多声道立体声系统的声像处理

目前进入实用阶段的多声道立体声都属环绕声系统，并且其主要功能也都是为影视图像伴音。当然，也有不伴随图像的情形，例如，音乐的三维声场效果，就属此种情形。环绕声系统的主要特征是可以产生出伴随图像效果的声像，可营造出的声像效果有以下几种。（１）稳定的中置声...

职业院校教师图片及声像处理能力的提升研究

本文阐述了职业院校教师图片及声像处理能力的重要性,对职业院校教师图片和声像处理能力的现状作了分析,同时提出如何提升职业院校教师的图片和声像处理能力。

MPEG-2声像传输处理中时间延迟的高精度测量技术

时间延迟是声像传输处理中一项重要的评测指标。该文讨论了两种在MPEG-2声像节目的传输处理过程中时间延迟的高精度测量技术:针对模拟信号的测量;针对数字信号的测量。这两种测量方法对其它类似应用的测量具有一定的借鉴价值。

多声道环绕立体声电视节目的录制技巧

在大屏幕、高清晰度电视全面普及的今天,多声道环绕立体声渐渐成为电视节目发展的必然趋势。如何在现有单声道电视节目录制技术的基础上尽快过渡到环绕立体声录音,已经成为了电视节目制作的一个重要课题。本文主要对电视台日常新闻访谈类和舞台综艺类电视节目的多声道环绕声拾音方法和后期声像处理等问题进行探讨。

戏曲电视节目的现场扩声与录制

介绍了戏曲电视节目现场乐队伴奏的拾音和扩声中需要注意的几个方面。

Suppression of Speckle in SAR Images Using Wavelet-Based HMM

In order to suppress the speckle appearing in synthesis aperture radar (SAR) images, a novel speckle reduction method based on wavelet domain hidden Markov tree (HMT) was proposed. First, the image was logarithmic transformed to change the statistical property of the speckles. Then an HMT was constructed in the correspondent wavelet domain. Based on this model, the image signal was restored by maximum likelihood estimation and speckle noise was suppressed. Simulating SAR images had shown that the performance of the filter is satisfactory for both speckle smoothing and edges presentation, and for generating visually natural images as well.

Underwater Terrain-Aided Navigation Based on Multibeam Bathymetric Sonar Images

Underwater terrain-aided navigation is used to complement the traditional inertial navigation employed by autonomous underwater vehicles during lengthy missions. It can provide fixed estimations by matching real-time depth data with a digital terrain map, This study presents the concept of using image processing techniques in the underwater terrain matching process. A traditional gray-scale histogram of an image is enriched by incorporation with spatial information in pixels. Edge comer pixels are then defined and used to construct an edge comer histogram, which employs as a template to scan the digital terrain map and estimate the fixes of the vehicle by searching the correlation peak. Simulations are performed to investigate the robustness of the proposed method, particularly in relation to its sensitivity to background noise, the scale of real-time images, and the travel direction of the vehicle. At an image resolution of 1 m2/pixel, the accuracy of localization is more than 10 meters.

REDUCING PERIODIC NOISE USING SOFT MORPHOLOGY FILTER

A novel spatial domain method--soft morphology filter is presented for reducing the periodic noise in image processing. The simulation results are presented to demonstrate the effectiveness of the method in comparison with a frequency domain method and other spatial domain filters.

Interactive Genetic Algorithms with Fitness Adjustment

Noises widely exist in interactive genetic algorithms. However, there is no effective method to solve this problem up to now. There are two kinds of noises, one is the noise existing in visual systems and the other is resulted from user’s preference mechanisms. Characteristics of the two noises are presented aiming at the application of interac- tive genetic algorithms in dealing with images. The evolutionary phases of interactive genetic algorithms are determined according to differences in the same individual’s fitness among different generations. Models for noises in different phases are established and the corresponding strategies for reducing noises are given. The algorithm proposed in this paper has been applied to fashion design, which is a typical example of image processing. The results show that the strategies can reduce noises in interactive genetic algorithms and improve the algorithm’s performance effectively. However, a further study is needed to solve the problem of determining the evolution phase by using suitable objective methods so as to find out an effective method to decrease noises.

Evaluation of sorafenib for hepatocellular carcinoma by contrast-enhanced ultrasonography:A pilot study

AIM:To determine the usefulness of arrival time parametric imaging(AtPI) using contrast-enhanced ultrasonography(CEUS) with Sonazoid in evaluating early response to sorafenib for hepatocellular carcinoma(HCC).METHODS:Fourteen advanced HCC patients who received sorafenib 400/800 mg/d for at least 4 wk and were followed up by CEUS were enrolled in this study.CEUS was performed before treatment and 2 and 4 wk after treatment,and images of the target lesion in the arterial phase were recorded for each patient.The images were analyzed by AtPI.Color mapping(CM) images obtained by AtPI were compared before and after the treatment.In these CM images,the mean arrival time of the contrast agent in the region of interest from the starting point [mean time(MT)] was calculated.In each patient,differences between MT before and MT 2 and 4 wk after the treatment were compared with responses evaluated 4-8 wk after the treatment by dynamic computed tomography(CT),and statistical analysis was performed.Modified response evaluation criteria in solid tumors was used for the response evaluation.RESULTS:In CM images both 2 and 4 wk after the treatment,delays in the arrival time of the contrast agent were noted in 8 of the 14 patients.In the other 6 patients,no color changes were observed in the tumor,or red and/or yellow increase,suggesting a decrease in blood flow velocity between images 2 and 4 wk after the treatment and those before the treatment.Dynamic CT could be performed 4-8 wk after the treatment in 13 of the 14 patients.Median differences in the MT were 1.13 s and 1.015 s,2 and 4 wk after the treatment,respectively,in the 8 patients who showed stable disease(SD)/partial response(PR) on dynamic CT.Median differences in the MT were-0.39 s and-0.95 s,2 and 4 wk after the treatment,respectively,in the 5 patients who showed progressive disease(PD).Differences in the median MT between SD/PR and PD groups were significant 2 and 4 wk after the treatment with P = 0.019 and P = 0.028,respectively.CONCLUSION:AtPI by CEUS using Sonazoid is suggested to be useful for evaluating early responses to sorafenib.

320×240 Pixels CMOS Digital Image Sensor with Wide Dynamic Range

A 320×240 CMOS image sensor is demonstrated,which is implemented by a standard 0.6 μm 2P2M CMOS process.For reducing the chip area,each 2×2-pixel block shares a sample/hold circuit,analog-to-digital converter and 1-b memory.The 2×2 pixel pitch has an area of 40 μm×40 μm and the fill factor is about 16%.While operating at a low frame rate,the sensor dissipates a very low power by power-management circuit making pixel-level comparators in an idle state.A digital correlated double sampling,which eliminates fixed pattern noise,improves SNR of the sensor, and multiple sampling operations make the sensor have a wide dynamic range.

Time exposure acoustics in seismic exploration

An analysis of a passive seismic method for subsurface imaging is presented in which ambient seismic noise is employed as the source of illumination of subsurface scatterers. The imaging algorithm can incorporate new data into the image in a recursive fashion which causes image background noise to diminish over time. Under the assumption of spatially-incoherent ambient noise, an analytical expression for the point-spread function of the imaging algorithm is derived. The point-spread function （PSF） characterizes the resolution of the image, which is a function of the receiving array length and the ambient bandwidth.

Development of Automatic Extraction Weld for Industrial Radiographic Negative Inspection

In industrial X-ray inspection, in order to identify weld defects automatically, raise the identification ratio, and avoid processing of complex background, it is an important step for sequent processing to extract weld from the image. According to the characteristics of weld radiograph image, median filter is adopted to reduce the noise with high frequency, then relative gray-scale of image is chosen as fuzzy characteristic, and image gray-scale fuzzy matrix is constructed and suitable membership function is selected to describe edge characteristic. A fuzzy algorithm is adopted for enhancing radiograph image processing. Based on the intensity distribution characteristic in weld, methodology of weld extraction is then designed. This paper describes the methodology of all the weld extraction, including reducing noise, fuzzy enhancement and weld extraction process. To prove its effectiveness, this methodology was tested with 64 weld negative images available for this study. The experimental results show that this methodology is very effective for extracting linear weld.

Study of Image Denoising in Robot Visual Navigation System

In the technique of robot-assisted invasive surgery, high quality image is a key factor of the visual navigation system. In this paper, the authors have made a study of the image processing in visual system. Based on the analysis of plentiful demising methods, they proposed a new method （S-AM-W） which oxnbines Adaptive Median filter and Wioaer filter to renmve the main noises （Salt ＆ Pepper noise and Gattssian noise）. The sinlflation results show that it is simple, well real time, and has high Peak Signal-to-Noise Ratio （PSNR）. It was found that the new method is effective and efficient in dealing with medical image of background noise.

STATISTICAL PROBABILITY BASED ALGORITHM FOR EXTRACTING FEATURE POINTS IN 2-DIMENSIONAL IMAGE

An algorithm for automatically extracting feature points is developed after the area of feature points in 2-dimensional (2D) imagebeing located by probability theory, correlated methods and criterion for abnormity. Feature points in 2D image can be extracted only by calculating standard deviation of gray within sampled pixels area in our approach statically. While extracting feature points, the limitation to confirm threshold by tentative method according to some a priori information on processing image can be avoided. It is proved that the proposed algorithm is valid and reliable by extracting feature points on actual natural images with abundant and weak texture, including multi-object with complex background, respectively. It can meet the demand of extracting feature points of 2D image automatically in machine vision system.

Modified Laser Speckle Imaging with Adaptive Window

One of the advantages of laser speckle is detecting microvascular through image processing. This paper proposes a new image processing method for laser speckle, adaptive window method that adaptively processes laser speckle images in the space. Disadvantage of conventional fixed window method is that it uses the same window size regardless of target areas. Inherently laser speckle contains undesired noise. Thus a large window is helpful for removing the noise, but it results in low resolution of image. Otherwise a small window may detect micro vascular but it has limits in noise removal. To overcome this trade-off, the concept of adaptive window method is newly introduced to conventional laser speckle image analysis. In addition, the modified adaptive window method applied to other selection images. We have compared conventional Laser Speckle Contrast Analysis （LASCA） and its variants with the proposed method in terms of image quality and processing complexity, Moreover compared the result of the accompamed changing sdection images have also been compared.

Application of modified multiple subarrays detection method to multibeam bathymetry system

Either amplitude based methods or phase based methods are usually used in multibeam bathymetry system and chosen in practical measurement by ad hoc criteria. The errors of the detection are often caused by choosing wrong detection method. In this paper a modified multiple subarrays amplitude-phase united detection method is proposed , which uses both the amplitude and phase of echo from bottom.This new method not only realizes the super-wide swath coverage, but also improves the detection performance by using the phase differences among subarrays in place of phases of subarrays to estimate the phase slope image. Experimental results are also analyzed and discussed to demonstrate the effectivity of the proposed approach.