A lightwave 3d plug-in for modelling long hair on virtual humans

Multimedia applications today make use of virtual humans. Generating realistic virtual humans is a challenging problem owing to a number of factors, one being the simulation of realistic hair. The difficulty in simulating hair is due to the physical properties of hair. The average human head holds thousands of hairs, with the width of each hair often smaller than the size of a pixel. There are also complex lighting effects that occur within hair. This paper presents a LightWave 3D plug-in for modeling thousands of individual hairs on virtual humans. The plug-in allows the user to specify the length, thickness and distribution of the hair, as well as the number of segments a hair is made up of. The plug-in is able to add hairs to a head model, which the user then modifies to define a hairstyle. The hairs are then multiplied by the plug-in to produce many hairs. By providing a plug-in that does most of the work and produces realistic results, the user is able to produce a hairstyle without modeling each individual strand of hair. This greatly reduces the time spent on hair modeling, and makes the possibility of adding realistic long hair to virtual humans reasonable.

The identification of mammalian species through the classification of hair patterns using image pattern recognition

The identification of mammals through the use of their hair is important in the fields of forensics and ecology. The application of computer pattern recognition techniques to this process provides a means of reducing the subjectivity found in the process, as manual techniques rely on the interpretation of a human expert rather than quantitative measures. The first application of image pattern recognition techniques to the classification of African mammalian species using hair patterns is presented. This application uses a 2D Gabor filter-bank and motivates the use of moments to classify hair scale patterns. Application of a 2D Gabor filter-bank to hair scale processing provides results of 52% accuracy when using a filter bank of size four and 72% accuracy when using a filter-bank of size eight. These initial results indicate that 2D Gabor filters produce information that may be successfully

Blood mineral, trace-element and vitamin concentrations in Huacaya alpacas and Merino sheep grazing the same pasture

We aimed to determine whether the concentration of minerals and trace constituents in blood of Merino sheep and Huacaya alpacas grazing the same pasture differed with species and time of sampling. Blood samples and pasture samples were collected at frequent intervals over a period of 2 years for mineral and trace-nutrient assay. The concentration of the minerals and trace nutrients in the grazed pasture usually met the dietary needs of sheep at maintenance, apart from potassium, sulfur, cobalt and Vitamin E in occasional samples. Restricted maximum likelihood mixed model analysis indicated a significant (P < 0.001) species by month by year interaction for all blood constituents assayed, a significant (P < 0.05) species by coat shade interaction for plasma Vitamin D, E and B12 and a significant (P < 0.001) species by month by Vitamin D interaction for plasma phosphorus concentrations. In general, plasma calcium concentrations were greater in sheep than in alpacas but plasma magnesium concentrations were greater in alpacas than in sheep. There was no consistent difference between the two species in plasma phosphorus concentrations although low values were recorded in individual sheep and alpacas. Plasma Vitamin D concentrations were more responsive to increasing hours of sunlight in alpacas than they were in sheep. Sheep had consistently higher concentrations of plasma copper, zinc and Vitamin B12 and higher concentrations of blood selenium but lower concentrations of plasma selenium and Vitamin A, than did alpacas. No consistent difference was observed between the two species in plasma Vitamin E concentrations.

Relationships between skin follicle characteristics and fibre properties of Suri and Huacaya alpacas and Peppin Merino sheep

We aimed to quantify the number, type and arrangement of skin follicles in Huacaya and Suri alpaca skin and correlate their follicle characteristics with fibre traits of harvested fibre and compared these relationships with those of Merino sheep. Fibre and skin samples were collected from the mid-side of 12 Huacaya alpacas, 24 Suri alpacas and 10 Merino sheep. The mean fibre diameter (MFD ± s.e.) of the Huacaya and Suri were: 35.5 ± 0.9 and 28.3 ± 1.0 μm, respectively. The follicle groups found for alpacas were very different from the normal trio of primary follicles found in sheep and goats. The follicle group of the alpacas consisted of a single primary follicle surrounded by a variable number of secondary follicles. The mean ± s.e. primary follicle density was 3.1 ± 0.3 and 2.7 ± 0.1 follicles/mm² for Huacaya and Suri, respectively. The mean ± s.e. secondary follicle density (SFD) was 13.7 ± 1.2 and 17.5 ± 0.6 follicles/mm² for Huacaya and Suri, respectively. The mean ± s.e. ratio of secondary to primary follicles (S/P ratio) was 5.1 ± 0.5 for the Huacaya and 7.3 ± 0.2 for the Suri alpacas. The sheep had higher S/P ratios and SFD, lower MFD and produced significantly heavier fleeces. The key correlations found between traits in alpacas include a negative correlation between SFD and MFD (r = –0.71, P = 0.001) and a negative correlation between S/P ratio and MFD (r = –0.44, P = 0.003) and a positive correlation between S/P ratio and total follicle density (r = 0.38, P = 0.010). The study revealed that important relationships exist between alpaca skin follicle characteristics and fibre characteristics. It was the number of secondary follicles in a group that imparts density and a corresponding reduced MFD.