humble color image encryption application will show the power of this new chaotic map.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.4
• /
• pp.34-41
• /
• 2009

In this paper we propose a new image encryption method which utilizes Complemented MLCA(Complemented Maximum Length Cellular Automata) based on IBCA(Intermediate Boundary CA) and 2D CAT(Cellular Automata Transform). The encryption method is processed in the following order. First, Complemented MLCA is used to create a PN (pseudo noise) sequence, which matches the size of the original image. And, the original image goes through a XOR operation with the created sequence to convert the image into Complemented MLCA image. Then, the gateway value is set to produce a 2D CAT basis function. The produced basis function is multiplied by the encrypted MLCA image that has been converted to process the encipherment. Lastly, the stability analysis and PSNR(Peak Signal to Noise Ratio) verifies that the proposed method holds a high encryption quality status.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.12
• /
• pp.2693-2700
• /
• 2009

This paper proposes an effective compression method to utilize the 3D integral image with large amount of data obtained by a lens array in various applications. The conventional compression methods for still images exhibit low performance in terms of coding efficiency and visual quality, since they cannot remove the correlation between elemental images. In the moving picture compression methods, 1D scanning techniques that produce a sequence of elemental images are not enough to remove the directional correlation between elemental images. The proposed method effectively sequences the elemental images from an integral image by the 2D referencing technique and compresses them using the multi-frame referencing of H.264/AVC. The proposed 2D referencing technique selects the optimal reference image according to vertical, horizontal, and diagonal correlation between elemental images. Experimental results show that compression with the sequence of elemental images presents better coding efficiency than that of still image compression. Moreover, the proposed 2D referencing technique is superior to the 1D scanning methods in terms of the objective performance and visual quality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.104-108
• /
• 1999

It is presented many effect that represented by implicated one image more than each images with a fragment meaning. ‘Mosaic’ is technique be applied at this situation. ‘Mosaic’ is created by complicated one new image which by multi image be eliminated overlap region. This research is development for mosaic system by multi image. The system is divided that shot segmentation and mosaic image creation. Shot segmentation divided that merge with respect to similarity images which video data of moving picture in sequence time and mosaic image creation is composed of one image with which all frames in segmented shot.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.5
• /
• pp.55-62
• /
• 2011

In this paper, a temporal color and luminance variation suppression algorithm for a digital video sequence is proposed by considering time-varying light source. When a video sequence is sampled with the periodically emitting illuminant and with a short exposure time, the color rolling phenomenon occurs, where the color and the luminance of the image periodically change from field to field. In conventional signal processing techniques, the luminance variation remaining in the resultant video sequence degrades the constancy of the image sequence. In the proposed method, we obtain video sequences with constant luminance and color by compensating for the inter-field luminance variation. Based on a motion detection technique, the amount of the luminance variation for each channel is estimated on the background of the sequence without the effects of moving objects. The experimental results clearly show that our strategy efficiently estimated the illuminant change without being affected by moving objects, and the variations were efficiently reduced.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.5
• /
• pp.1019-1024
• /
• 2005

MPEG-2 achieves high compression radio, by exploiting the temporal and spatial correlations in real image sequence, using the motion compensated prediction and the transform coding, respectively. However, as the image sequence is more highly compressed, the encoded bitstream becomes more vulnerable to transmission error over the noisy channels. Furthermore, er개rs in the headers are fatal to decoding processes, because the header parameters in the video coding standard include a lot of important information connected to the syntax elements, fables, and decoding process. In this paper, we propose a new error resilience method using LSB coding for header parameters in MPEG-2 coded video transmissions. The experimental results for football and susie video sequence demonstrate that the proposed error resilience method for header parameters in MPEG-2 bitstream has good performance.

• Investigative Magnetic Resonance Imaging
• /
• v.13 no.1
• /
• pp.9-14
• /
• 2009

T1-, and T2-weighted imagings and FLAIR (fluid attenuated inversion recovery) imaging are fundamental imaging methods in the brain. T1-weighted imaging is a spin-echo sequence with short TR and short TE and produces the tissue contrast by different T1 relaxation times. In other words, short TR maximizes the difference of the longituidinal magnetization recovery between the tissues. T2-weighted imaging is a spin-echo sequence with long TR and long TE and produces the tissue contrast by different T2 relaxation times. Long TE maximizes the difference of the transverse magnetization decay between the tissues. FLAIR is an inversion recovery sequence using 180 degree inversion pulse. 2500 msec of inversion time is applied to suppress the CSF signal.

• Investigative Magnetic Resonance Imaging
• /
• v.3 no.1
• /
• pp.13-19
• /
• 1999

MRI imaging provides many benefits such as noninvasive, 3-dimensional imaging capabilities. But it has relatively serious drawback that is the long data collection time, compared with other imaging modality. Many studies have been performed for fast MR imaging. But EPI and SEPI (4-6) are required to expensive hardware. In this paper, we introduce to Burst imaging technique. It can reduce imaging time by use of a mulitple RF excitation technique. Further it is easily implemented to the normal MRI system. But a pixel profile in the conventional burst sequence is so poor that excited area by burst sequence is a small portion of a pixel. This causes poor signal to noise ratio in burst image. therefore frequency sweeping of RF pulse for burst imaging sequence is proposed to improve pixel profile. A burst pulse train is shaped by liner or nonlinear frequency sweeping function so that all the spins within a pixel are excited, thereby improving the signal to noise ratio. It also shows that the pixel profiles are dependent on how frequency sweep is made. Computer simulations with Bloch equation and experimental results obtained using a 1.0 T NMR imaging system are presented.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.8
• /
• pp.1123-1132
• /
• 2001

We show that image make converts of multiplex resolution using wavelet transform algorithm. To evaluate the robustness, we have measured comparison of similarity using various sequences which is inserted important coefficient of middle frequency band. The wavelet transform is advantage that it has a special quality of frequency domain and a special quality of spatial domain. As result of experiments, it is to certify that The chaos sequence similarity is higher than other sequence. So the chaos sequence will be used for watermark sequence.

• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.197-200
• /
• 2005

Super resolution image reconstruction method refers to image processing algorithms that produce a high resolution(HR) image from observed several low resolution(LR) images of the same scene. This method is proved to be useful in many practical cases where multiple frames of the same scene can be obtained, such as satellite imaging, video surveillance, video enhancement and restoration, digital mosaicking, and medical imaging. In this paper we applied super resolution reconstruction method in spatial domain to video sequences. Test images are adjacently sampled images from continuous video sequences and overlapped for high rate. We constructed the observation model between the HR images and LR images applied by the Maximum A Posteriori(MAP) reconstruction method that is one of the major methods in the super resolution grid construction. Based on this method, we reconstructed high resolution images from low resolution images and compared the results with those from other known interpolation methods.