Shiyuan Yang

An Automatic Image Segmentation Algorithm Based on Weighting Fuzzy C-Means Clustering

Image segmentation is an important research topic in the field of computer vision. Now the fuzzy C-Means (FCM) algorithm is one of the most frequently used clustering algorithms. Although a FCM algorithm is a clustering without supervising, the FCM arithmetic should be given the transcendent information of prototype parameter; otherwise the arithmetic will be wrong. This limits its application in image segmentation. In this paper, we develop a new theoretical approach to automatically selecting the weighting exponent in the FCM to segment the image, which is called Automatic Clustering Weighting Fuzzy C-Means Segmentation (ACWFCM). This method can reduce the disturbance of noise; get the segmentation numbers more accurately. The experimental results illustrate the effectiveness of the proposed method.

Quantization Error Reduction in the Measurement of Fourier Intensity for Phase Retrieval

The quantization error in the measurement of Fourier intensity for phase retrieval is discussed and a multispectra method is proposed to reduce this error. The Fourier modulus used for phase retrieval is usually obtained by measuring Fourier intensity with a digital device. Therefore, quantization error in the measurement of Fourier intensity leads to an error in the reconstructed object when iterative Fourier transform algorithms are used. The multispectra method uses several Fourier intensity distributions for a number of measurement ranges to generate a Fourier intensity distribution with a low quantization error. Simulations show that the multispectra method is effective in retrieving objects with real or complex distributions when the iterative hybrid input-output algorithm (HIO) is used.

An Improved Method for CT/MRI Image Fusion on Bandelets Transform Domain

People living in the information age, are more and more attention to their own lives. It is also said, social life is more important in present and future. The social life contains three fields. In this paper, we will propose a new method for adjunctive therapy in social life. Recent years, as the bandelets transform has some benefits, many scholars are interested in this field. They proposed many methods to solve different problems in different fields. In this paper, we propose a new maximum local energy method to calculate the low coefficients of images. And then adopt the sum modified laplacian method to select the high coefficients of images. Later, we compare the results with wedgelets transform. In our experiments, we take wedgelets transform, bandelets transform, and LE-wedgelets transform for comparing the results. Beside the human vision, we also compare the results by quantitative analysis. The numerical experiments state clearly that the maximum local energy is an effect way for image fusion, which can get well performance in visual effect and quantitative analysis. During 100 clinic CT/MR fusion experiments in practice, compare with previous methods, the PSNR of our method is improved respectively 5.836, 5.337, 0.035.

Underwater optical image dehazing using guided trigonometric bilateral filtering

This paper describes a novel method to enhance underwater optical images by dehazing. Scattering and color change are two major problems of distortion for underwater imaging. Scattering is caused by large suspended particles, like fog or turbid water which contains abundant particles, plankton etc. Color change corresponds to the varying degrees of attenuation encountered by light traveling in the water with different wavelengths, rendering ambient underwater environments dominated by a bluish tone. Our key contribution is to propose a fast image and video dehazing algorithm, to compensate the attenuation discrepancy along the propagation path, and to take the influence of the possible presence of an artificial lighting source into consideration. The enhanced images are characterized by reduced noised level, better exposedness of the dark regions, improved global contrast while the finest details and edges are enhance significantly. In addition, our enhancement method is comparable to higher quality than the state-of-the-art methods.

Error reduction of quantized kinoforms by means of increasing the kinoform size

There are two kinds of method that utilize the redundancy in kinoform domains for reducing the reconstruction errors of quantized kinoforms. One is the iterative-dummy area (IDA) method, which increases the kinoform size indirectly by the addition of a dummy area to the desired image. The other is the interlacing technique (IT), which increases the kinoform size directly by the interlacing of a number of subkinoforms whose sizes are the same as the desired image. We compare the error reduction of quantized kinoforms between these two methods. Simulation results show that reconstruction errors from the IT method can be reduced further and faster than those from the IDA method when the kinoform size is increased to larger than 4 x 4 times the size of the desired image.

Interlacing technique approach for the synthesis of kinoforms

An interlacing technique algorithm is proposed for the synthesis of kinoforms. The conventional iterative methods are quite powerful for optimizing kinoforms, but there is still a large reconstruction error for a quantized kinoform. We suggest the use of a number of subkinoforms interlaced together to synthesize a multikinoform for reconstructing the desired image. The idea of our interlacing technique is to increase the size of a kinoform to reduce the reconstruction error. The first subkinoform is generated from the desired image. Other subkinoforms are generated from the error images between the desired image and the image reconstructed from the previous subkinoforms. A theoretical analysis shows that the reconstruction error will be reduced as the number of subkinoforms is increased. Simulation results show that our interlacing method can reduce the reconstruction error more than do the conventional iterative methods and that the reconstructed image can be improved.

Binary phase difference diffuser: Design and application in digital holography

Design of a simple diffuser, in which the absolute value of the phase difference between the diffusers adjacent samples is constant, is considered. A condition is imposed in the design so that the diffuser is suitable for use with the iterative method based on the iterative Fourier transform algorithm for calculating a two-dimensional complex amplitude function that possesses a bandlimited and smooth spectrum. A method for effectively designing this diffuser is proposed, and its application in the field of digital holography is presented.

Proposal of Fast Implicit Level Set Scheme for Medical Image Segmentation Using the Chan and Vese Model

People living in the information age, are more and more attention to their lives. It is also said, social life is more important in present and future. The social life contains three fields. In this paper, we propose a new model for active contours to detect objects in a given medical image, in order to facilitate people to have medical treatment. The proposed method is based on techniques of piecewise constant and piecewise smooths Chan-Vese Model, semi-implicit additive operator splitting (AOS) scheme for image segmentation. Different from traditional models, our model uses the level set which are corresponding to ordinary differential equation (ODE). Our model has more improved characteristics than traditional models, such as: less sensibility of noise; unnecessary of re-initialization and high speed by the simplified ordinary differential function. Finally, we validate the proposed model by numerical synthetic and real images. The experimental results demonstrate that our model is at least two times more efficient than the widely used methods.

A novel safety light curtain system using a hemispherical mirror

Light curtain systems are used to detect intruders in various cases and places. However, it is necessary to adjust the position of the light detecting element accurately in order to receive the irradiating laser light. We propose a new type safety light curtain system that uses a hemispherical mirror and an LED in this research. A hemispherical mirror can reflect irradiating light rays surroundings of 180° in the vertical direction and 360° in the horizontal direction. When an LED is at a position that is higher than the hemispherical mirror, the LED irradiating light can be reflected by the hemispherical mirror, even if the LED is arbitrarily set up. In the case that, the light of LED is intercepted when an intruder passes between the LED and the hemispherical mirror, the output voltage of the light detecting element decreases. We can set a proper threshold voltage value of the detecting element to judge whether an intruder passes or not. Our system uses a PSOC microcomputer to judge the output voltage of the receiving element with the threshold voltage value. In addition, the LED output light is modulated by 10kHz in order to avoid the influence of the surrounding turbulence light. Our experiment succeeded to detect intruder using the proposed system without accurate light axis setting.

Proposal of a multi-frame images fusion model on dual tree complex wavelet transform domain

This paper describes a novel fusion method for multi-frame medical images based on dual tree complex wavelet transform (DTCWT). As a novel of multi-resolution analysis tool, DTCWT provides flexible multi-resolution and directional expansion for image signal. Contrary to present fusion methods, the proposed algorithm extends the traditional two inputs fusion model to multiple inputs model. We take eight input unclearly medical images as input. Estimate the decomposed coefficients through the weighted soft threshold in each image, and choose the weighted coefficients. After DTCWT reconstruction, a clear image is obtained. During abundant experiments, we evaluate the proposed method both human visual and quantitative analysis. The numerical experiments reveal that the proposed model is a new strategy for attaining image fusion with satisfactory performance.