# US 8,542,368 B2 · Position measuring apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,368 B2 - Document ID: US8542368B2 - Status: Granted - Kind: B2 - Application number: 13/310,598 - Filed: 2011-12-02 - Published: 2012-06-21 - Granted: 2013-09-24 - Earliest claimed: 2010-12-17 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Dae Ho Kim; Tae-Gyu Kang; Sang-Kyu Lim; Il-Soon Jang; You Jin Kim - Inventors: Dae Ho Kim; Tae-Gyu Kang; Sang-Kyu Lim; Il-Soon Jang; You Jin Kim - Web page: https://patentgrep.com/patent/US8542368B2 ## CPC - G01S 11/12: using electromagnetic waves other than radio waves - G01S 5/16: using electromagnetic waves other than radio waves - G01S 5/163: {Determination of attitude (using inertial means G01C9/00; control of attitude G05D1/49)} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A position measuring apparatus receives at least one precise position information set from at least one visible-light wireless communication device including a transmission light source, and upon receipt of the at least one precise position information ser, acquires a virtual distance based on the positions of transmission light sources imaged on an image sensor. Next, the position is measured according to the precise position information and the actual distance, virtual distance, and image sensor inclination based on this information. ## Claims ### Claim 1 A position measuring method, which measures a position based on information provided from at least one communication device including a transmission light source, the method comprising: acquiring precise position information indicating a position of the transmission light source by capturing an image including an optical signal transmitted from the transmission light source; calculating an actual light source distance between transmission light sources based on the precise position information; calculating a virtual light source distance between the transmission light sources imaged on the image sensor from the captured image; measuring inclination of the image sensor; and measuring a position based on the actual light source distance, the virtual light source distance, and the inclination, wherein the position measuring comprises: calculating a first virtual light source distance between the transmission light sources imaged on the image sensor, and a second virtual light source distance corresponding to a parallel state of the image sensor based on the inclination; and calculating the position based on the second virtual light source distance, the actual light source distance, and the received precise position information about each transmission light source. ### Claim 2 (depends on 1) The method of claim 1, wherein the position calculating comprises: calculating a first virtual distance to one transmission light source imaged on the image sensor from a central point of the image sensor based on the second virtual light source distance; calculating a second virtual distance to another transmission light source imaged on the image sensor from the central point of the image sensor based on the second virtual light source distance; and calculating the position based on the first virtual distance, the second virtual distance, the actual light source distance, and the precise position information. ### Claim 3 (depends on 2) The method of claim 2, wherein, in the position calculating, the position is calculated based on the first virtual distance and the second virtual distance that are proportional to a first distance and a second distance, the first distance corresponding to a distance from a position of one transmission light source to a position to be measured based on the precise position information, and the second distance corresponding to a distance from a position of another transmission light source to the position to be measured based on the precise position information. ### Claim 4 (depends on 3) The method of claim 3, wherein the position calculating comprises: calculating the first distance based on a condition d1=(d1+d2)×sd1/(sd1+sd2) (where d1 represents the first distance, d2 represents the second distance, sd1 represents the first virtual distance, and sd2 represents the second virtual distance); and calculating the position according to the position of one transmission light source based on the precise position information and the first distance. ### Claim 5 (depends on 4) The method of claim 4, wherein, if the position of one transmission light source based on the precise position information is a coordinate x1 on an X axis, a coordinate of the position to be measured corresponds to a coordinate of x1+ the first distance. ### Claim 6 (depends on 1) The method of claim of claim 1, wherein, if the position is measured on a two-dimensional plane using X and Y axes, the precise position information comprises coordinates along the X and Y axes, and X-axis and Y-axis coordinates of the measurement position are obtained by performing, for each of the X and Y axes, the acquiring of precise position information, the calculating of an actual light source distance, the calculating of a virtual light source distance, the measuring of an inclination, and the measuring of a position. ### Claim 7 A position measuring method, which measures a position based on information provided from at least one communication device including a transmission light source, the method comprising: acquiring precise position information indicating a position of the transmission light source by capturing an image including an optical signal transmitted from the transmission light source with an image sensor, the precise position information including coordinates along X and Y axes on a two-dimensional plane using the X and Y axes; if the precise position information is received from at least two transmission light sources, calculating an actual light source distance between the transmission light sources on each of the X and Y axes based on the precise position information; calculating a virtual light source distance between the transmission light sources on each of the X and Y axes, imaged on the image sensor, from the captured image; measuring inclination of the image sensor along each of the X and Y axes; calculating a parallel virtual light source distance on each of the X and Y axes, corresponding a parallel state of the image sensor, based on the virtual light source distance and the inclination; and measuring a position of a measurement object on each of the X and Y axes based on the measured actual light source distance, parallel virtual light source distance, the inclination, and the precise position information. ### Claim 8 (depends on 1) The method of claim 1, wherein the position measuring comprises: calculating a first virtual light source distance to one transmission light source imaged on the image sensor from a central point of the image sensor along each of the X and Y axes based on the parallel virtual light source distance; calculating a second virtual distance to another transmission light source imaged on the image sensor from the central point of the image sensor along each of the X and Y axes based on the parallel virtual light source distance; calculating a first distance and a second distance for each of the X and Y axes based on the first and second virtual distances, the first distance corresponding to a distance to a measurement position from a position of one transmission light source based on the precise position information, and the second distance corresponding to a distance to the measurement position from a position of another transmission light source based on the precise position information; and measuring a position of the object on the X and Y axes based on the first distance, the second distance, and the precise position information regarding the transmission light sources. ### Claim 9 (depends on 2) The method of claim 2, further comprising: converting the first and second distances into actual distances, wherein, in the position measuring, the position is measured using the converted first and second distances. ### Claim 10 A position measuring apparatus, which measures a position based on information provided from at least one communication device including a transmission light source, the apparatus comprising: a position information receiver that acquires precise position information indicating a position of the transmission light source by capturing an image including an optical signal transmitted from the transmission light source with an image sensor, the precise position information including coordinates along X and Y axes on a two-dimensional plane using the X and Y axes; an actual light source distance measuring unit that calculates an actual light source distance between transmission light sources on each of the X and Y axes based on the precise position information; a virtual light source distance measuring unit that calculates a virtual light source distance between the transmission light sources on each of the X and Y axes, imaged on the image sensor, from the captured image; an inclination measuring unit that measures an inclination of the image sensor along each of the X and Y axes; and a position information processing unit that measures a position of a measurement object on the X and Y axes based on an actual light source distance, a virtual light source distance, and inclination measured for each of the X and Y axes and the precise position information, wherein the position information processing unit calculates a parallel virtual light source distance for each of the X and Y axes, corresponding to a parallel state of the image sensor, based on the virtual light source distance and the inclination, and calculates the position based on the parallel virtual light source distance, the actual light source distance, and the precise position information about each transmission light source. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the position information processing unit comprises: a distance measuring module that calculates the parallel virtual light source distance for each of the X and Y axes, corresponding to the parallel state of the image sensor, based on the virtual light source distance and the inclination, and calculates a first distance and a second distance for each of the X and Y axes based on the parallel virtual light source distance, the first distance corresponding to a distance to a measurement position from a position of one transmission light source based on the precise position information, and the second distance corresponding to a distance to the measurement position from a position of another transmission light source based on the precise position information; and a position calculation module that measures a position of the object on the X and Y axes based on the first distance, the second distance, and the precise position information regarding the transmission light sources. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the position calculation module calculates the position based on the fact that the first and second virtual distances calculated based on the parallel virtual light source distance are proportional to the first and second distances, the first virtual distance corresponding to a distance to the one transmission light source imaged on the image sensor from the central point of the image sensor, and the second distance corresponding to a distance to the another transmission light source imaged on the image sensor from the central point of the image sensor. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the position information processing unit further comprises a distance conversion module for converting the first and second distances into actual distances. ### Claim 14 (depends on 10) The apparatus of claim 10, further comprising a processing method selection unit that selects either a first method or a second method depending on a number of the received precise position information sets, wherein the first method is to measure position based on the received precise position information, and the second method is to measure position using the received precise position information and a given central point of the image sensor.