My local copy.
Terence Eden asked if there was a way to obtain temperature data from his thermal camera without using the closed source Windows app..
After some research, the following SDK was located that can read IRG file data: Infrared thermal imaging irg photo analysis SDK
..which turns out to be a nice small windows DLL that is amenable to reversing with Ghidra. Let's go!
sdk_get_irg_param(char* file, IRG_Param* irg_param); which extracts some info from the header:
struct IRG_Param {
uint16_t width;
uint16_t height;
int32_t emiss;
int32_t airTemp;
int32_t distance;
uint8_t humidity; // not extracted
int32_t refTemp;
int32_t atmTrans;
int32_t K0; // not extracted
int32_t B0; // not extracted
int32_t K1; // not extracted
int32_t B1; // not extracted
int32_t pseudoCol;
int32_t tempUnit;
int32_t gainStatus; // not extracted
}sdk_get_irg_data(char* file, int colIndex, unsigned short* tempData, unsigned char* imageData);
which extracts raw temperature values (K x10) to a block of 16 bit values, and pallettized false colour
image to a block of
YUYV
(aka YUY2) pixels, with the false colour pallette by colIndex parameter.
As reversed from the SDK. Everybody loves ASCII art diagrams right?
(all multi-byte values are little-endian - signedness as defined above)
HEADER:
[ID?] [repeating pattern to <ee> .......] [IP addr?]
0000: <b0 0b 80> <00> <c0 a8 00 00> <HH HH> <WW WW> <00> <c0 a8 00
0010: 00> <HH HH> <WW WW> <00> <c0 a8 00 00> <HH HH> <WW WW> <EE EE
0020: EE EE> <RR RR RR RR> <TT TT TT TT> <DD DD DD DD> <a0 0f
0030: 00 00> <XX XX XX XX> <00 00 00 00> <XX XX XX XX> <00 00
0040: 00 00> <00 00 00 00> <CC> <00 00> <UU> <02> <00 00 00 00> <00>
0050: <00> x 16
0060: <00> * 16
0070: <00> x 14 <ac ca>
[EOH?]
c0 a8 00 00 => Offset beyond the 0x80 byte header for the 16-bit measurements
HH => height (pixels)
WW => width (pixels)
EE => emissivity (0->1 x 10000)
RR => reflected temperature (K, x 10000)
TT => air temperature (K, x 10000)
DD => distance (m, x 10000)
XX => atmospheric transmittance (0->1, x 10000)
CC => pseudo colour index
UU => temperature units (lookup?)
c0 a8 00 00 is the offset beyond header where the 16-bit image temperature measurements starts)
IMAGE DATA:
Follows directly after the header, offset 0x80. Each 8 bit value is range-adjusted luminence
(lowest temperature => 0, highest temperature => 255).
TEMPERATURE DATA:
Follows directly after the image data, offset 0x80 + width * height. Each 16 bit value is K x10