Interpolation of 3-D binary images based on morphological skeletonization.

In this paper, the morphological skeleton interpolation (MSI) algorithm is presented. It is an efficient, shape-based interpolation method used for interpolating slices in a three-dimensional (3-D) binary object. It is based on morphological skeletonization, which is used for two-dimensional (2-D) slice representation. The proposed morphological skeleton matching process provides translation, rotation, and scaling information at the same time. The interpolated slices preserve the shape of the original object slices, when the slices have similar shapes. It can also modify the shape of an object when the successive slices do not have similar shapes. Applications on artificial and real data are also presented.

A generalized fuzzy mathematical morphology and its application in robust 2-D and 3-D object representation.

In this paper, the generalized fuzzy mathematical morphology (GFMM) is proposed, based on a novel definition of the fuzzy inclusion indicator (FII). FII is a fuzzy set used as a measure of the inclusion of a fuzzy set into another, that is proposed to be a fuzzy set. It is proven that the FII obeys a set of axioms, which are proposed to be extensions of the known axioms that any inclusion indicator should obey, and which correspond to the desirable properties of any mathematical morphology operation. The GFMM provides a very powerful and flexible tool for morphological operations. The binary and grayscale mathematical morphologies can be considered as special cases of the proposed GFMM. An application for robust skeletonization and shape decomposition of two-dimensional (2-D) and three-dimensional (3-D) objects is presented. Simulation examples show that the object reconstruction from their skeletal subsets that can be achieved by using the GFMM is better than by using the binary mathematical morphology in most cases. Furthermore, the use of the GFMM for skeletonization and shape decomposition preserves the shape and the location of the skeletal subsets and spines.

Fuzzy scalar and vector median filters based on fuzzy distances.

In this paper, the fuzzy scalar median (FSM) is proposed, defined by using ordering of fuzzy numbers based on fuzzy minimum and maximum operations defined by using the extension principle. Alternatively, the FSM is defined from the minimization of a fuzzy distance measure, and the equivalence of the two definitions is proven. Then, the fuzzy vector median (FVM) is proposed as an extension of vector median, based on a novel distance definition of fuzzy vectors, which satisfy the property of angle decomposition. By defining properly the fuzziness of a value, the combination of the basic properties of the classical scalar and vector median (VM) filter with other desirable characteristics can be succeeded.

Intravitreal application of ganciclovir in rabbits: ERG and electron-microscopic findings.

The retinal toxic effect after intravitreal use of ganciclovir has been the subject of our experimental investigation on 20 New Zealand rabbits. Different doses of ganciclovir ranging from 200 to 600 micrograms/0.1 ml were injected intravitreously, and ERG changes were recorded at different time points after drug administration. Finally the animals were killed and the retinal lesions were studied by electron microscopy. According to our experiments, ganciclovir doses of 300-600 micrograms/0.1 ml have a clearly toxic effect on the retina as shown by ERG changes. One month after the injection, the electroretinogram is either extinguished or clearly affected. Noteworthy is the fact that in a dose of 200 micrograms/0.1 ml, the ERG b-wave shows a 20% reduction of its normal amplitude 4 months after ganciclovir delivery. Electron microscopy of the retina revealed in the inner segment of the receptor cells the existence of dilatation and vesiculation of the endoplasmic reticulum in the surrounding nuclear cytoplasm and swelling of the mitochondria with fragmentation of the cristae in several of them. In the outer segment of the photoreceptor cells, degeneration and destruction of the lamellae accompanied by disintegration of the adjacent protoplasm in parts of certain rods and cones appeared. Finally large vacuoles of irregular shape in the synapses and degenerative mitochondria and empty vacuoles in the optic nerve fibers were shown.

Spontaneous recovery of progressive anterior ischemic optic neuropathy.

During the last 5 years much discussion has occurred about the progressive anterior ischemic optic neuropathy of nonarteretic type and the usefulness of surgical optic nerve sheath decompression for its treatment. The description of cases with spontaneous recovery of the disease made some authors reserved or against this method and the whole subject has been debated with skeptisism. In this article three cases of progressive nonarteretic anterior ischemic optic neuropathy with spontaneous recovery are described. In all these cases visual acuity, as well as visual evoked responses, was spontaneously ameliorated and the optic disc swelling was resolved. Only the visual fields defects remained almost the same. The question arising from this study is whether or not surgical optic nerve sheath decompression in these cases was the only appropriate method of treatment, as some authors propose.

C-wave study in cone dysfunction syndrome.

An electroretinogram (ERG) and C-wave were recorded from 15 patients suffering from cone dysfunction syndrome. Our results show that the photopic ERG was diminished with extinction of the oscillatory potentials. On the other hand, the mean value of the C-wave amplitude was diminished and the implicit time prolonged. This may serve as a further diagnostic sign of the disease.