Scanning system with stereo camera set

• US 7,639,372 B2
• Filed: 03/08/2004
• Issued: 12/29/2009
• Est. Priority Date: 03/07/2003
• Status: Active Grant

• Current Assignee: Dimensional Technology International, Inc.
• Original Assignee: Dimensional Technology International, Inc.
• Inventors: Gerlach, Dieter, Kellner, Helmut
• Primary Examiner(s): Toatley, Jr.; Gregory J
• Assistant Examiner(s): Slomski; Rebecca C
• Application Number:
  US10/548,055
• Publication Number:
  US 20060182308A1
• Time in Patent Office: 2,122 Days
• Field of Search: None
• US Class Current: 356/610
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06T 7/593 from stereo images

Abstract

A scanning system includes one or more stereo camera sets (10) for detecting qualitative and quantitative anomalies of an object (40). Each stereo camera set (10) includes two cameras (12, 14) and a projector (16). Each camera (12, 14) is calibrated to correct any distortion due to misalignment of the CCD matrix array (18) and deficiencies of the optical system. The projector (16) projects an absolute encoded pattern (32, 34, 36) onto the object (40) to be measured and is capable of varying the intensity of the emitted electromagnetic energy in the infrared, visible and ultraviolet spectrums. A plurality of camera sets (10) can be combined in a scanning system matrix (42, 44) capable of detecting anomalies of the object (40) in a three-dimensional room (26). The three-dimensional room (26) can be of any desirable size, depending on the number of stereo camera sets (10). The data from the cameras (12, 14) is pre-processed by gate arrays (62) before being transmitted via digital signal processors (66) to a computer interface (64) for display of the measurement. As a result, the amount of data transferred is streamlined, thereby reducing operating time and enabling the scanning system to very accurately detect anomalies of the object (40) in a very short period of time.

Claims

1. A scanning system for detecting an anomaly on a surface of an object (40) when the object is placed within a three-dimensional room (26), the system comprising:

a calibrated stereo camera set (10) including a pair of cameras (12, 14), each camera (12, 14) being calibrated for distortion following a calibration process comprising measuring a position of each dot (20) of a dot matrix reference system (18) within a field of view (22) of each camera (12, 14), and calibrating the stereo camera set (10) by moving the dot matrix reference system (18) in two-dimensions while the stereo camera set (10) is located at a plurality of selected elevations, thereby defining the three-dimensional room (26); and

a projector (16) having a medium with absolute encoded pattern (32) thereon, and a light source (38) for projecting the absolute encoded pattern (32) on the surface of the object (40).

2. The scanning system according to claim 1, further comprising a plurality of camera sets (10) arranged in a scanning matrix (42, 44) for scanning the surface of the object (40) in the three-dimensional room (26).

3. The scanning system according to claim 1, wherein the light source (38) of said projector (16) is capable of emitting electromagnetic energy at three different frequencies onto a surface of the object (40), the light source (38) capable of varying an intensity of each of the three frequencies of electromagnetic energy.

4. The scanning system according to claim 3, wherein a frequency of the light source is selected based on an optical characteristic of the surface of said object (40).

5. The scanning system according to claim 3, wherein the projector (16) emits the absolute encoded pattern (42, 44) in both a first direction and a second direction.

6. The scanning system according to claim 3, wherein the electromagnetic energy is in the form of visible light.

7. The scanning system according to claim 3, wherein the frequency and intensity of said electromagnetic energy varies as a function of time.

8. The scanning system according to claim 1, wherein the absolute encoded pattern (32) comprises a stripe pattern (34).

9. The scanning system according to claim 1, wherein the absolute encoded pattern (32) comprises a pattern (34) of round dots.

10. The scanning system according to claim 1, wherein the object (40) is recognized by the stereo camera set (10) by using a hierarchical arrangement (60) in which a gate array (62) determines which data from an array of data is necessary for recognition of the object (40), and which data is necessary for computer interface operation.

11. the scanning system according to claim 1, wherein the light source (38) varies and intensity of the electromagnetic energy emitted from the light source (38).

12. the scanning system according to claim 1, wherein a spectrum of electromagnetic energy emitted from the object (40) depends on a surface characteristic of the object (40).