16-bit TLinear data fluctuation issue

Hi all,
I’m currently conducting a face temperature measurement experiment with FLIR Lepton 3.5 Cam on Purethermal 2. I got an issue when trying to extract the temperature value of my face, the temperature values of every pixel increases ~1 degC and fall back slowly after.

Experiment setup description:
4-minute cycle:br
1 minute idle (fake face, wrong temperature) + FFC performancebr (at sample 540)
1 more minute idlebr
1 minute showing real face (human temperature): samples 1100-1700br
idles till end

– The camera produced strange data when I came into the capturing scene (at around 1100th sample), every read-in values (hottest temp. – cyan, hot reference black body temp. – red pointed line, cool reference temp. – blue pointed line, and forehead temp. – black dotted line) increases approx. 1 degC and slowly fall back after a period of ~200 samples.br

– I wonder what causes the whole frame’s data to rise up like that, and if there’s any method to avoid that effect?FYI, I use TLinear mode to extract raw 16-bit data, below are my detailed settings:

LEP_GetAgcCalcEnableState LEP_AGC_DISABLEbr
LEP_GetRadEnableState LEP_RAD_ENABLEbr
LEP_GetRadTShutterMode LEP_RAD_TS_FIXED_MODEbr
LEP_GetRadTLinearEnableState LEP_RAD_ENABLEbr
LEP_GetRadTLinearAutoResolution LEP_RAD_DISABLEbr
Radiometric spotmeterRoi 59 79 60 80br
LEP_GetOemVideoOutputEnable LEP_VIDEO_OUTPUT_DISABLEbr
LEP_GetVidSbNucEnableState LEP_VID_SBNUC_DISABLEbr
LEP_GetSysGainMode LEP_SYS_GAIN_MODE_HIGHbr
LEP_GetSysTelemetryEnableState 0

Thank you for helping.
Best regards,
Hung

• This topic was modified 1 year, 10 months ago by  Hung.
• This topic was modified 1 year, 10 months ago by  Hung.
• This topic was modified 1 year, 10 months ago by  Hung.