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Mingxi Wan

Publications and source records attributed to Mingxi Wan.

24 records · Page 2Linked to original sources
PubMed2004

A tunable incremental factor augmented inverse image alignment method in fundus angiogram registration and mosaicing.

A tunable incremental factor is introduced into the inverse compositional image alignment method in registration of fundus blood vessel angiograms under confocal scanning laser ophthalmoscope. The augmented version need less iteration to converge and hardly causes degradation to the registration precision, mainly due to the favorable convexity of the sum of squared differences (SSD) function between the angiograms around the correct registration. And as a compromise between the fidelity of diagnostic information and visual purpose, an adaptive blending strategy based on undecimated discrete sequence wavelet transform is presented in this paper to mosaic fundus angiograms. The effectiveness and efficiency of the tunable incremental factor algorithm is exemplified in the experimental results on clinical indocyanine green angiograms, and the convexity of the SSD function under ideal imaging condition is also illustrated in the paper.

Algorithms↗
PubMed2004

Aerodynamic characteristics of laryngectomees breathing quietly and speaking with the electrolarynx.

The primary purpose of this study was to investigate the aerodynamic characteristics of laryngectomees under two conditions: breathing quietly and speaking with electrolarynx. Twenty male adult subjects, 8 normal speakers, and 12 laryngectomees participated the experiment. Airflow, pressure, and speech data were obtained simultaneously. The acceptability of electrolarynx speech under different conditions was also evaluated by 20 listeners (14 men, 6 women). Results indicated a higher peak expiration airflow and pressure among the laryngectomees as compared with the normal during breathing. Three different breathing patterns appeared among the laryngectomees when speaking with the electrolarynx: holding breath, exhaling, and breathing. Four long-time electrolarynx users held breath during speaking. Seven of 12 laryngectomees kept exhaling, whereas only 1 could breathe during speech production. In addition, (1) the acceptability of electrolarynx speech was the highest when speaking breathlessly; (2) no significant difference was found in the acceptability between the patterns of exhaling and breathing smoothly; and (3) the acceptability decreased if breathing quickly during phonation with the electrolarynx. It also suggests that the laryngectomees who can breathe during speaking may be more appropriate to use the new electrolarynx controlling the pitch by expiration pressure.

Adult↗
PubMed2004

Effects of fascia lata on HIFU lesioning in vitro.

The effects of fascia lata on high intensity focused ultrasound (US), or HIFU,-induced lesions were demonstrated through comparison with and without fascia lata in bovine thigh muscle tissue. Experiments were conducted in an arrangement with a three-way multiscan ultrasonic inspection system and imaging done by B-mode US. Bovine thigh muscle (8-cm thick) was treated with 1.5 MHz for 8 s. Spatial peak intensity (ISP) was 3000 W/cm2. B-mode US imaging detected appearance at the HIFU treatment site. At a free-field intensity of 4000 W/cm2, the observed lesion length (along the axis) with fascia lata was 12 +/- 1.82 mm, compared with 4 +/- 1.54 mm for samples without fascia lata. At 3000 W/cm2, the values for samples with fascia lata and samples without fascia lata, respectively, were 13 +/- 1.50 mm and 2 +/- 1.42 mm. During a 30-s exposure, at ISP of 2000 W/cm2, the peak temperature reached 41 degrees C in samples without fascia lata and 70 degrees C in samples with fascia lata. At ISP of 3000 and 4000 W/cm2, the peak temperature reached, respectively, 73 degrees C and 84 degrees C in samples without fascia lata, compared with 102 degrees C and 104 degrees C, respectively, for samples with fascia lata. The results confirm that fascia lata contributes to increasing tissue necrosis, temperature elevation and echogenicity in US images.

Animals↗
PubMedDate not supplied

Inverse image alignment method for image mosaicing and video stabilization in fundus indocyanine green angiography under confocal scanning laser ophthalmoscope.

An efficient image registration algorithm, the Inverse Compositional image alignment method based on minimization of Sum of Squared Differences of images, is applied in fundus blood vessel angiography under confocal scanning laser ophthalmoscope, to build image mosaics which have larger field of view without loss of resolution to assist diagnosis. Furthermore, based on similar technique, the angiography video stabilization algorithm is implemented for fundus documenting. The actual underlying models of motion between images and corresponding convergence criteria are also discussed. The experiment results in fundus images demonstrate the effectiveness of the registration scheme.

Algorithms↗
PubMedDate not supplied

Features of listeners affecting the perceptions of Mandarin electrolaryngeal speech.

The effect of age and gender of listeners on the perceptions of Mandarin electrolaryngeal speech was investigated. Sixty males and 40 females were categorized into five age groups (20-29, 30-39, 40-49, 50-59, and 60-70 years), who were regarded as naive listeners for having no experience with electrolaryngeal speech. They were instructed to score acceptability of a passage and intelligibility of isolated words and embedded words. The results revealed no gender effects but significant age effects on the perceptual evaluation. It was more difficult for the 50-59 and 60-70 groups to understand electrolaryngeal speech. The results were also analyzed for tonal and segmental errors, and errors of tone alone were found to occur more often than segmental errors. In addition, a preliminary study was presented for the perceptions of the four Mandarin tones. Higher percent correct identification was found for the high-level tone compared to the other three tones.

Adult↗