Fixed-element digital-optical measuring device
AssigneeOcula Corporation
InventorRobert L Firmin
Life of this patent
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Abstract
Fixed-element, digital-optical measuring devices are disclosed, as are methods for using these devices. The measuring devices have two separate optical pathways with fixed elements that produce a stereo image. The optical pathways may include mirrors, prisms, beam splitters, and other such elements, or two digital sensors may be used. Image distance between stereo copies of a point of interest in the stereo image is measured digitally and converted to a physical distance from the measuring device. The conversion may be done with a non-trigonometric function, such as a function created using empirical data. In some cases, the function may be a function-of-functions that provides a calibration for a number of different lens focal lengths.
Claims22
A method of determining the range to or position of an object, comprising:
- acquiring a stereo image of a scene using a fixed-element stereo optical system;
- acquiring a mono-image of the scene;
- identifying a point of interest on the mono-image;
- mapping the point of interest to a point on the stereo image;
- determining an image distance between the point of interest and a stereo copy of the point of interest;
- and
- converting the image distance to a physical distance using a function-of-functions derived from pre-calibration empirical data, the empirical data function establishing a relationship between the image distance and the physical distance for a plurality of different lens focal lengths.
A fixed-element optical measuring device, comprising:
- a first optical pathway including a first fixed optical element;
- a second optical pathway including a second fixed optical element;
- one or more digital sensors adapted to accept light from the first optical pathway and the second optical pathway to form a stereo image;
- a lens system with a plurality of focal lengths arranged in front of the one or more digital sensors;
- and
- a processing unit that converts an image distance between stereo copies of a point of interest in the stereo image to a physical distance to the measuring device using a function-of-functions constructed from pre-calibration empirical data that relates the image distance to the physical distance for each of the plurality of focal lengths.
A method of generating elevational data for a topographical map, comprising:
- acquiring an overhead stereo image of an area using a fixed-element stereo optical system having a plurality of focal lengths;
- acquiring a mono-image of the area using the fixed-element stereo optical system;
- analyzing the mono-image to identify one or more points of interest for ranging;
- and
- for each of the points of interest
- mapping the point of interest to a point on the stereo image;
- determining an image distance between the point of interest and a stereo copy of the point of interest;
- and
- converting the image distance to a physical distance using a function-of-functions derived from pre-calibration empirical data, the empirical data function establishing a relationship between the image distance and the physical distance for a plurality of different lens focal lengths, including a focal length used in said acquiring.
A method for determining the range to or position of an object, comprising:
- automatically identifying one or more points of interest in a digital stereo image acquired using a fixed-element digital-optical measuring device having a plurality of lens focal lengths;
- determining a distance to the one or more points of interest by measuring an image distance between stereo copies in the digital stereo image for each of the one or more points of interest and using a function-of-functions derived from pre-calibration empirical data to find the distance to each of the one or more points of interest, the empirical data function establishing a relationship between the image distance and the physical distance for a plurality of different lens focal lengths, including a lens focal length of the plurality of lens focal lengths that was used to acquire the digital stereo image.
Dependencies are inferred from the claim text.