Method, device and computer programme for extracting information about one or more spatial objects

1. A method for the extraction of information about a staircase and for making a stair handrail or a stair lift comprising a guide which is installed at the staircase and along which a frame on which a person can be seated can move, wherein the method comprises:

placing a plurality of markers on or near the staircase;

moving a device along the staircase with the markers, wherein the device comprises:

a central processing unit which is loaded with a computer programme;

a digital memory which is connected to the central processing unit;

a camera which is capable of recording a sequence of images; and

output means which are connected to the central processing unit, and

recording a sequence of images of said staircase with said markers with the camera;

analyzing the sequence of images using image analysis techniques in real time while the device is being moved along the staircase;

extracting information about said staircase comprising at least information about a spatial position of the plurality of markers in real time while the device is being moved along the staircase;

calculating an indication as to then realized accuracy of the extracted information about a spatial position of the plurality of markers in real time;

communicating said indication in real time via the output means in real time while the device is being moved along the staircase; and

calculating dimensions of a plurality of parts of the stair handrail or of the guide of the stair lift using the extracted spatial position of the plurality of the markers.

2. A method according to claim 1 , wherein said markers are placed on or near said staircase before a sequence of images is recorded by means of the device, which markers have a shape such that they can take up a detectable spatial orientation in the images, and wherein the computer programme determines the spatial position and orientation of the markers on the basis of the markers detected in the images and/or of prominent elements detected in the images, and uses the information of the thus determined position and orientation of the markers during the recording of each of the images upon extracting the aforesaid information about said staircase.

3. A method according to claim 1 , wherein the image analysis techniques comprise an AR marker tracking algorithm and a Simultaneous Localisation and Mapping (SLAM) algorithm for determining the spatial locations of the markers and of the camera during the recording of each of the images; and

wherein the image analysis techniques comprise an algorithm based on epipolar geometry, for determining the spatial position of at least two prominent points of said one or more objects, wherein the positions of the camera during the recording of each of the images as determined by the SLAM algorithm are also used as input of the algorithm.

4. A method according to claim 1 , wherein the programme stores at least part of the information in the digital memory.

5. A method according to claim 1 , wherein the programme stores coordinates of the aforesaid spatial position of said staircase in the digital memory.

6. A method according to claim 1 , wherein the indication is an acoustic and/or visual signal.

7. A method according to claim 1 , wherein the device further comprises a display screen, and wherein the indication about the obtained realized accuracy comprises an object generated by the central processing unit, said object being in the form of a hand rail or a guide rail for a stair lift, which is to an increasingly stable degree shown overlapping a current image from the camera of the staircase, on the display screen.

8. A method according to claim 3 , wherein the SLAM algorithm is carried out by one of the following available or comparable tools:

parallel tracking and multiple mapping (PTAMM) from the Active Vision Group of Oxford University, United Kingdom; or

the SLAM implementation from 13th Lab, Sweden.

9. A method according to claim 3 , wherein the AR marker tracking algorithm is carried out by the following or comparable tool:

OpenCV (Open Source Computer Vision).

10. A method according to claim 1 , wherein said device is a tablet computer or a smartphone.

11. A method according to claim 1 , wherein the device comprises an acceleration sensor and/or gyroscope, which is connected to the central processing unit, and wherein the programme determines, based on information from the acceleration sensor and/or gyroscope, whether the camera is stationary in the space, and records an image from the camera in the sequence of images at that moment.