Speech cues interrupted by fewer of these conditions will be more available to the listener, and will thus have a higher sii value. Animals studies that induce chronic conductive pathologies can result in significant changes in central auditory pathways. High correlations with the intelligibility of vocoded speech were also obtained in our previous study. Speech intelligibility analyser users guide warning systems dsp2 dedicated speech intelligibility meter measures sound pressure level and speech intelligibility index in cis or sti formats using the option sticistm software. One type of quantitative test used to measure speech intelligibility is called speech transmission index public. Most of the objective measures proposed after sii share the assumption that the intelligibility of a speech signal is given by the sum of the contributions to intelligibility within individual frequency bands french and steinberg. While both metrics were reduced by glimpsing and lowpass. Extended speech intelligibility index for the prediction of the speech.
The collection of papers is the main part of the thesis. Objective measures for predicting speech intelligibility. Based on this, a gain function is defined to filter the noisy speech 10. A common representation of speech used for instrumental intelligibility measures, including this work, is the subband temporal envelope.
Finally, the difference between speech intelligibility and speech quality is considered, and methods for evaluation of speech intelligibility are discussed. The level of speech privacy and speech distraction are indicated by the privacy distance rp and distraction distance r d. The technique utilizes the coherence between the target and noise signals as a criterion for noise reduction and can be generally applied to arrays with closely spaced microphones, where noise captured by the sensors is. Currently, there are three different programs available for calculating the speech intelligibility index sii. Defines a method for computing a physical measure that is highly correlated with the intelligibility of speech as evaluated by speech perception tests given a group of talkers and listeners. An intelligibility metric based on a simple model of speech communication steven van kuyk1, w. Measurement of speechintelligibility stipa according to. Yantek national institute for occupational safety and health pittsburgh, pennsylvania, usa. Citeseerx document details isaac councill, lee giles, pradeep teregowda. A method to estimate speech intelligibility has been developed that mimics the multiresolution nature of human hearing and can be used with. Speech intelligibility testing is a method used to determine if an emergency communication system ecs also called mass notification system, mns is clear, precise, and audible or intelligible. Speech intelligibility index, the model is applied to predict the speech intelligibility data measured by. Distortions in the system under test may affect the mtf hence the measured speech intelligibility differently from the real speech intelligibility.
A key aspect to a childs development of speech and language mentor. In most cases this must be performed according to iec 60849 or iso. A band importance function, which describes the relative importance of the diff erent frequency bands for speech may be seen in figure 1. How to calculate speech intelligibility these instructions will guide you through a speech intelligibility assessment. Find, read and cite all the research you need on researchgate. If a naiveimpartial listener is not available, it is helpful to present the word list on index cards one word per card so that the order of presentation can be randomized. Children need greater audibility to achieve the same intelligibility. The articulation index ai, speech transmission index sti, and coherence based intelligibility metrics have been evaluated primarily in steadystate noisy conditions and have not been tested extensively in. Intelligibility in context scale is licensed under a creative commons attribution.
An evaluation of intrusive instrumental intelligibility metrics arxiv. The csii is a spectralbased speech intelligibility measure which takes into account the coherence e. Home acm journals ieeeacm transactions on audio, speech and language processing vol. Classical speech intelligibility models, such as the speech transmission index sti and the speech intelligibility index sii are based on calculations on the physical acoustic signals. The sti measures some physical characteristics of a transmission channel a room, electroacoustic equipment, telephone line, etc. This assessment is typically used by a speech pathologist in the early stages of determining whether or not a childs language is developmentally appropriate for their age. Citeseerx a dualmicrophone speech enhancement algorithm. Ai evolved to the speech intelligibility index sii, and has been standardized in 1997 under ansi 3. The first program, which can be run in any microsoft windows environment, provides a versatile graphical user interface.
Coherence and the speech intelligibility index james m. Speech privacy and intelligibility in openplan offices as. Factors governing the intelligibility of speech sounds. Intelligibility is affected by the level loud but not too loud and quality of the speech signal, the type and level of background noise, reverberation some reflections but not too many, and, for speech over communication devices, the properties of the communication system. Pdf coherence and the speech intelligibility index researchgate. Speech transmission index sti is a measure of speech transmission quality. Speech intelligibility index sii is a measure, between 0 and 1, that represents the intelligibility of speech under a variety of adverse listening conditions, such as noise masking, filtering, and reverberation. An improved speech processing strategy for cochlear. Generally, there is a monotonic relationship between the sii and speech understanding.
For new public buildings a certification measurement is required and the speech intelligibility results must be documented. A binaural grouping model for predicting speech intelligibility in. Relationships between the modified rhyme test mrt and the speech transmission index sti, and mrt and the speech intelligibility index sii, have been obtained for additive stationary noise. Intelligibility is an overall measure of the understandability of speech and often used clinically as an index of the activity limitation of a speaker or the overall severity of a communication. In many countries there exist limits for the speech intelligibility.
Abstracta novel dualmicrophone speech enhancement technique is proposed in the present paper. The coherence speech intelligibility index csii 15 is based on the sii, but replaces the snr of each frequency band with a signaltodistortion ratio sdr. For instance, a recorded voice that is played back at a slightly higher speed is still very intelligible, but the. The most effective procedure divides the speech signal into low, mid, and highlevel regions, computes the coherence sii separately for the signal segments in each region, and then estimates intelligibility from a weighted combination of the three coherence sii values. Retained target energy ratio of the rms levels of the glimpsedfiltered stimulus and the intactunfiltered stimulus. The sii the speech intelligibility index sii is a measure of the total speech information available to a listeners ear for. Kates and arehart 3 proposed a hearingaid speech perception index haspi for hearing impaired hi and normal hearing nh listeners that was an extension of the threelevel coherence speech intelligibility index. Katesa gn resound and university of colorado, department of speech language and hearing sciences. Objective speech intelligibility measurement for cochlear.
Virginia best, elin roverud, lucas baltzell, jan rennies. In speech communication, intelligibility is a measure of how comprehensible speech is in given conditions. Perceptual coherence in listeners having longstanding. All three calculate the sii in accordance with the ansi s3. Chronic otitis media early in childhood is often voiced as a concern for speech language delay, though the research is inconclusive. Conductive hearing loss and speech intelligibility.
This version of the intelligibility in context scale can be copied. Predicting speech intelligibility using a gammachirp. The new metric is called speech coherence index sci, and is compared to sti under simulated conditions with uncorrelated noise. Introduction o ne of the most common complaints made by hearing impaired listeners is reduced speech intelligibility in noisy environments. That is, as the sii increases, speech understanding generally increases. In order to compute csii values, a shorttime fourier transform is first performed such that each time. Speech transmission index the speech transmission index sti is an objective method. The speech intelligibility index, or sii, is a measure, ranging between 0. Jacob oleson colorado college north central college. Iec standard 6026816 objective rating of speech intelligibility by speech transmission index. Index terms coherence function, coherent noise, microphone array, noise reduction. The sii concept for estimating intelligibility is extended in this paper to include broadband peakclipping. The level of speech intelligibility is indicated by reverberation time t 30, clarity index for speech c 50, and rasti. Using the coherence based function, noise is suppressed along with distortion in speech 3.
Perceptual coherence, the process by which the individual elements of complex sounds are bound together, was examined in adult listeners with longstanding childhood hearing losses, listeners with adultonset hearing losses, and listeners with normal hearing. Estimating the performance of sound restoration hearing protectors by using the speech intelligibility index amanda s. Let xi be a realvalued random process that represents the samples of an acoustic speech signal where iis the sample index. Assessing speech intelligibility in children with hearing. Pdf relationships between the modified rhyme test and. Objective measures for predicting speech intelligibility in noisy. Katesa gn resound and university of colorado, department of speech language and hearing sciences, 409 ucb, boulder, colorado 80309. Hendriks2 1victoria university of wellington, new zealand 2 delft university of technology, the netherlands abstract instrumental measures of speech intelligibility typically produce an. The absolute measurement of speech intelligibility is a complex science. The mtf as a basis for the speech intelligibility also has its limitations.
A testing system for speech intelligibility in a noisy environment was developed and as a first. Existing intelligibility prediction methods may be divided into two classes. The articulation index ai, speech transmission index sti, and coherence based intelligibility metrics have been evaluated primarily in steadystate noisy conditions and have not been tested extensively in fluctuating noise conditions. This article is available as html full text and pdf. Noise dependent super gaussiancoherence based dual. Several speech transmission index sti and coherence based intelligibility measures have based used extensively for predicting the intelligibility of wideband speech, but have not been examined with vocoded speech. Objective intelligibility measures based on mutual.
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