Computer arrangement for and method of matching location data of different sources
A computer arrangement is disclosed, including a processor and a memory that stores a computer program, object data originating from a first source and including object location data, and laser samples originating from a second source, including a sub-set of laser samples relating to the object and including laser sample location data as to each laser sample. In at least one embodiment, the processor compares the object location data and the laser sample location data of the sub-set of laser samples, and matches the object location data to the laser sample location data of the sub-set of laser samples based on this comparison, and thereby corrects for relative positional errors between the first and second sources of location data. The object may be a building façade, for example.
1. A method of aligning building block footprint data and laser samples, comprising:
accessing stored location data associated with a building block footprint originating from a first source;
accessing a plurality of stored sweeps of laser samples originating from a second source, each sweep of laser samples being oriented perpendicular to the earth plane and having locations associated with the reflection of a laser beam against a solid object and relative to one of a plurality of geo-reference points;
selecting a subset of the laser samples for each of the stored sweeps relating to a façade of the building block footprint;
projecting the locations associated with the subset for each of the stored sweeps of laser samples to the earth plane to obtain a plurality of estimated edge points of the façade of the building block footprint;
calculating a shift vector for each estimated edge point that when applied, shift the estimated edge points to coincide with the portion of the building block footprint data representative of the façade, wherein the shift vector is a vector projected from the estimated edge point to the nearest point on the building block footprint edge; and
using said shift vectors to align the laser sample location data to the building block footprint location data.
2. The method of claim 1 , wherein said selecting a subset of laser samples from each of the stored sweeps relating to the façade of the building block footprint comprises:
creating line segments by connecting adjacent laser sample locations;
identifying and grouping those line segments that are substantially collinear with other line segments and that extend substantially perpendicular to the earth;
determining a length from the point nearest to the earth plane to the point farthest from the earth plane of the points used to create each group of line segments; and
identifying the laser samples related to the façade as those used to create the line segments making up the group with the longest determined length.
3. The method of claim 2 , wherein said projecting the locations associated with the subset of laser samples for each stored sweep related to the façade of the building block footprint, to the earth plane to obtain a plurality of estimated edge points of the façade of the building block footprint comprises vertically projecting the locations associated with the selected laser samples to the earth plane to obtain a plurality of projection points, and calculating a median of the projection points to obtain an estimated edge point.
4. The method according to claim 1 , further comprising accessing stored photographic pictures including texture information of said building façade, the photographic pictures originating from a third source having a known location in relation to the second source, and using said shift vectors to provide said building façade with said texture information.
5. A non-transitory computer readable medium containing software that when executed on a computer arrangement causes the computer arrangement to perform the method of claim 1 .
6. Computer arrangement, comprising a memory and a processor arranged to communicate with the memory, the memory storing a computer program including instructions and data that can be run by the processor, and storing location data associated with a building block footprint originating from a first source and sweeps of laser samples oriented perpendicular to the earth plane, and originating from a second source, each sweep of laser samples having a location relative to one of a plurality of geo-reference points and associated with the reflection of a laser beam against a solid object, said computer program run on the processor being arranged to:
access stored location data associated with a building block footprint;
access a plurality of stored sweeps of laser samples;
select a subset of the laser samples for each of the stored sweeps relating to a façade of the building block footprint;
project the locations associated with the subset for each of the stored sweeps of laser samples to the earth plane to obtain a plurality of estimated edge points of the façade of the building block footprint;
calculate a shift vector for each estimated edge point that when applied shift the estimated edge points to coincide with the portion of the building block footprint representative of the façade, wherein the shift vector is a vector projected from the estimated edge point to the nearest point on the building block footprint edge; and
use said shift vectors to align the laser sample location data to the building block footprint location data.