Evaluating Localization Accuracy of Automated Driving Systems

Automated driving systems are in need of accurate localization, i.e., achieving accuracies below 0.1 m at confidence levels above 95%. Although during the last decade numerous localization techniques have been proposed, a common methodology to validate their accuracies in relation to a ground-truth dataset is missing so far. This work aims at closing this gap by evaluating four different methods for validating localization accuracies of a vehicle’s position trajectory to different ground truths: (1) a static driving-path, (2) the lane-centerline of a high-definition (HD) map with validated accuracy, (3) localized vehicle body overlaps of the lane-boundaries of a HD map, and (4) longitudinal accuracy at stop points. The methods are evaluated using two localization test datasets, one acquired by an automated vehicle following a static driving path, being additionally equipped with roof-mounted localization systems, and a second dataset acquired from manually-driven connected vehicles. Results show the broad applicability of the approach for evaluating localization accuracy and reveal the pros and cons of the different methods and ground truths. Results also show the feasibility of achieving localization accuracies below 0.1 m at confidence levels up to 99.9% for high-quality localization systems, while at the same time demonstrate that such accuracies are still challenging to achieve.

HearMeVirtual Reality: Using Virtual Reality to Facilitate Empathy Between Hearing Impaired Children and Their Parents

Cochlear implants (CI) enable hearing in individuals with sensorineural hearing loss, albeit with difficulties in speech perception and sound localization. In noisy environments, these difficulties are disproportionately greater for CI users than for children with no reported hearing loss. Parents of children with CIs are motivated to experience what CIs sound like, but options to do so are limited. This study proposes using virtual reality to simulate having CIs in a school setting with two contrasting settings: a noisy playground and a quiet classroom. To investigate differences between hearing conditions, an evaluation utilized a between-subjects design with 15 parents (10 female, 5 male; age M = 38.5, SD = 6.6) of children with CIs with no reported hearing loss. In the virtual environment, a word recognition and sound localization test using an open-set speech corpus compared differences between simulated unilateral CI, simulated bilateral CI, and normal hearing conditions in both settings. Results of both tests indicate that noise influences word recognition more than it influences sound localization, but ultimately affects both. Furthermore, bilateral CIs are equally to or significantly beneficial over having a simulated unilateral CI in both tests. A follow-up qualitative evaluation showed that the simulation enabled users to achieve a better understanding of what it means to be an hearing impaired child.

Simplified assessment of central auditory processing in individuals presented with trisomy 21

ABSTRACT Purpose: to analyze the performance of individuals with trisomy 21 (T21) in the simplified assessment of central auditory processing, identify the impaired skills, and compare it with the results of the hearing self-perception questionnaire administered to the parents. Methods: a descriptive, observational, quantitative study conducted at the Speech-Language-Hearing Teaching Clinic of a public university. The sample comprised 16 individuals with T21, aged 8 to 33 years. Simplified assessment tests of central auditory processing were conducted, namely, sounds localization and sequential memory for verbal and nonverbal sounds, diotically. Then, the Scale of Auditory Behaviors (SAB) was administered to the subjects’ parents/guardians. The descriptive statistical analysis with the chi-square test considered p<0.05. Results: in the simplified assessment, 81.3% had abnormal results in the memory tests for verbal sounds; 75%, in the memory tests for nonverbal sounds; and 37.5%, in the sound localization test. In the Scale of Auditory Behaviors, 62.5% of the answers indicated changes in the central auditory processing, demonstrating that the scale can be useful to identify such changes. However, there was no significant association between the questionnaire and the behavioral test results. Conclusion: the results point to impaired sequential memory skills for verbal and nonverbal sounds in most individuals assessed. The simplified assessment results indicate the need for assessments of central auditory processing. Hence, the simplified assessment is highly important to detect possible changes in the central auditory processing that might interfere with the communication and overall learning of individuals presented with trisomy 21.

Music Playing and Interhemispheric Communication: Older Professional Musicians Outperform Age-Matched Non-Musicians in Fingertip Cross-Localization Test

Objective: Numerous investigations have documented that age-related changes in the integrity of the corpus callosum are associated with age-related decline in the interhemispheric transfer of information. Conversely, there is accumulating evidence for more efficient white matter organization of the corpus callosum in individuals with extensive musical training. However, the relationship between making music and accuracy in interhemispheric transfer remains poorly explored. Methods: To test the hypothesis that musicians show enhanced functional connectivity between the two hemispheres, 65 professional musicians (aged 56–90 years) and 65 age- and sex-matched non-musicians performed the fingertip cross-localization test. In this task, subjects must respond to a tactile stimulus presented to one hand using the ipsilateral (intra-hemispheric test) or contralateral (inter-hemispheric test) hand. Because the transfer of information from one hemisphere to another may imply a loss of accuracy, the value of the difference between the intrahemispheric and interhemispheric tests can be utilized as a reliable measure of the effectiveness of hemispheric interactions. Results: Older professional musicians show significantly greater accuracy in tactile interhemispheric transfer than non-musicians who suffer from age-related decline. Conclusions: Musicians have more efficient interhemispheric communication than age-matched non-musicians. This finding is in keeping with studies showing that individuals with extensive musical training have a larger corpus callosum. The results are discussed in relation to relevant data suggesting that music positively influences aging brain plasticity.

Quantitative evaluation of position sense in patients with parietal lesion

A position reproduction task was performed, in a controlled experimental environment, by seven patients with a parietal lobe lesion. We obtained mainly three findings: (a) even for patients who failed a thumb localization test, the accuracy of position reproduction was adequate and did not deviate from the range of error observed in healthy young participants, (b) the patients showed a centralizing tendency in localization, and (c) they initially moved in the wrong direction when reproducing the remembered positions. The study also indicated that patients whose lesion sites included the postcentral gyrus exhibited stronger exploratory movements than those who had no such lesions and lacked smoothness of movement. In patients without the lesion of the postcentral gyrus, a higher-order dysfunction, rather than the pure position sense problem, was suggested to contributed to their task performance. The present study provided fundamental data for sensorimotor skills of patients with parietal lesion, and these quantitative findings would also contribute to reconsideration of current assessments and rehabilitations for sensory deficits.

Comparing the Effect of Different Hearing Aid Fitting Methods in Bimodal Cochlear Implant Users

PurposeThe aim of the study was to investigate the effect of 3 hearing aid fitting procedures on provided gain of the hearing aid in bimodal cochlear implant users and their effect on bimodal benefit.MethodThis prospective study measured hearing aid gain and auditory performance in a cross-over design in which 3 hearing aid fitting methods were compared. Hearing aid fitting methods differed in initial gain prescription rule (NAL-NL2 and Audiogram+) and loudness balancing method (broadband vs. narrowband loudness balancing). Auditory functioning was evaluated by a speech-in-quiet test, a speech-in-noise test, and a sound localization test. Fourteen postlingually deafened adult bimodal cochlear implant users participated in the study.ResultsNo differences in provided gain and in bimodal performance were found for the different hearing aid fittings. For all hearing aid fittings, a bimodal benefit was found for speech in noise and sound localization.ConclusionOur results confirm that cochlear implant users with residual hearing in the contralateral ear substantially benefit from bimodal stimulation. However, on average, no differences were found between different types of fitting methods, varying in prescription rule and loudness balancing method.

Sound Localization Test in Presence of Noise (Sound Localization Test) in Adults without Hearing Alteration

Introduction Even people with normal hearing may have difficulties locating a sound source in unfavorable sound environments where competitive noise is intense. Objective To develop, describe, validate and establish the normality curve of the sound localization test. Method The sample consisted of 100 healthy subjects with normal hearing, > 18 years old, who agreed to participate in the study. The sound localization test was applied after the subjects underwent a tonal audiometry exam. For this purpose, a calibrated free field test environment was set up. Then, 30 random pure tones were presented in 2 speakers placed at 45° (on the right and on the left sides of the subject), and the noise was presented from a 3rd speaker, placed at 180°. The noise was presented in 3 hearing situations: optimal listening condition (no noise), noise in relation to 0 dB, and noise in relation to - 10 dB. The subject was asked to point out the side where the pure tone was being perceived, even in the presence of noise. Results All of the 100 participants performed the test in an average time of 99 seconds. The average score was 21, the medium score was 23, and the standard deviation was 3.05. Conclusion The sound localization test proved to be easy to set-up and to apply. The results obtained in the validation of the test suggest that individuals with normal hearing should locate 70% of the presented stimuli. The test can constitute an important instrument in the measurement of noise interference in the ability to locate the sound.

Personalized HRTF Modeling Based on Deep Neural Network Using Anthropometric Measurements and Images of the Ear

This paper proposes a personalized head-related transfer function (HRTF) estimation method based on deep neural networks by using anthropometric measurements and ear images. The proposed method consists of three sub-networks for representing personalized features and estimating the HRTF. As input features for neural networks, the anthropometric measurements regarding the head and torso are used for a feedforward deep neural network (DNN), and the ear images are used for a convolutional neural network (CNN). After that, the outputs of these two sub-networks are merged into another DNN for estimation of the personalized HRTF. To evaluate the performance of the proposed method, objective and subjective evaluations are conducted. For the objective evaluation, the root mean square error (RMSE) and the log spectral distance (LSD) between the reference HRTF and the estimated one are measured. Consequently, the proposed method provides the RMSE of −18.40 dB and LSD of 4.47 dB, which are lower by 0.02 dB and higher by 0.85 dB than the DNN-based method using anthropometric data without pinna measurements, respectively. Next, a sound localization test is performed for the subjective evaluation. As a result, it is shown that the proposed method can localize sound sources with higher accuracy of around 11% and 6% than the average HRTF method and DNN-based method, respectively. In addition, the reductions of the front/back confusion rate by 12.5% and 2.5% are achieved by the proposed method, compared to the average HRTF method and DNN-based method, respectively.

Combined Effects of Noise and Reverberation on Sound Localization for Listeners With Normal Hearing and Bilateral Cochlear Implants

Purpose This study examined the individual and combined effects of noise and reverberation on the ability of listeners with normal hearing (NH) and with bilateral cochlear implants (BCIs) to localize speech. Method Six adults with BCIs and 10 with NH participated. All subjects completed a virtual localization test in quiet and at 0-, −4-, and −8-dB signal-to-noise ratios (SNRs) in simulated anechoic and reverberant (0.2-, 0.6-, and 0.9-s RT 60 ) environments. BCI users were also tested at +8- and +4-dB SNR. A 3-word phrase was presented at 70 dB SPL from 9 simulated locations in the frontal horizontal plane (±90°), with the noise source at 0°. Results BCIs users had significantly poorer localization than listeners with NH in all conditions. BCI users' performance started to decrease at a higher SNR (+4 dB) and shorter RT 60 (0.2 s) than listeners with NH (−4 dB and 0.6 s). The combination of noise and reverberation began to degrade localization of BCI users at a higher SNR and a shorter RT 60 than listeners with NH. Conclusion The clear effect of noise and reverberation on the performance of BCI users provides information that should be useful for refining cochlear implant processing strategies and developing cochlear implant rehabilitation plans to optimize binaural benefit for BCI users in everyday listening situations.