Modular digital audio system having individualized functional modules

• US 5,991,437 A
• Filed: 07/12/1996
• Issued: 11/23/1999
• Est. Priority Date: 07/12/1996
• Status: Expired due to Term

• Current Assignee: Sizmek Technologies Inc (Sizmek, Inc.)
• Original Assignee: Real-Time Geometry Corporation
• Inventors: Zhilyaev, Alexander, Petrov, Michael, Lebedev, Alexei, Migdal, Alexander
• Primary Examiner(s): Kelley, Christopher S.
• Application Number:
  US08/678,804
• Time in Patent Office: 1,229 Days
• Field of Search: 382/106, 382/154, 382/285, 348/42, 348/47, 348/48, 348/49, 348/50, 348/139, 356/3
• US Class Current: 382/154
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence
• CPC Class Codes: G01B 11/2504 Calibration devices

Abstract

A system for high accuracy calibration of a scanning system, which provides an object for calibration of a known geometry, such as a plane or a sphere. Upon that object is marked a pattern of points or geometric shapes, such as a set of equilateral triangles or their vertices. A set of computer programmed elements process photographic images of the object (containing a depiction of the pattern of geometric objects) and scanned images of the object to calibrate to high precision parameters, including a focal point relationship value for scanning systems which use a camera as an image collector (which describes the relationships between the focal point of the lens and the light/image collection device of the camera), a set of values to correct for distortion of the lens, the relative distance between the image collector and the scanner light source and also an initial angle to determine light position scanning. The known geometric constraints of the object allow the location of the object to be determined by photographic images. By scanning the object and computing 3D X,Y,Z coordinates for those points against a constraint that the X,Y,Z coordinates fit onto the surface of the object, the system calibrates parameters pertaining to the relative distances between the image collector and light source, an initial angle of rotation for systems which employ movable light sources and other parameters. The system is applied to multiple camera scanning systems to calibrate rotation matrices and translation vectors which facilitate the joining of the scanned data. The system further facilitates the design of flexible and movable scanning systems, such as portable scanners.

Claims

1. A system for determining the location of a light source relative to a image collector, the image collector comprising a lens with a focal point and a light collection device at a focal distance away from the lens which creates images based on the light which passes through the lens, the image collector comprised to capture images of objects and output information concerning the image, the light source placed at a location apart from the image collector and comprised to direct a beam of light on an object, the light beam comprised to reflect from the object the image collector comprised capture images of the object both when the light source projects the beam and when no beam is projected, the system comprising:

(a) a calibration object of a predetermined geometric form placed in a position for scanning, the calibration object being marked with a pre-selected geometric shape of known form, the geometric shape having a plurality of vertices of which the relative locations between vertices is also known;

(b) a computer comprising a processor coupled to a memory and adapted to accept information concerning an image of the calibration object output by the camera;

(c) the computer further adapted to process the information concerning the image of the calibration object and locate the two dimensional points within the image that describe the vertices the geometric shape;

(d) the computer being further adapted to calibrate the location of the calibration object by determining a three dimensional point value for each vertex according to a constraint by which the three dimensional point values must lie on the calibration object and maintain the relative known relationship to each other;

(e) the light source adapted to direct light beams to different positions about the object, and the image collector collecting images of the light beams as they reflect from the object;

(f) the computer further adapted to accept as input information concerning the images containing reflections of the light beams;

(g) the computer further adapted to locate within the two dimensional images a two dimensional coordinate for the reflected image of the light beam as it reflects from the calibration object;

(h) the computer further adapted to determine the location of the light source relative to the image collector by triangulating according to the determined focal distance a three dimensional coordinate from each two dimensional coordinate according to the constraint that the all the coordinates must lie on the calibration object at its location.

2. A system for calibrating the initial settings in a scanning system which collects three dimensional data about an object by triangulation, the scanning system comprising a light source which positions a beam of light on an object, the beam of light being comprised to reflect from the object, an image collector being located at a position relative to the light source and comprising a lens system and a two dimensional light collection device and configured to capture and output a set of signals comprising a two dimensional image both when no beam of light has been projected and when the light source positions a beam reflects from the object for capture in the image, and a computer coupled to the light source and image collector and comprised of a processor, memory and programmed elements to control the placement of beams of light on the object and accept the output of images from the camera, the system for calibration comprising:

(a) a calibration object of a predetermined geometric form placed in a position for scanning, the calibration object being marked with a pre-selected geometric shape of known form, the geometric shape having a plurality of vertices of which the relative locations between vertices is also known;

(b) a computer comprising a processor coupled to a memory and comprised accept information concerning an image of the calibration object output by the camera;

(c) the computer further adapted to process the information concerning the image of the calibration object and locate the two dimensional points within the image that describe the vertices the geometric shape;

(d) the computer being further adapted to calibrate the focal distance and the location of the calibration object by determining a three dimensional point value for each vertex according to a constraint by which the three dimensional point values must lie on the calibration object and maintain the relative known relationship to each other;

(e) the light source adapted to direct light beams to different positions about the object, and the image collector being comprised to collect images of the light beams as the reflect from the object;

(f) the computer further adapted to accept as input information concerning the images containing reflections of the light beams;

(g) the computer further adapted to locate within the two dimensional images a two dimensional coordinate for the reflected image of the light beam as it reflects from the calibration object; and

(h) the computer further adapted to determine the location of the light source relative to the image collector by triangulating according to the determined focal distance a three dimensional coordinate from each two dimensional coordinate according to the constraint that the all the coordinates must lie on the calibration object at its location.

3. A method for determining the location of a light source relative to a image collector, the image collector comprising a lens with a focal point and a light collection device at a focal distance away from the lens which creates images based on the light which passes through the lens, the image collector comprised to capture images of objects and output information concerning the image, the light source placed at a location apart from the image collector and comprised to direct a beam of light on an object, the light beam comprised to reflect from the object the image collector comprised capture images of the object both when the light source projects the beam and when no beam is projected, the method comprising the steps of:

(a) placing a calibration object of a predetermined geometric form in a position for scanning, the calibration object being marked with a pre-selected geometric shape of known form, the geometric shape having a plurality of vertices of which the relative locations between vertices is also known;

(b) outputting an image of the object by the camera and accepting the image in a computer comprising a processor coupled to a memory and adapted to accept information concerning an image of the calibration object output by the camera;

(c) processing with the computer the image of the calibration object to locate the two dimensional points within the image that describe the vertices the geometric shape;

(d) calibrating the focal distance and the location of the calibration object with the computer by determining a three dimensional point value for each vertex according to a constraint by which the three dimensional point values must lie on the calibration object and maintain the relative known relationship to each other;

(e) directing light beams from the light source to different positions about the object, and collecting in the image collector images of the light beams as they reflect from the object;

(f) accepting information concerning the images containing reflections of the light beams in the computer;

(g) locating with the computer within the two dimensional images a two dimensional coordinate for the reflected image of the light beam as it reflects from the calibration object;

(h) determining with the computer the location of the light source relative to the image collector by triangulating according to the determined focal distance a three dimensional coordinate from each two dimensional coordinate according to the constraint that the all the coordinates must lie on the calibration object at its location.

4. A method for calibrating the initial settings in a scanning system which collects three dimensional data about an object by triangulation, the scanning system comprising a light source which positions a beam of light on an object, the beam of light being comprised to reflect from the object, an image collector being located at a position relative to the light source and comprising a lens system and a two dimensional light collection device and configured to capture and output a set of signals comprising a two dimensional image both when no beam of light has been projected and when the light source positions a beam reflects from the object for capture in the image, and a computer coupled to the light source and image collector and comprised of a processor, memory and programmed elements to control the placement of beams of light on the object and accept the output of images from the camera, the method for calibration comprising the steps of:

(a) placing a calibration object of a predetermined geometric form in a position for scanning, the calibration object being marked with a pre-selected geometric shape of known form, the geometric shape having a plurality of vertices of which the relative locations between vertices is also known;

(b) accepting information concerning an image of the object with a computer comprising a processor coupled to a memory and comprised accept information concerning an image of the calibration object output by the camera;

(c) processing with the computer the information concerning the image of the calibration object to locate the two dimensional points within the image that describe the vertices the geometric shape;

(d) calibrating the focal distance and the location of the calibration object with computer processing by determining a three dimensional point value for each vertex according to a constraint by which the three dimensional point values must lie on the calibration object and maintain the relative known relationship to each other;

(e) directing with the light source light beams to different positions about the object, and the image collector being comprised to collect images of the light beams as the reflect from the object;

(f) accepting information concerning the images with the computer further adapted to accept as input information concerning the images containing reflections of the light beams;

(g) locating within the two dimensional images a two dimensional coordinate for the reflected image of the light beam as it reflects from the calibration object; and

(h) determining with the computer the location of the light source relative to the image collector by triangulating according to the determined focal distance a three dimensional coordinate from each two dimensional coordinate according to the constraint that the all the coordinates must lie on the calibration object at its location.