基于"WD倒谱"法分析人体脾组织的超声散射微结构特征

本文提出了一种对超声散射信号分析的新方法--“WD倒谱”法,并利用该方法对人体正常脾和脾增生组织的回波信号进行了分析,对软组织中散射子的平均间距进行了估计,结果表明：两种脾组织散射子的平均同距明显不同;“WD倒谱”能有效的反映软组织的微观结构特征,说明“WD倒谱”是软组织超声散射信号分析与软组织散射子平均间距定征的一种有效方法。     

中性粒细胞分布数据序列小波变换研究

目的　研究小波分析结合复倒谱处理血膜中中性粒细胞分布数据信号的新方法及临床意义。方法　利用“虚拟盒计数法”方法采集血膜中的细胞分布数据信号 ,然后进行小波变换结合复倒谱分析方法处理。结果　提出血膜中细胞分布状态的“密集子”新概念。计算出小波变换复倒谱主极大值 ,并以此作为不同情况下血膜中中性粒细胞分布“密集子”间距的准确参数。结论　方法简单 ,能较好的反映血膜中细胞分布状态的微观组织结构特征 ,是血膜中细胞“密集子”表达定征的一种有效方法     

Tracking voice change after thyroidectomy: application of spectral/cepstral analyses

This study evaluates the utility of perioperative spectral and cepstral acoustic analyses to monitor voice change after thyroidectomy. Perceptual and acoustic analyses were conducted on speech samples (sustained vowel /ɑ/ and CAPE-V sentences) provided by 70 participants (36 women and 34 men) at four study time points: prior to thyroid surgery and 2 weeks, 3 months and 6 months after thyroidectomy. Repeated measures analyses of variance focused on the relative amplitude of the dominant harmonic in the voice signal (cepstral peak prominence, CPP), the ratio of low-to-high spectral energy, and their respective standard deviations (SD). Data were also examined for relationships between acoustic measures and perceptual ratings of overall severity of voice quality. Results showed that perceived overall severity and the acoustic measures of the CPP and its SD (CPPsd) computed from sentence productions were significantly reduced at 2-week post-thyroidectomy for 20 patients (29% of the sample) who had self-reported post-operative voice change. For this same group of patients, the CPP and CPPsd computed from sentence productions improved significantly from 2-weeks post-thyroidectomy to 6-months post-surgery. CPP and CPPsd also correlated well with perceived overall severity (r = ?0.68 and ?0.79, respectively). Measures of CPP from sustained vowel productions were not as effective as those from sentence productions in reflecting voice deterioration in the post-thyroidectomy patients at the 2-week post-surgery time period, were weaker correlates with perceived overall severity, and were not as effective in discriminating negative voice outcome (NegVO) from normal voice outcome (NormVO) patients as compared to the results from the sentence-level stimuli. Results indicate that spectral/cepstral analysis methods can be used with continuous speech samples to provide important objective data to document the effects of dysphonia in a post-thyroidectomy patient sample. When used in conjunction with patient's self-report and other general measures of vocal dysfunction, the acoustic measures employed in this study contribute to a complete profile of the patient's vocal condition.     

基于反向滤波器的倒谱法估计平均骨小梁间距

目的 探讨用改进的倒谱方法估计平均骨小梁间距(mean trabecular bone spacing,MTBS)的可行性.方法 提出了一种基于反向滤波器的改进的倒谱分析方法用于估计MTBS,并将该方法应用于仿真及离体牛胫骨松质骨中的实验信号.结果 改进的倒谱方法能有效减少超声换能器脉冲响应和组织散射特性对倒谱的干扰,而且实现简单,计算量小.结论 相比于传统的倒谱方法,改进的倒谱方法在估计MTBS时, 对弥散散射和噪声有更强的鲁棒性,因此估计MTBS的精度更高.     

基于子波变换及其“WD倒谱”法的肾组织超声散射微结 …

本文提出了一种对超声散射信号分析的新方法－－“ＷＤ倒谱”法,并分别利用该方法和子波变换法对人体正常肾和肾肿瘤组织的超声回波信号进行了分析,对软组织中散射子的平均间距进行了估计,结果表明：两种肾组织散射子的平均间距明显不同;子波谱换及其“ＷＤ倒谱”能很即地反映软组织的微观结构特征,初步说明两种方法是软组织回波信号分析与软组织散射子平均间距定征的有效方法,但“ＷＤ倒谱”提高了子波变换对平均间距估计的分     

Parametric and non-parametric estimation of speech formants: application to infant cry

The present paper addresses the issue of correctly estimating the peaks in the speech envelope (formants) occurring in newborn infant cry. Clinical studies have shown that the analysis of such spectral characteristics is a helpful noninvasive diagnostic tool. In fact it can be applied to explore brain function at very early stages of child development, for a timely diagnosis of neonatal disease and malformation. The paper focuses on the performance comparison between some classical parametric and non-parametric estimation techniques particularly well suited for the present application, specifically the LP, ARX and cepstrum approaches. It is shown that, if the model order is correctly chosen, parametric methods are in general more reliable and robust against noise, but exhibit a less uniform behaviour than cepstrum. The methods are compared also in terms of tracking capability, since the signals under study are nonstationary. Both simulated and real signals are used in order to outline the relevant features of the proposed approaches.     

平脉与弦脉信号的声检测及两种谱研究

中医脉象的研究,首先要对正常人的脉象有所了解,然后才可能以常衡变,以变识病。本文采用一种高性能的声检测系统和频谱、倒谱分析技术,对94例健康人和32例高血压患者的脉象进行了检测和谱分析。结果表明:健康男性脉象频谱的第一主峰频率为1.213±0.166Hz,第二主峰频率为2.432±0.33Hz,第三主峰频率为3.640±0.483Hz,健康女性与之差异不大,但高血压弦脉之值明显比健康人的小。健康人5Hz以内的谱能量占总能量的90％左右,高血压仅占61％左右。而且发现,由倒谱可定量地反映出脉搏的强度大小并可准确地获得脉搏的周期值。     

Quantifying dysphonia severity using a spectral/cepstral-based acoustic index: Comparisons with auditory-perceptual judgements from the CAPE-V

This study investigated the relationship between acoustic spectral/cepstral measures and listener severity ratings in normal and disordered voice samples. CAPE-V sentence samples and the vowel /ɑ/were elicited from eight normal speakers and 24 patients with varying degrees of dysphonia severity. Samples were analysed for measures of the cepstral peak prominence (CPP), the ratio of low-to-high spectral energy, and their respective standard deviations. Perceptual ratings of overall severity were also obtained for all samples. Results showed that all acoustic variables combined in a four-factor model which correlated with perceived severity with R = 0.81 (R² = 0.65). For the vowel /ɑ/, a five-factor model incorporating all acoustic variables and gender correlated with perceived severity with R = 0.96 (R² = 0.91). Results indicate that a strong relationship between perceptual and acoustic estimates of dysphonia severity can be achieved in both continuous speech and vowel contexts using a model incorporating spectral/cepstral measures.     

梅尔频率倒谱系数在声带息肉手术前后嗓音分析中的价值研究

目的 本研究拟通过提取患者嗓音中的梅尔频率倒谱系数(MFCC)指标,探讨其在声带息肉手术前后嗓音分析中的临床价值。方法 回顾性分析于2018年1月—2019年8月行声带息肉手术且术前及术后1个月均行嗓音评估的患者41例,男31例,女10例;平均年龄(42.9±11.4)岁。另选取无声嘶且无声带病变的正常受试者21例作为基线对照。使用基于Python编程语言的librosa语音处理包进行MFCC特征提取,分别提取每位患者的MFCC均值,MFCC方差与MFCC标准差,使用配对样本t检验比较声带息肉手术前后上述各MFCC特征的差异。结果 声带息肉患者术后MFCC均值1.25±1.01、MFCC方差561.34±154.98及MFCC标准差21.74±4.03比术前MFCC均值6.81±2.05、MFCC方差1 019.66±295.87及MFCC标准差34.37±6.63显著下降,差异具有统计学意义(t=18.596,P=0.000;t=10.338,P=0.000;t=11.852,P=0.000)。声带息肉组患者术后1个月其MFCC均值、MFCC方差及MFCC标准差与正常受试者相比差异均无统计学意义,表明绝大部分声带息肉患者术后嗓音得到良好的恢复。结论 本研究首次探索了MFCC在声带息肉手术前后嗓音分析中的价值, MFCC各特征可作为评估声带息肉术后嗓音恢复的指标。     

连体乳腺正常与病变组织微观结构变化的AR倒谱分析

乳腺组织微观结构的准周期性可以利用散射体平均间距来描述,本文利用ＡＲ倒谱方法对连体正常与病变乳腺组织的散射体平均间距进行了估计,得到了正常乳腺组织的散射体平均间距约为１２５±０２１ｍｍ,各类病变组织的平均间距较正常组织有明显的特异性,所得结果与乳腺组织的微观结构特征相符