• Journal of Korea Multimedia Society
• /
• v.3 no.4
• /
• pp.380-388
• /
• 2000

In computing the optical flow, Horn and Schunck's method which is a representative algorithm is based on differentiation. Therefore it is difficult to estimate the velocity for a large displacement by this algorithm. In this paper, we propose a method for estimating nonuniform motion from sequential images which is based on integral brightness constancy constraints. The equations which transform a source image to a target image are expressed as a function of the displacement field. If marginal effects can be neglected, the form of the transformation integral transform or orthogonal expansion can be determined from the expansion coefficients of the two images. The apparent displacement field is then computed iteratively by a projection method which utilities the functional derivatives of the linearized moment equations. We demonstrate that the performance of the orthogonal function transform on the data set of large motion.

• The KIPS Transactions:PartB
• /
• v.13B no.2 s.105
• /
• pp.83-88
• /
• 2006

Digital image processing algorithm was proposed to measure the area inside of an object image using angle-distance graph used to analyze the pattern of an object in the digital image processing techniques. The first angle-distance graph is generated from a point inside of an object area. The second angle-distance graphs are generated for the areas missed in the first graph by extracting the positions with large gradient in the first angle-distance graph. The order of the graph increases according to the complexity of an object pattern. Size of the area inside of an object boundary is measured by integrating square of distance multiplied by angle for each area from the hierarchical angie-distance graphs.

• Journal of Internet of Things and Convergence
• /
• v.10 no.2
• /
• pp.51-60
• /
• 2024

Aiming at the problem of low contrast and difficult to recognize video images in low-light environment, we propose an adaptive contrast compensation enhancement algorithm based on human visual perception. First of all, the video image characteristic factors in low-light environment are extracted: AL (average luminance), ABWF (average bandwidth factor), and the mathematical model of human visual CRC(contrast resolution compensation) is established according to the difference of the original image's grayscale/chromaticity level, and the proportion of the three primary colors of the true color is compensated by the integral, respectively. Then, when the degree of compensation is lower than the bright vision precisely distinguishable difference, the compensation threshold is set to linearly compensate the bright vision to the full bandwidth. Finally, the automatic optimization model of the compensation ratio coefficient is established by combining the subjective image quality evaluation and the image characteristic factor. The experimental test results show that the video image adaptive enhancement algorithm has good enhancement effect, good real-time performance, can effectively mine the dark vision information, and can be widely used in different scenes.

• Journal of Biomedical Engineering Research
• /
• v.25 no.4
• /
• pp.243-251
• /
• 2004

This study was to quantitative analysis compare to dynamic characteristic change of the regional cerebral blood volume (rCBV) after development of cerebral fat embolism in cats using perfusion MR Imaging. Forty-four adult rats were used. Triolein (n = 15), oleic acid (n = 9) and linoleic acid (n = 11) were injected into the internal carotid artery using microcatheter through the transfemoral approach. Polyvinyl alcohol (Ivalon) (n = 9) was injected as a control group. Perfusion MR images were obtained at 30 minutes and 2 hours after embolization, based on T2 and diffusion-weighted images. The data was time-to-signal intensity curve and ΔR$_2$＊ curve were obtained continuously with the aid of home-maid image proc in.leased significantly at 2 hours compared with those of 30 minutes (P＜0.005). In conclusion, cerebral blood flow decreased in cerebral fat embolism immediately after embolization and recovered remarkably in time course. It is thought that clinically informations to dynamic characteristic change of the cerebral hemodynamics to the early finding in cerebral infarction by DWI and PWI

• Journal of IKEEE
• /
• v.17 no.4
• /
• pp.469-477
• /
• 2013

This paper enhances the speed of a pedestrian detection using an estimation of feature information based on integral image. Pedestrian model or input image should be resized to the size of various pedestrians. In case that the size of pedestrian model would be changed, pedestrian models with respect to the size of pedestrians should be required. Reducing the size of pedestrian model, however, deteriorates the quality of the model information. Since various features according to the size of pedestrian models should be extracted, repetitive feature extractions spend the most time in overall process of pedestrian detection. In order to enhance the processing time of feature extraction, this paper proposes the fast extraction of pedestrian features based on the estimate of integral image. The efficiency of the proposed method is evaluated by comparative experiments with the Channel Feature and Adaboost training using INRIA person dataset.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.47 no.1
• /
• pp.160-170
• /
• 2010

This paper proposes a Haar Wavelet Feature Detector (HWFD) based on the Haar wavelet transform and average box filter. By decomposing the original image using the Haar wavelet transform, the proposed detector obtains the variance information of the image, making it possible to extract more distinctive features from the original image. For detection of interest points that represent the regions whose variance is the highest among their neighbor regions, we apply the average box filter to evaluate the local variance information and use the integral image technique for fast computation. Due to utilization of the Haar wavelet transform and the average box filter, the proposed detector is robust to illumination change, scale change, and rotation of the image. Experimental results show that even though the proposed method detects fewer interest points, it achieves higher repeatability, higher efficiency and higher matching accuracy compared with the DoG detector and Harris corner detector.

• Journal of Korea Multimedia Society
• /
• v.16 no.4
• /
• pp.483-492
• /
• 2013

SURF is an algorithm which extracts feature points and generates their descriptors from input images, and it is being used for many applications such as object recognition, tracking, and constructing panorama pictures. Although SURF is known to be robust to changes of scale, rotation, and view points, it is hard to implement it in real time due to its complex and repetitive computations. Using 3.3 GHz Pentium, in our experiment, it takes 240ms to extract feature points and create descriptors in a VGA image containing about 1,000 feature points, which means that software implementation cannot meet the real time requirement, especially in embedded systems. In this paper, we present a hardware architecture that can compute the SURF algorithm very fast while consuming minimum hardware resources. Two key concepts of our architecture are parallelism (for repetitive computations) and efficient line memory usage (obtained by analyzing memory access patterns). As a result of FPGA synthesis using Xilinx Virtex5LX330, it occupies 101,348 LUTs and 1,367 KB on-chip memory, giving performance of 30 frames per second at 100 MHz clock.

• Journal of Korea Multimedia Society
• /
• v.13 no.11
• /
• pp.1621-1629
• /
• 2010

This paper presents an improved fast MSRCR algorithm that MSRs are commonly adopted at tone mapping in color vision. Conventional MSRs consist of three SSRs, which use three Gaussian functions with different scales as those surround ones. This convolution processes require much computation load. Therefore, the proposed algorithm adopts a hierarchical discrete correlation which is equivalent to Gaussian function and the Retinex process is only applied to the luminance channel in order to get a fast processing. A simple color preservation scheme is applied to the Retinex output from the luminance channel in the proposed MSRCR algorithm. Experimental results show that the proposed algorithm required less number of oprations and computation time about 1/9.5 and 1/3.5 times, respectively, than those of the simplest MSR and was equivalent to conventional MSRs.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.10
• /
• pp.1244-1251
• /
• 1988

Edge is one of the primitive features of an image and is widely used in image classification and analysis. New edge extration methods using central moments are presented and show various characteristics according to the order of moment, definition of both random variables and probability density functions. The proposed methods use the integral of differences between local mean and pixels in the window whereas most of conventional edge operators use only differential concepts. This gives good noise immunity and extracts fine edges.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.8
• /
• pp.707-716
• /
• 2013

Tire noise is divided into two parts. One is pattern noise the other one is road noise. Pattern noise primarily occurs in over 500 Hz frequency but road noise occurs mainly in low frequency. It is important to develop a technology to predict the pattern noise at the design stage. Prediction technology of pattern noise has been developed by using image processing. Shape of tire pattern is computed by using imaging signal processing. Its results are different with the measured one. Therefore, the prediction of actual measured pattern noise is valuable. In the signal processing theory is applied to calculate the impulse response for the measurement environment. This impulse response used for the prediction of pattern noise by convolving this impulse response by the results of image processing of tire pattern.