Work information projection system and relative information calibration method

1 . A work information projection system, comprising:

a projector that projects an auxiliary image that assists work onto a workplace;

a camera that captures the workplace;

a memory; and

a controller, connected to the memory, that creates the auxiliary image and transmits it to the projector,

wherein, during a calibration process of calibrating relative information that indicates a relative positional relation between the camera and the projector:

the camera captures a calibration image projected by the projector onto a calibration jig through a reflector, and

the controller performs the calibration process of calibrating the relative information based on the calibration image captured by the camera,

wherein a direction that the reflector faces in is changeable, and

wherein the direction that the reflector faces in is changeable between a first direction with which the camera can capture the calibration image projected by the projector and a second direction with which the camera cannot capture the auxiliary image projected by the projector.

2 . The work information projection system according to claim 1 , wherein, during the work when the auxiliary image is projected onto the workplace:

the controller estimates a position of the camera based on an image captured by the camera,

the controller estimates a position of the projector based on the relative information and the position of the camera, and

the controller controls the projector based on the position of the projector to project the auxiliary image onto the workplace.

3 . The work information projection system according to claim 1 , wherein:

the camera moves integrally with the projector.

4 . The work information projection system according to claim 1 , wherein:

during the work when the auxiliary image is projected onto the workplace, a direction of an optical axis of the camera is different from a direction of an optical axis of the projector.

5 . The work information projection system according to claim 4 , wherein:

during the work, the optical axis of the camera is not included in a range in which the projector can project projection light.

6 . The work information projection system according to claim 1 , further comprising:

a driver that generates power to change the direction that the reflector faces in,

wherein, during the work when the auxiliary image is projected onto the workplace;

the camera captures the workplace through the reflector, and

the controller changes the direction that the reflector faces in by controlling the driver when it determines that a number of feature points included in an image captured by the camera becomes less than a threshold.

7 . The work information projection system according to claim 6 , wherein:

the driver is a motor including an output shaft with a controllable amount of rotation, and

the work information projection system further comprises an encoder attached to a mount of the reflector to detect a rotation angle of the mount.

8 . The work information projection system according to claim 1 , wherein an optical axis of the camera is upward or downward with respect to a plane perpendicular to a vertical direction.

9 . The work information projection system according to claim 1 , wherein:

a marker is attached to the reflector, and

the image captured by the camera includes the marker.

10 . The work information projection system according to claim 1 , further comprising:

a cart including wheels and a base,

wherein the projector and the camera are placed on the base.

11 . A work information projection system, comprising:

a projector that projects an auxiliary image that assists work onto a workplace;

a camera that captures the workplace;

a memory; and

a controller, connected to the memory, that creates the auxiliary image and transmits it to the projector,

wherein, during a calibration process of calibrating relative information that indicates a relative positional relation between the camera and the projector;

the camera captures a calibration image projected by the projector onto a calibration jig through a reflector, and

the controller performs the calibration process of calibrating the relative information based on the calibration image captured by the camera,

wherein:

the camera captures the calibration image through the reflector during the calibration process, and

the camera captures the workplace without the reflector during the work when the auxiliary image is projected onto the workplace.

12 . The work information projection system according to claim 11 , wherein during the work when the auxiliary image is projected onto the workplace:

the controller estimates a position of the camera based on an image captured by the camera,

the controller estimates a position of the projector based on the relative information and the position of the camera, and

the controller controls the projector based on the position of the projector to project the auxiliary image onto the workplace.

13 . The work information projection system according to claim 11 , wherein:

the camera moves integrally with the projector.

14 . The work information projection system according to claim 11 , wherein:

during the work when the auxiliary image is projected onto the workplace, a direction of an optical axis of the camera is different from a direction of an optical axis of the projector.

15 . The work information projection system according to claim 14 , wherein:

during the work, the optical axis of the camera is not included in a range in which the projector can project projection light.

16 . A work information projection system, comprising:

a projector that projects an auxiliary image that assists work onto a workplace;

a camera that captures the workplace;

a memory; and

a controller, connected to the memory, that creates the auxiliary image and transmits it to the projector,

wherein, during a calibration process of calibrating relative information that indicates a relative positional relation between the camera and the projector;

the camera captures a calibration image projected by the projector onto a calibration jig through a reflector, and

the controller performs the calibration process of calibrating the relative information based on the calibration image captured by the camera,

wherein, during the calibration process:

the controller calculates a positional relation between the camera and the reflector based on the reflector included in an image captured by the camera,

the controller calculates a positional relation between the camera and a virtual camera based on the positional relation between the camera and the reflector, and

the controller calculates a positional relation between the projector and the virtual camera based on the calibration image reflected in the reflector and calibrates the relative information.

17 . The work information projection system according to claim 16 , wherein during the work when the auxiliary image is projected onto the workplace:

the controller estimates a position of the camera based on the image captured by the camera,

the controller estimates a position of the projector based on the relative information and the position of the camera, and

the controller controls the projector based on the position of the projector to project the auxiliary image onto the workplace.

18 . The work information projection system according to claim 16 , wherein:

the camera moves integrally with the projector.

19 . The work information projection system according to claim 16 , wherein:

during the work when the auxiliary image is projected onto the workplace, a direction of an optical axis of the camera is different from a direction of an optical axis of the projector.

20 . The work information projection system according to claim 16 , wherein:

an optical axis of the camera is upward or downward with respect to a plane perpendicular to a vertical direction.