Visual template-based thermal inspection system

• US 8,374,438 B1
• Filed: 02/10/2012
• Issued: 02/12/2013
• Est. Priority Date: 10/04/2007
• Status: Active Grant

• Current Assignee: RedShift BioAnalytics, Inc.
• Original Assignee: Redshift Systems Corporation
• Inventors: Wagner, Matthias
• Primary Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US13/370,558
• Time in Patent Office: 368 Days
• Field of Search: 382/209, 382/100, 382/115, 382/118, 382/128, 382/117, 382/103, 382/106, 250/332, 250/334, 250/342, 250/330, 250/338.1, 348/164, 348/E5.09, 348/E3.01, 348/166, 348/E5.081, 348/263, 348/239, 348/167, 348/168, 340/522, 340/587, 340/632, 340/577, 340/628, 374/124, 374/100, 374/120, 374/E13.001, 374/E13.002, 374/E13.003, 374/121, 374/130, 430/201, 430/964, 430/944, 430/339, 430/522, 430/517, 430/203, 430/351, 430/559, 430/617, 430/955, 430/200, 430/510, 359/362, 359/399, 359/421, 359/350
• US Class Current: 382/209
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

An imaging device and system include integration of an imaging camera (visible-light or near-infrared) with a thermal infrared sensor, capturing a baseline image from this camera simultaneously with acquisition of baseline thermal infrared data, which may correspond to a known good condition or part, automatic generation of an edge version of the baseline image for use as an alignment template, and on subsequent thermal infrared inspections, superposition of the alignment template on a live video image from the visible camera, so as to facilitate highly repeatable alignment of the thermal infrared sensor to an object being inspected.

Claims

1. An imaging device, comprising:

a first sensor operative to receive first sensor input in an infrared wavelength band from a first sensor imaging field and to generate a corresponding first sensor output signal;

a second sensor operative to receive second sensor input in a second wavelength band from a second sensor imaging field and to generate a corresponding second sensor output signal, the second sensor imaging field containing or being larger in extent than the first sensor imaging field, the first and second imaging fields being of known spatial registration with respect to each other;

a laser operative to emit radiation within the second wavelength band and illuminating a reflective object within the second sensor imaging field to generate reflective radiation, the reflected radiation being received by the second sensor, the laser position and direction of propagation of the laser radiation being of known spatial registration with respect to the second sensor; and

an image processor operative to;

(1) receive the first and second sensor output signals,

(2) extract from the second sensor output the position of the illuminated area within the second sensor imaging field,

(3) calculate from the position and known registration of the laser and second sensor the distance to the reflective object,

(4) calculate from the distance and the spatial registration of the first and second sensor a registration offset,

(5) using the registration offset to register the first and second imaging fields.

2. The imaging device of claim 1 wherein the first sensor is an infrared point thermometer.

3. The imaging device of claim 1 wherein the first sensor is a two-dimensional thermal sensor.

4. The imaging device of claim 1 wherein the second sensor output is comprised of a time succession of image frames for display.

5. The imaging device of claim 4 wherein the laser illumination is modulated.

6. The imaging device of claim 5 wherein the display of the reflective object within the second sensor imaging field is generated using frames wherein the laser is modulated to be turned off.

7. The imaging device of claim 4 wherein the image frames are processed to enhance detection of the laser illumination.

8. The imaging device of claim 1 wherein the laser is outside the human visible wavelength range.

9. The imaging device of claim 1 wherein the laser illumination consists of multiple points of illumination within the second sensor imaging field.

10. The imaging device of claim 9 wherein the multiple points are in a grid pattern.

11. The imaging device of claim 9 wherein the spatial registration offset varies across the second sensor imaging field.

12. The imaging device of claim 9 wherein the spatial registration offset is used to predict the location of changes in depth within the second sensor imaging field.

13. The imaging device of claim 9 wherein the spatial registration offset is used to predict the location of changes in depth within the first sensor imaging field.

14. The imaging device of claim 9 wherein the signal processor performs an alignment process of a succession of image frames.