Showing papers by "Azriel Rosenfeld published in 1971"
TL;DR: Simple sets of parallel operations are described which can be used to detect texture edges, "spots," and "streaks" in digitized pictures and it is shown that a composite output is constructed in which edges between differently textured regions are detected, and isolated objects are also detected, but the objects composing the textures are ignored.
Abstract: Simple sets of parallel operations are described which can be used to detect texture edges, "spots," and "streaks" in digitized pictures. It is shown that, by comparing the outputs of the operations corresponding to (e.g.,) edges of different sizes, one can construct a composite output in which edges between differently textured regions are detected, and isolated objects are also detected, but the objects composing the textures are ignored. Relationships between this class of picture processing operations and the Gestalt psychologists' laws of pictorial pattern organization are also discussed.
811 citations
TL;DR: It is proved that several algorithms which perform a thinning transformation when applied to the picture in parallel do not change the connectivity properties of the picture.
Abstract: If a picture contains elongated objects of different thicknesses, one can make measurements on it which are thickness-invariant by first transforming it so that each object is thinned down to a \"medial line\" of constant thickness. Several algorithms are described which perform such a thinning transformation when applied to the picture in parallel. It is proved that these algorithms do not change the connectivity properties of the picture.
278 citations
Proceedings Article•
01 Sep 1971
TL;DR: Finite automata having two-dimensional tapes are much less well-behaved than their one-dimensional counterparts and it appears to be difficult to define a natural class of array grammars that is equal in power to any of these types of array automata.
Abstract: : Finite automata having two-dimensional tapes are much less well-behaved than their one-dimensional counterparts. In particular, for such automata, one-way is weaker than two-way, array-bounded is weaker than non-array-bounded, and deterministic is weaker than nondeterministic. It also appears to be difficult to define a natural class of array grammars that is equal in power to any of these types of array automata; all of the definitions formulated thus far either have the wrong power or have some degree of artificiality. (Author)
88 citations
01 May 1971
TL;DR: Algorithms are presented for labeling connected objects in a binary three-dimensional array, for counting such objects, and for computing the genus of the array.
Abstract: Algorithms for labeling, counting, and computing connected objects in binary three dimensional array
38 citations
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TL;DR: This chapter describes a grammar for maps whose sentences are not strings of symbols, but rather sets of symbols that can be interconnected in more general ways, are of importance in connection with the formal theory of picture processing and description.
Abstract: Publisher Summary This chapter describes a grammar for maps. Grammars whose sentences are not strings of symbols, but rather sets of symbols that can be interconnected in more general ways, are of importance in connection with the formal theory of picture processing and description. One of the most general formalisms of this kind deals with sentences, which are labeled directed graphs, that is, webs. Webs arise naturally in connection with descriptions of pictures; a description can present the relations among objects or regions in the given picture, so that it can be represented by a web whose vertices represent regions and whose edges indicate related pairs of regions. As pictures are planar, the webs that arise in this way can mostly be planar. When a graph is used to represent the adjacency relation between regions in the plane, not all of the topological information about the regions is preserved.
26 citations
TL;DR: Scattered context Grammars can be regarded as web grammars in which the web is the transitive closure of string, and it is shown that if 'negative context' is allowed, they are as strong as context-sensitivegrammars.
22 citations
01 Jan 1971
TL;DR: A method of converting a picture into a "cartoon" or "map" whose regions correspond to differently textured regions is described, which has been applied to the construction of cloud cover maps from cloud cover pictures obtained by satellites.
Abstract: A method of converting a picture into a "cartoon" or "map" whose regions correspond to differently textured regions is described. Texture edges in the picture are detected, and solid regions surrounded by these (usually broken) edges are "colored in" using a propagation process. The resulting map is cleaned by comparing the region colors with the textures of the corresponding regions in the picture, and also by merging some regions with others according to criteria based on topology and size. The method has been applied to the construction of cloud cover maps from cloud cover pictures obtained by satellites.
2 citations
01 Aug 1971
TL;DR: The first part discusses the idea of iterating the conversion of a continuous-tone picture from binary to gray code representation and the resulting rearrangement of grey levels as well as that of the bits throughout the planes is discussed.
Abstract: : The report consists of two independent parts. The first part discusses the idea of iterating the conversion of a continuous-tone picture from binary to gray code representation. A simple recursive function is defined by means of which the value of the ith bit representing a picture point's grey level after the mth iteration is determined. The resulting rearrangement of grey levels as well as that of the bits throughout the planes is discussed. The second part of the report contains information regarding the high-resolution digital picture output system developed at the University of Maryland. (Author)
1 citations