FLIR 红外照相数据thermal image温度计算方法

Tags: /硬件开发/   Date Created:

可以用exiftool从FLIR 红外照片中提取RAW数据，其裸数据是以JPEG段保存在JPEG文件中的，可以用MagicEXIF 元数据编辑器查看到各个APP段的数据。

FLIR照片数据，包括几个部分： EXIF和图像数据，EXIF包括常规的相机信息，GPS定位等信息，还有XMP数据，包含了一些FLIR的基础信息。

然后是JPEG的APP段数据（RAW数据）

用exiftool -a -flir:all 111.jpg可以导出部分FLIR的参数，如下面的Planck参数等。

exiftool -b 可以导出裸数据。

Variant A: Emissivity of object = 1,0

boundary condition:
     object distance = 0 
     external optics transmission = 1.0

T = B / ln(R1/(R2*(S+O))+F)

T = object temperature in Kelvins
S = 16 Bit RAW value
R1 Planck R1 constant
R2     Planck R2 constant
B    Planck B constant. Value range 1300 - 1600.
F     Planck F constant. Value range 0.5 - 2.
O    Planck O (offset) constant. Its a negative value.

ln() natural logarithm

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Variant B: Emissivity of object < 1,0

boundary condition:
    object distance = 0 
    external optics transmission = 1.0

now me must calculate the amount of radiance from reflected objects
for that, we need two auxiliary calculation

RAW_refl=R1/(R2*(e^(B/T_refl)-F))-O
 T_refl = reflected temperature in Kelvins
 RAW_refl is linear to amount of radiance of the reflected objects
 e  Euler's number

RAW_obj=(S-(1-Emissivity)*RAW_refl)/Emissivity
 RAW_obj is linear to amount of radiance of the measured object
  Emissivity = Emissivity of object
  S = 16 Bit FLIR RAW value

now we use the formula from variant A and replace the 16-Bit-Image-Value "S" with the calculated RAW_obj
T_obj= B / ln(R1/(R2*(RAW_obj+O))+F)
  T_obj = object temperature in Kelvins
  R1 Planck R1 constant
  R2     Planck R2 constant
  B    Planck B constant. Value range 1300 - 1600.
  F     Planck F constant. Value range 0.5 - 2.
  O    Planck O (offset) constant. Its a negative value.