Method and system of two-point correction based on temperature substitution

Patent metadata

Field	Value
Publication number	US-11828655-B2
Application number	US-202117345331-A
Country	US
Kind code	B2
Filing date	Jun 11, 2021
Priority date	Dec 16, 2020
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A method and system of two-point correction based on temperature substitution, includes: a black body related to the lens temperature is arranged outside a lens, a first black body arranged in front of the lens of an infrared thermal camera, so as to collect a gray value of the first black body; a temperature of the first black body being equal to the lens temperature; a second black body arranged in front of the lens of the infrared thermal camera, so as to collect a gray value of the second black body; a temperature of the second black body being higher than the lens temperature. Two correction parameters obtained by black body calculation related to temperature are strongly applicable, which eliminates the problem of image quality deterioration caused by temperature changes and greatly eliminates the pot lid phenomenon due to non-uniformity, thereby accurately calculating the corrected gray value.

First claim

What is claimed is:

1. A method of two-point correction based on temperature substitution, comprising:
acquiring a lens temperature of an infrared thermal camera in the thermal equilibrium state;
acquiring a gray value of a first black body arranged in front of a lens of the infrared thermal camera; a temperature of the first black body being equal to a temperature of the lens;
acquiring a gray value of a baffle; the baffle being arranged between the lens of the infrared thermal camera and a detector of the infrared thermal camera;
correcting the gray value of the first black body according to a first two-point correction parameter to obtain a corrected first uniform gray value;
correcting the gray value of the baffle according to the first two-point correction parameter to obtain a corrected second uniform gray value;
acquiring a first correction parameter according to the gray value of the first black body;
the first uniform gray value; the gray value of the baffle and the second uniform gray value;
acquiring a gray value of a second black body arranged in front of the lens of the infrared thermal camera; the second black body having a temperature that is higher than the lens temperature by a pre-set temperature value;
correcting the gray value of the second black body according to a second two-point correction parameter to obtain a corrected third uniform gray value;
acquiring a second correction parameter according to the gray value of the first black body;
the first uniform gray value; the gray value of the second black body; and the third uniform gray value; and
correcting a gray value to be corrected according to the first correction parameter;
the second correction parameter; the first uniform gray value and the second uniform gray value to obtain a corrected gray value.

2. The method of two-point correction based on temperature substitution according to claim 1 ; further comprising; before obtaining the lens temperature of the infrared thermal camera in the thermal equilibrium state:
heating the core of the infrared thermal camera for a pre-set time period; to cause the infrared thermal camera to achieve a thermal equilibrium state.

3. The method of two-point correction based on temperature substitution according to claim 1 ; wherein the gray value of the first black body is corrected according to the first two-point correction parameter to obtain the corrected first uniform gray value; and the gray value of the baffle is corrected to obtain the corrected second uniform gray value;
which is specifically expressed as:

{

Y

X
⁢
1

=

a
1

·

X
1

+

b
1

Y
B

=

a
1

·
B

+

b
1

wherein; X 1 is the gray value of the first black body; B is the gray value of the baffle; Y X1 is the first uniform gray value; Y B is the second uniform gray value; a 1 is the first correction parameter;
and b 1 is the first correction parameter quantity.

4. The method of two-point correction based on temperature substitution according to claim 1 ; wherein the first correction parameter is acquired according to the gray value of the first black body; the first uniform gray value; the gray value of the baffle and the second uniform gray value; which is specifically expressed as:
a 1 =( Y B −Y X1 )/( B−X 1 )
wherein; a 1 is the first correction parameter; X 1 is the gray value of the first black body; B is the gray value of the baffle; Y X1 is the first uniform gray value; Y B is the second uniform gray value.

5. The method of two-point correction based on temperature substitution according to claim 1 ; wherein the gray value of the second black body is corrected according to the second two-point correction parameter to obtain the corrected third uniform gray value;
which is specifically expressed as:
Y X2 =a 2 ·X 2 +b 2

wherein; a 2 is the second correction parameter; X 2 is the gray value of the second black body; Y X2 is the third uniform gray value; and b 2 is the second correction parameter quantity.

6. The method of two-point correction based on temperature substitution according to claim 1 ; wherein the second correction parameter is acquired according to the gray value of the first black body; the first uniform gray value; the gray value of the second black body; and the third uniform gray value; which is specifically expressed as:
a 1 =( Y B −Y X1 )/( B−X 1 )
wherein a 2 the second correction parameter; X 1 is the first uniform gray value;
X 1 is the gray value of the first black body; X 2 is the gray value of the second black body; and Y X2 is the third uniform gray value.

7. The method of two-point correction based on temperature substitution according to claim 1 ; wherein the gray value to be corrected is corrected according to the first correction parameter; the second correction parameter; the first uniform gray value and the second uniform gray value to obtain the corrected gray value; which is specifically expressed as:
Y X2 =a 2 ·X 2 +b 2
wherein, X 1 is a difference value between the corrected second uniform gray value and the corrected first uniform gray value, Y X1 is the corrected first uniform gray value, Y B is the corrected second uniform gray value, ads the first correction parameter, a 2 is the second correction parameter, B is the gray value of the baffle, X is the gray value to be corrected, and Y is the corrected gray value.

8. The method of two-point correction based on temperature substitution according to claim 7 ; wherein a calculation method of the difference value comprises:
obtaining a current lens temperature and a current baffle temperature; and
calculating a difference value according to Y B −Y X1 =F(T J −T B ) a formula by using a pre-stored fitting function; wherein TJ is the current lens temperature; TB is the current baffle temperature;
and F is the fitting function;
wherein the fitting function is determined by:
during the process

Assignees

• Univ Electronic Sci & Tech China

Inventors

• Zhou Yun
• Lv Jian
• Que longcheng
• He Kang
• Mi Guanyu

Classifications

• G01J5/00 Primary

  Radiation pyrometry, e.g. infrared or optical thermometry · CPC title

• G06T7/0002

  Inspection of images, e.g. flaw detection · CPC title

• G06T7/80

  Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration · CPC title

• G06T7/90

  Determination of colour characteristics · CPC title

• G01J5/80

  Calibration (using comparison with reference sources G01J5/52) · CPC title