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Objectives The main objective of this retrospective study was to assess functional results in endoscopic Zenker's diverticulum surgery. The secondary objectives were to assess safety, identify recurrence risk factors, and determine optimal management of recurrence. Material and methods From 2000 to 2014, 50 patients underwent endoscopic surgery for marsupialization of Zenker's diverticulum. Regurgitation and dysphagia were assessed on the FOIS scale, pre- and post-operatively. Recurrences and complications rates were determined retrospectively at a minimum 18 months’ follow-up. Results Regurgitation and dysphagia improved in respectively 96% and 86% of patients. There was a 12% rate of complications, mostly minor. Mean hospital stay and time to return to oral feeding were 2.0 and 1.3 days respectively. Nine patients (18%) showed recurrence of symptoms, requiring revision surgery at a mean 2.7 years, performed endoscopically in the majority of cases. Only one recurrence risk factor was identified: small diverticulum size. Conclusion Endoscopic Zenker's diverticulum surgery provided functional improvement in most cases. Safe and effective, it is currently the treatment of choice for Zenker's diverticulum. [ABSTRACT FROM AUTHOR]

A stereo matching algorithm dedicated to complex urban scenes is described. It relies on successive complementary matching steps, based on dynamic programming. First, intensity edges of both images are matched, which produces piecewise continuous 3D chains. This provides a description of the scene structure containing the highest elevation ofmost height discontinuities. Then the interval pairs defined by the matched edges are matched in a hierarchical way, by a radio-metrically constrained process followed by a geometrically constrained one. The novelty of the approach lies in the use of several successive stepsappropriate to different kinds of pixels. It provides dense disparity maps with less noise, while preserving discontinuities, which are acharacteristic of urban digital elevation models. The method has proved reliable (producing few noisy and altimetrically accurate 3D data) and fast, and is robust to image variability. Perspectives within an industrial production context are discussed. [ABSTRACT FROM AUTHOR]

The two experiments described here use a formant-matching task to investigate what abstract representations of sound are available to listeners. The first experiment examines how veridically and reliably listeners can adjust the formant frequency of a single-formant sound to match the timbre of a target single-formant sound that has a different bandwidth and either the same or a different fundamental frequency (F0). Comparison with previous results [Dissard and Darwin, J. Acoust. Soc. Am. 106, 960-969 (2000)] shows that (i) for sounds on the same F0, introducing a difference in bandwidth increases the variability of matches regardless of whether the harmonics close to the formant are resolved or unresolved; (ii) for sounds on different F0's, introducing a difference in bandwidth only increases variability for sounds that have unresolved harmonics close to the formant. The second experiment shows that match variability for sounds differing in F0, but with the same bandwidth and with resolved harmonics near the formant peak, is not influenced by the harmonic spacing or by the alignment of harmonics with the formant peak. Overall, these results indicate that match variability increases when the match cannot be made on the basis of the excitation pattern, but match variability does not appear to depend on whether ideal matching performance requires simply interpolation of a spectral envelope or also the extraction of the envelope's peak frequency.

The four experiments reported here measure listeners' accuracy and consistency in adjusting a formant frequency of one- or two-formant complex sounds to match the timbre of a target sound. By presenting the target and the adjustable sound on different fundamental frequencies, listeners are prevented from performing the task by comparing the absolute or relative levels of resolved spectral components. Experiment 1 uses two-formant vowellike sounds. When the two sounds have the same F0, the variability of matches (within-subject standard deviation) for either the first or the second formant is around 1%-3%, which is comparable to existing data on formant frequency discrimination thresholds. With a difference in F0, variability increases to around 8% for first-formant matches, but to only about 4% for second-formant matches. Experiment 2 uses sounds with a single formant at 1100 or 1200 Hz with both sounds on either low or high fundamental frequencies. The increase in variability produced by a difference in F0 is greater for high F0's (where the harmonics close to the formant peak are resolved) than it is for low F0's (where they are unresolved). Listeners also showed systematic errors in their mean matches to sounds with different high F0's. The direction of the systematic errors was towards the most intense harmonic. Experiments 3 and 4 showed that introduction of a vibratolike frequency modulation (FM) on F0 reduces the variability of matches, but does not reduce the systematic error. The experiments demonstrate, for the specific frequencies and FM used, that there is a perceptual cost to interpolating a spectral envelope across resolved harmonics.