ABSTRACT
BACKGROUND/OBJECTIVE: Artificial bone models (ABMs) are used in orthopaedics for research of biomechanics, development of implants and educational purposes. Most of the commercially available ABMs approximate the morphology of Europeans, but they may not depict the Asian anatomy. Therefore, our aim was to develop the first Asian ABM of the pelvis and compare it with the existing pelvic ABM (Synbone®; Caucasian male). METHODS: One hundred clinical computed tomography (CTs) of adult pelvises (male n â= â50, female n â= â50) of Malay, Chinese and Indian descent were acquired. CTs were segmented and defined landmarks were placed. Three 3D statistical pelvic model and mean models (overall, male, female) were generated. Anatomical variations were analysed using principal component analysis. To measure gender-related differences and differences to the existing ABM, distances between the anterior superior iliac spines (ASIS), the anterior inferior iliac spines (AIIS), the promontory and the symphysis (conjugate vera, CV) as well as the ischial spines (diameter transversa, DT) were quantified. RESULTS: Principal component analysis displayed large variability regarding the pelvic shape and size. Female and male statistical models were similar in ASIS (225 â± â20; 227 â± â13 âmm; P â= â0.4153) and AIIS (185 â± â11; 187 â± â10 âmm; P â= â0.3982) and differed in CV (116 â± â10; 105 â± â10 âmm; P â< â0.0001) and DT (105 â± â7; 88 â± â8 âmm; P â< â0.0001). Comparing the unisex mean model with the pre-existing ABM, the ASIS (226; 275 âmm; P â< â0.0001), the AIIS (186; 209 âmm; P â< â0.0001) and the CV (111; 105 âmm; P â< â0.0001) differed significantly. Both models were similar regarding DT (97; 95 âmm; P â= â0.6927). The analysis revealed notable gender- and size-dependent anatomical variations within the Asian population. Chinese, Malay and Indian descents did not differ notably. The overall Asian model was smaller than the existing ABM. THE TRANSLATION POTENTIAL OF THIS ARTICLE: Owing to the large differences between the Asian ABM and the pre-existing ABM, as well as differences between genders, the use of an Asian- and gender-specific ABM is important to consider in research, biomechanics and implant development for this population.
ABSTRACT
Human visual system makes an extensive use of visual attention in order to select the most relevant information and speed-up the vision process. Inspired by visual attention, several computer models have been developed and many computer vision applications rely today on such models. However, the actual algorithms are not suitable to omnidirectional images, which contain a significant amount of geometrical distortion. In this paper, we present a novel computational approach that performs in spherical geometry and thus is suitable for omnidirectional images. Following one of the actual models of visual attention, the spherical saliency map is obtained by fusing together intensity, chromatic, and orientation spherical cue conspicuity maps that are themselves obtained through multiscale analysis on the sphere. Finally, the consecutive maxima in the spherical saliency map represent the spots of attention on the sphere. In the experimental part, the proposed method is then compared to the standard one using a synthetic image. Also, we provide examples of spots detection in real omnidirectional scenes which show its advantages. Finally, an experiment illustrates the homogeneity of the detected visual attention in omnidirectional images.
Subject(s)
Algorithms , Biomimetics/methods , Fixation, Ocular/physiology , Image Interpretation, Computer-Assisted/methods , Models, Neurological , Pattern Recognition, Automated/methods , Visual Perception/physiology , Computer Simulation , HumansABSTRACT
The aim of this study was to investigate how oculomotor behaviour depends on the availability of colour information in pictorial stimuli. Forty study participants viewed complex images in colour or grey-scale, while their eye movements were recorded. We found two major effects of colour. First, although colour increases the complexity of an image, fixations on colour images were shorter than on their grey-scale versions. This suggests that colour enhances discriminability and thus affects low-level perceptual processing. Second, colour decreases the similarity of spatial fixation patterns between participants. The role of colour on visual attention seems to be more important than previously assumed, in theoretical as well as methodological terms.
