Sensing device and method of detecting a three-dimensional spatial shape of a body

Abstract

A method for identifying a best fitting shoe includes the steps of scanning a foot using a photogrammetric 3D foot scanner for obtaining a digital 3D model of the foot, and providing a database in which 3D models of shapes of the 5 interiors of available shoes are stored. The 3D model of the digitized foot of the customer is compared with the 3D models of available shoes stored in the database and a shoe of which the 3D model of internal shape is the most similar to the 3D model of the customer foot is selected. The steps of comparing and selecting are performed using a computing unit. A sensing device for detecting a 10 three-dimensional spatial shape of a body includes a sensing end and a camera. A method of detecting a three-dimensional interior spatial shape includes providing the sensing device and scanning the spatial shape.

1 . A sensing device for detecting a three-dimensional spatial shape of a body, comprising a sensing arrangement ( 28 ) which sensing arrangement comprises:
 a sensing end ( 32 ) for scanning a spatial shape to be scanned of a body;   a camera ( 30 );   a connecting device ( 34 ) for rigidly connecting the camera ( 30 ) with the sensing end ( 32 ), the camera ( 30 ) being arranged such that it can detect a surface ( 12 ) which is provided with marks ( 22 ) suitable to be automatically photogrammetrically evaluated and on which the body to be scanned has been placed, while the sensing end ( 32 ) scans different points of the spatial shape to be scanned of the body; and   the sensing device further comprising:   a photogrammetric evaluation program for a computing unit ( 18 ), the computing unit being configured such that image signals generated by the camera ( 30 ) can be routed to the computing unit ( 18 ) and the evaluation program can calculate the 3D coordinates of the spatial shape to be scanned from the sequence of recorded and transmitted image sections using the marks ( 22 ) suitable to be automatically photogrammetrically evaluated.   
     
     
         2 . The sensing device according to  claim 1 , wherein the spatial shape to be scanned of a body ( 26 ) is an inner wall of a hollow body. 
     
     
         3 . The sensing device according to  claim 1 , wherein the camera operates in a video mode and records images continuously. 
     
     
         4 . The sensing device according to  claim 1 , further comprising the surface ( 12 ) provided with marks ( 22 ) suitable to be automatically photogrammetrically evaluated, the exact space coordinates of the marks ( 22 ) being known. 
     
     
         5 . The sensing device according to  claim 4 , wherein an origin of coordinates of the photogrammetrically marked surface ( 12 ) has a trough for accommodating the sensing end ( 32 ). 
     
     
         6 . The sensing device according to  claim 1 , comprising at least two cameras ( 30 ), wherein the cameras are arranged such that a plurality of image sections of the photogrammetrically marked surface ( 12 ) is detected at the same time. 
     
     
         7 . The sensing device according to  claim 1 , wherein the sensing end ( 32 ) exhibits a mechanical and/or optical and/or inductive and/or acoustic contact mechanism which generates a contact signal upon contact with the inner wall. 
     
     
         8 . The sensing device according to  claim 7 , wherein image signals generated by the camera ( 30 ) or the at least two cameras are passed on to the computing unit ( 18 ) or are marked before being passed on to the computing unit only when the contact signal has been generated during recording. 
     
     
         9 . The sensing device according to  claim 1 , wherein the sensing end ( 32 ) comprises an opto-electronic and/or acoustic distance measuring device. 
     
     
         10 . The sensing device according to  claim 1 , wherein the sensing end ( 32 ) comprises a mechanically linearly resiliently displaceable sensing tip having a linear displacement sensor. 
     
     
         11 . The sensing device according to  claim 1 , wherein the sensing device is a supplement to a photogrammetric foot digitizer ( 10 ) which includes a photogrammetrically marked surface ( 12 ) and an image sensor device ( 14 ), the image sensor device ( 14 ) being guided around a body to be digitized, using a holder ( 16 ), and wherein the sensing device comprises a mount which can be connected with the holder ( 16 ) of the image sensor device ( 14 ) of the foot digitizer ( 10 ) and in which the sensing arrangement ( 28 ) can be removably mounted, and the sensing arrangement ( 28 ) being oriented in the mount such that the sensing arrangement only insignificantly conceals the image field of the image sensor device ( 14 ) on the body to be digitized and the photogrammetrically marked surface ( 12 ). 
     
     
         12 . A method of detecting a three-dimensional interior spatial shape of a hollow body, the method comprising the following steps:
 fastening the body ( 26 ) to be digitized on a surface ( 12 ) which, at known positions, is provided with marks ( 22 ) suitable to be automatically photogrammetrically evaluated;   providing a sensing device according to  claim 1 ;   scanning the spatial shape to be detected by means of the sensing end ( 32 ) of the sensing arrangement ( 28 );   recording at least one section of the photogrammetrically marked surface ( 12 ) by the camera ( 30 ) while the sensing end ( 32 ) scans the point, a plurality of marks ( 22 ) suitable to be photogrammetrically evaluated being detected;   repeating the steps of scanning and recording for a multitude of different points of the spatial shape to be detected;   evaluating the recorded images by the evaluation program on a computing unit ( 18 ), the evaluation program determining, by a photogrammetric evaluation of the image sequences, the respective spatial position and the respective orientation of the camera ( 30 ) from the known positions of the photogrammetric marks ( 22 ) detected by the camera ( 30 ) and deriving the respective spatial position of the sensing end ( 32 ) rigidly connected with the camera ( 30 ) from the camera position and camera orientation, and the 3D model of the body ( 26 ), in particular the interior of a hollow body and/or geometric measurements of the interior, being established from the spatial positions of the sensing end ( 32 ) established in this manner.   
     
     
         13 . The method according to  claim 12 , wherein the scanning of the spatial shape is effected in a continuous movement of the sensing end ( 32 ) and wherein the camera ( 30 ) makes recordings continuously in a video mode. 
     
     
         14 . The method according to  claim 12 , wherein the interior spatial shape of the hollow body, in particular of a shoe, is detected, and wherein the camera ( 30 ) remains outside of the hollow body while the interior is scanned. 
     
     
         15 . The method according to  claim 14 , further comprising the following steps:
 determining a convex envelope ( 44 ) of the interior from an overall generated point cloud of coordinates of the interior from established positions;   comparing the established positions of the sensing end ( 32 ) with the convex envelope of the interior;   deleting points of established positions that do not lie on the convex envelope.   
     
     
         16 . The method according to  claim 12 , wherein the sensing end ( 32 ) includes a mechanical and/or optical and/or inductive and/or acoustic contact mechanism which upon contact generates a contact signal, and wherein only those camera images in which the contact signal has been generated are passed on to the computing unit ( 18 ) or are marked before being passed on to the computing unit ( 18 ). 
     
     
         17 . The method according to  claim 12 , wherein the sensing end ( 32 ) disposes of an opto-electronic and/or acoustic distance measurement, and the method further comprises the following steps:
 measuring a distance of the sensing end ( 32 ) from the spatial shape in at least one defined direction;   transferring the measured distance to the computing unit ( 18 ) and calculating a correction vector from the measured distance;   adding the correction vector to the space coordinates of the sensing end ( 32 ) that have been photogrammetrically established from the image recordings of the camera ( 30 ).   
     
     
         18 . The method according to  claim 12 , wherein the sensing end ( 32 ) disposes of a mechanically linearly resiliently displaceable sensing tip having a linear displacement sensor, and the method further comprises the following steps:
 transferring a displacement signal from the linear displacement sensor to the computing unit ( 18 ) upon contact of the sensing tip with the inner wall and calculating a correction vector from the displacement signal;   adding the correction vector to the space coordinates of the sensing end ( 32 ) that have been photogrammetrically established from the image recordings of the camera ( 30 ).   
     
     
         19 . The method according to  claim 12 , wherein the method further comprises the following calibration steps:
 placing the sensing end ( 32 ) on a defined point, preferably an origin of coordinates of the photogrammetrically marked surface ( 12 );   moving the camera ( 30 ) on a spherical surface around this point, the sensing end ( 32 ) remaining in contact with the photogrammetrically marked surface ( 12 ) during the movement;   recording a sequence of images during the movement and passing it on to the computing unit ( 18 );   calculating the relative position of the sensing end ( 32 ) in relation to the origin of coordinates of the image sensor of the camera ( 30 ) as well as the internal parameters of the camera ( 30 ) from the sequence of images recorded by the camera.   
     
     
         20 . The method according to  claim 12 , wherein the scanned spatial shape is the interior of a body ( 26 ) that has been deformed by use and/or stress, and wherein the calculated 3D model and/or the calculated geometric measurements of this interior deformed by use is/are made use of for selecting and/or manufacturing a new body. 
     
     
         21 . The method according to  claim 12 , wherein the spatial shape to be scanned pertains to any one of the following bodies:
 a footwear;   a headgear and/or a headguard;   a covering for clothing and/or protecting the human or animal body;   an orthopedic and/or prosthetic product having an interior that is open to the outside and presents a spatial surface area to be adjusted to an anatomy of a patient requiring orthopedic and/or prosthetic care.   
     
     
         22 . The method according to  claim 12 , wherein the sensing arrangement is mechanically moved by a motor drive such that the sensing end ( 32 ) contacts as many points as possible of the interior of the body. 
     
     
         23 . A method for identifying a best fitting shoe, the method comprising the steps of:
 scanning a foot of a customer using a photogrammetric 3D foot scanner for obtaining a digital 3D model of the foot;   providing a database in which 3D models of shapes of the interiors of available shoes are stored;   comparing the 3D model of the digitized foot of the customer with the 3D models of available shoes stored in the database;   selecting a shoe of which the 3D model of internal shape is the most similar to the 3D model of the customer foot:   wherein the comparing and selecting steps are performed using a Computing unit.   
     
     
         24 . The method of  claim 23 , wherein the database contains digital 3D models of internal shapes of shoes produced by shoe manufacturers organized in a business alliance. 
     
     
         25 . The method of  claim 23 , wherein the 3D models of shapes of the interiors of available shoes are obtained by scanning nondestructively the spatial inner shape by means of a sensing arrangement, the sensing arrangement comprising a sensing end which is moved inside the shoe and a camera which is connected rigidly to the sensing end in such a way that the camera remains outside the shoe during scanning.