Temperature measuring device and temperature measuring method

• US 8,340,468 B2
• Filed: 03/25/2008
• Issued: 12/25/2012
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Meiwa E-Tec Co., Ltd., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Meiwa E-Tec Co., Ltd., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Furukawa, Yuichi, Nakamura, Shingo, Okada, Yuji, Kawahara, Fumio
• Primary Examiner(s): BHATNAGAR, ANAND P
• Application Number:
  US12/593,811
• Publication Number:
  US 20100098321A1
• Time in Patent Office: 1,736 Days
• Field of Search: 382/100, 382/103, 382/130, 382141-153, 382/181, 382/190, 382/195, 382/201, 382217-222, 382293-298, 374/1, 374/2, 374/29, 374100-102, 374/112, 73/250.1, 228/127, 250/316.1, 250/330
• US Class Current: 382/294
• CPC Class Codes: G01J 1/0455 having a throughhole enabling the optical element to fulfil an additional optical function, e.g. a mirror or grating having a through-hole for a light collecting or light injecting optical fibre
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/0003 for sensing the radiant heat transfer of samples, e.g. emittance meter
• CPC Class Codes: G01J 5/48 Thermography; Techniques using wholly visual means

Abstract

Feature points (41, 42, 43) in the heat image (10) of a casting die (1) are extracted and a predetermined geometrical conversion processing is performed on the heat image (10) such that the feature points are superimposed on the reference feature points (61, 62, 63) set in a reference heat image (30) picked up previously to generate a corrected heat image (20). A difference image (40) is generated by superimposing the corrected heat image (20) and the reference heat image (30) such that the corrected feature points (51, 52, 53) in the corrected heat image (20) is superimposed on the corresponding reference feature points (61, 62, 63). With such an arrangement, a highly reliable difference image can be generated even when the imaging field of vision slips off among a plurality of heat images.

Claims

1. A temperature measuring device comprising:

a feature point choosing means for choosing a single feature point or multiple feature points from a heat image of a measurement object;

a corrected heat image generating means for generating a corrected heat image by means of performing one or more image-processing to the heat image including rotating, sliding, enlarging and reducing in such a way that the feature point(s) of the heat image is (are) superimposed on a reference feature point(s) of a reference heat image picked up in advance, on the basis of a coordinate(s) of the feature point(s) of the heat image chosen by the feature point choosing means and a coordinate(s) of the reference point(s) of the reference heat image set in advance; and

a difference heat image generating means for generating a difference image as difference between the corrected heat image and the reference heat image, with the corrected heat image generated being superimposed on the reference image in such a way that the feature point(s) of the corrected heat image is (are) superimposed on the reference feature point(s) of the reference heat image,

wherein one or more points of the feature point(s) in the heat image is (are) single pixel or a cluster of pixels of the heat image and displaying the highest or lowest temperature in predetermined area(s) set in the heat image, and

wherein one or more points of the reference feature point(s) in the reference heat image is (are) single pixel or a cluster of pixels of the reference heat image and displaying the highest or lowest temperature in predetermined area(s) set in the reference heat image.

2. The device according to claim 1, further comprising:

an image pick up means for picking up the heat image.

3. The device according to claim 1 or 2,

wherein at least one of the feature point(s) of the heat image is (are) set as a point fixed relatively to the image pick up means when picking up the heat image.

4. The device according to claim 1 or 2,

wherein the measurement object is a casting mold having a particular portion where becomes higher or lower temperature than surroundings, and

wherein the areas set in the heat image and the reference heat image are set as including the particular portion.

5. The device according to claim 1 or 2,

wherein at least one of the feature point(s) of the heat image is (are) set as a point fixed relatively to the image pick up means when picking up the heat image,

wherein the measurement object is a casting mold having a particular portion where becomes higher or lower temperature than surroundings, and

wherein the areas set in the heat image and the reference heat image are set as including the particular portion.

6. A temperature measuring method, comprising:

picking up a heat image of a measurement object;

choosing a single feature point or multiple feature points from the heat image of the measurement object;

generating a corrected heat image by means of performing one or more image-processing to the heat image including rotating, sliding, enlarging and reducing in such a way that the feature point(s) of the heat image is (are) superimposed on reference feature point(s) of a reference heat image picked up in advance, on the basis of a coordinate(s) of the feature point(s) of the heat image and a coordinate(s) of the reference point(s) of the reference heat image set in advance; and

generating a difference image as difference between the corrected heat image and the reference heat image, with the corrected heat image generated being superimposed on the reference image in such a way that the feature point(s) of the corrected heat image is (are) superimposed on the reference feature point(s) of the reference heat image,

wherein one or more points of the feature point(s) in the heat image is (are) a single pixel or a cluster of pixels of the heat image and displaying the highest or lowest temperature in predetermined area(s) set in the heat image, and

wherein one or more points of the reference feature point(s) in the reference heat image is (are) a single pixel or a cluster of pixels of the reference heat image and displaying the highest or lowest temperature in predetermined area(s) set in the reference heat image.

7. The method according to claim 6,

the measurement object is a casting mold.

8. A temperature measuring device comprising:

a feature point choosing part that chooses a single feature point or multiple feature points from a heat image of a measurement object;

a corrected heat image generating part that generates a corrected heat image by performing one or more image-processing to the heat image including rotating, sliding, enlarging and reducing in such a way that the feature point(s) of the heat image is (are) superimposed on a reference feature point(s) of a reference heat image picked up in advance, on the basis of a coordinate(s) of the feature point(s) of the heat image chosen by the feature point choosing part and a coordinate(s) of the reference point(s) of the reference heat image set in advance; and

a difference heat image generating part that generates a difference image as difference between the corrected heat image and the reference heat image, with the corrected heat image generated being superimposed on the reference image in such a way that the feature point(s) of the corrected heat image is (are) superimposed on the reference feature point(s) of the reference heat image,

wherein one or more points of the feature point(s) in the heat image is (are) single pixel or a cluster of pixels of the heat image and displaying the highest or lowest temperature in predetermined area(s) set in the heat image, and

wherein one or more points of the reference feature point(s) in the reference heat image is (are) single pixel or a cluster of pixels of the reference heat image and displaying the highest or lowest temperature in predetermined area(s) set in the reference heat image.