Determining position in a projection capture system
AssigneeHewlett-Packard Development Company, L.P.
InventorsRobert D Blanton, Otto K Sievert, Hamadi Jamali, David Bradley Short
Life of this patent
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Abstract
In one example, a projection capture system includes: a visible light projector to project a pattern on to a surface of a GUI control object placed on or above a work surface; a visible light camera to capture an image of the pattern projected on to the surface of the control object; and a controller operatively connected to the projector and the camera. Programming on the controller determines (1) a lateral position of the pattern relative to a reference position associated with the work surface based on the pattern image captured by the camera and (2) a height of the pattern above the work surface based on the lateral position of the pattern.
Claims12
A projection capture system for use with a horizontal work surface, comprising:
- a single visible light projector to project a pattern on to a surface of a GUI control object placed on or above the work surface;
- a single visible light camera positioned with respect to the projector such that a pattern projected into a camera light path shifts laterally within the camera light path as a function of the height of the pattern above the work surface, the camera to capture an image of the pattern projected on to the surface of the control object and detect a lateral shift in the pattern relative to a reference position associated with the work surface;
- and
- a controller operatively connected to the projector and the camera, the controller having programming thereon that when executed computes a height of the pattern above the work surface as a function of lateral shift detected by the camera according to the equation H(S)=S÷(tan β−tan α) where:
- S is the lateral shift of the pattern in the camera light path;
- β is an interior angle of a right triangle FDC in which FD is a height of the camera above the work surface and DC is a lateral distance along the work surface in a direction of camera shift between the camera and an edge of the pattern;
- and
- α is an interior angle of a right triangle ABC in which AB is an effective height of the projector and BC is a lateral distance along the work surface in a direction of projector shift between an effective position of the projector and the edge of the pattern.
A non-transitory processor executable medium including programming thereon that when executed:
- causes a projector to simultaneously project a GUI into a work space that includes a reference surface and a pattern on to a surface of a GUI control object placed on or above the reference surface;
- causes a camera to capture an image of the pattern;
- based on the pattern image, determines a lateral shift of the pattern relative to a reference position on the reference surface;
- and
- based on the lateral shift of the pattern, determines a height of the pattern above the reference surface according to the equation H(S)=S÷ (tan β−tan α) where:
- S is a lateral shift of the pattern in a camera light path;
- β is an interior angle of a right triangle FDC in which FD is a height of the camera above the reference surface and DC is a lateral distance along the reference surface in a direction of camera shift between the camera and an edge of the pattern;
- and
- α is an interior angle of a right triangle ABC in which AB is an effective height of the projector and BC is a lateral distance along the reference surface in a direction of projector shift between an effective position of the projector and the edge of the pattern.
A method, comprising:
- projecting a pattern on to a surface of an object;
- capturing an image of the pattern with a camera;
- based on the pattern image, determining a lateral shift of the pattern relative to a reference position;
- and
- based on the lateral shift of the pattern, determining a height of the pattern above a reference surface associated with the reference position according to the equation H(S)=S÷ (tan β−tan α) where:
- S is a lateral shift of the pattern in a camera light path;
- β is an interior angle of a right triangle FDC in which FD is a height of the camera above the reference surface and DC is a lateral distance along the reference surface in a direction of camera shift between the camera and an edge of the pattern;
- and
- α is an interior angle of a right triangle ABC in which AB is an effective height of the projector and BC is a lateral distance along the reference surface in a direction of projector shift between an effective position of the projector and the edge of the pattern.
Dependencies are inferred from the claim text.