Photogrammetric method

Claim 1

A method for deriving and storing information about industrial plant structures constructed of a plurality of interrelated, three-dimensional, basic unit shapes, the method comprising: (a) taking stereo-pair photographs of the structure, (b) mounting the photographs in a photogrammetry stereo comparator including a co-ordinate readout, a data base, and processing means for processing information in accordance with said data base, (c) effecting orientation procedures to correlate comparator coordinates to the orientation of the structure, (d) providing the processing means with a mathematical template for each kind of basic unit shape for which the information is required, each template having variable parameters defining the dimensions and orientation of the shape, said parameters being initialized to nominal values, (e) selecting a first template corresponding to a first unit shape and entering this first template into the data base, (f) selecting a further template corresponding to a first unit shape and entering this further template into the data base, (g) repeating step (f) until templates are entered into the data base for each basic unit shape about which information is required, (h) specifying in the data base the manner in which the basic unit shapes for which templates are provided are interconnected, (i) viewing through the stereo comparator a first basic unit shape depicted in the stereo-pair photographs and selecting a corresponding template, (j) aligning the comparator with a plurality of points on the viewed basic unit shape in turn and operating the comparator readout means to obtain the co-ordinates of those points, (k) calculating from the readout co-ordinates the true values for the variable parameters of the corresponding template, and replacing the nominal initial values with these calculated true values, and (l) repeating steps (i) (j) and (k) for each template selected thereby to obtain the values of the parameters for each basic unit shape and their three-dimensional interrelation in the structure.

Claim 2

A method for deriving and storing information about industrial plant structures constructed of a plurality of interrelated, three-dimensional, basic unit shapes, the method comprising: (a) taking stereo-pair photographs of the structure, (b) mounting the photographs in a photogrammetry stereo comparator including a co-ordinate readout, a data base, and processing means for processing information in accordance with said data base, (c) effecting orientation procedures to correlate comparator coordinates to the orientation of the structure, (d) providing the processing means with a mathematical template for each kind of basic unit shape for which the information is required, each template having variable parameters defining the dimensions and orientation of the shape, said parameters being initialized to nominal values, (e) selecting a first template corresponding to a first unit shape and entering this first template into the data base, (f) selecting a further template corresponding to a first unit shape and entering this further template into the data base, (g) repeating step (f) until templates are entered into the data base for each basic unit shape about which information is required, (h) specifying in the data base the manner in which the basic unit shapes for which templates are provided are interconnected, (i) viewing through the stereo comparator a first basic unit shape depicted in the stereo-pair photographs and selecting a corresponding template, (j) aligning the comparator with a plurality of points on the viewed basic unit shape in turn and operating the comparator readout means to obtain the co-ordinates of those points, (k) calculating from the readout co-ordinates the true values for the variable parameters of the corresponding template, and replacing the nominal initial values with these calculated true values, and (l) repeating steps (i) (j) and (k) for each template selected thereby to obtain the values of the parameters for each basic unit shape and their three-dimensional interrelation in the structure.

Claim 6

A method as claimed in any one of the preceding claims in which the data base is interfaced with a graphics apparatus, to enable the interrelated basic unit shapes to be displayed graphically.

Claim 9

A method as claimed in any one of claims 1 or 7 further including the steps of: (1) selecting a new template corresponding to a new basic unit shape to be added and entering it into the data base with nominal values for the variable parameters associated therewith, (2) repeating step (1) until a new template has been entered into the data base for each new basic unit shape to be added, (3) specifying in the data base the manner in which the new basic unit shapes for which templates are provided, are to be interconnected to the existing unit shapes defined previously by said steps (e) or (f), and (4) entering, for each new template, true parameter values which define in each case a new basic unit shape which occupies a space not occupied or overlapped by any of the other basic unit shapes in the data base.