: The field of picture processing by computer is reviewed from a technique-oriented standpoint. Only the processing of given pictures (as opposed to computer-synthesized pictures) is considered. Specific areas covered include: (a) Pictures as information sources and their efficient encoding; (b) Approximation of pictures - sampling and quantization techniques; (c) Position-invariant operations on pictures and their implementation (digital, electro-optical, optical); applications to matched filtering (template matching), spatial frequency filtering and image restoration, measurement of image quality, and image enhancement ('smoothing' and 'sharpening'); (d) Picture properties (linear; local and 'textural'; random) useful for pictorial pattern recognition; (e) 'Figure extraction' from pictures; figure properties (topology, size, shape); (f) Picture description and 'picture languages.' (Author)

Picture processing by computer

A new computer language for electron image processing

In attempting to assess the possibilities of mapping from earth satellites, various factors which do not occur with aerial photography must be considered. The orbital characteristics of satellites are discussed from the point of view of their effects on photographic scale and coverage and the problems of taking and retrieving photography from satellites are outlined. An evaluation of the possibilities and limitations of mapping from both single and stereoscopic television pictures and normal frame photography is made and the tentative conclusion reached that topographic mapping from earth satellite photography may only be considered seriously for the scales 1 : 250 000 to 1 : 1 000 000 and for a minimum contour interval of 100 m. The economy of this very small-scale mapping is at present very doubtful in view of the current costs of building and launching a suitable satellite. Any extensive programme of satellite photography for mapping purposes could pose some difficult legal and political problems if the photography was made freely available.

Resume

L'auteur etudie les caracteres des satellites artificiels du point de vue de leur emploi dans la photographie aerienne. II traite aussi de l'emploi de la photographie prise des satellites pour la photogrammetrie et conclue provisoirement qu'elle ne pourrait servir comme base que pour les cartes aux echelles moins de 1 : 250 000 port antes des courbes de niveau de 100 m en 100 m a moins. Il est tres douteux que l'emploi des satellites pour de tels travaux puisse etre econome, et leur emploi general posera de forts problemes legaux.

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Some considerations regarding mapping from earth satellites

This investigation is a part of a continuing research program studying the potential of television-waveform instrumentation in identifying, analyzing, and mapping geographic phenomena recorded in aerial and space imagery. Research objectives included: (1) Effectiveness of converting aerial color and color infrared imagery to electronic scanning returns with an ultimate goal of providing a graphic and quantitative method for analyzing the geographic data recorded on the above two imagery types; (2) Effectiveness of manually transposing waveform information recorded from a systematic sampling by scan traverse lines into representative numbers (expressed as percentages) that reveal geographic phenomena and developing a computer program to manipulate the geographic data in several ways; and (3) To reveal new facets of research that could be an outgrowth of this investigation, and to evaluate the study as a contribution to geography. Results indicated that the television-waveform system offers positive potential for the quantitative analysis of geographic distributions found on aerial color and color infrared photography. Phenomena colors were segregated on both the above film types, but identifying waveforms extracted from the former type offered optimum results. Waveform results from high altitude (15,000 feet) and orbital color photography also indicated positive results in the identification of geographic distributants. A direct correlation, however, does exist as the scale of the photography decreases the degree of categorization becomes more generalized. With geographic information in the form of digits (graytone percentages) a computer program was developed to identify, analyze', and map the coded information. Computer analysis of graytone digital data revealed very positive findings. Additional discussion noted equipment additions which could be incorporated into the television-waveform system to more fully automate computer input information.

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Waveform and computer analysis of geographic phenomena recorded on color and color infrared multispectral imagery from aerial and orbital altitudes

TV picture storing, processing and displaying technique by digital computer to aid photointerpreter in diagnosing image

E. Efron

Papers

Image processing by digital systems.