SOLVED - Flir Boson "Error during lens calibration" issue - Page 1
Forum section: electronics / general

author: hap2001
author_rank: Regular Contributor
timestamp: July 20, 2024, 02:10:22 pm
content: Hello.As the screenshot shows, every time I try to do lens calibration, it always give up after reading hot and cold shots, without detailed error message. What is causing this?It works normally otherwise.I'm not calibrating with a proper black body, I'm just point it to some surface just hot-to-touch, maybe 45-50C. Is it because the surface is not hot enough? But I don't want to pay for a black body just to find out the error still exist.Any ideas?

author: IR_Geek
author_rank: Regular Contributor
timestamp: July 20, 2024, 03:08:55 pm
content: is it also doing it when you look at a room temperature blackbody? Just to confirm, the internal shutter is not active and you are looking at an external surface?

author: hap2001
author_rank: Regular Contributor
timestamp: July 20, 2024, 03:22:32 pm
content: Quote from: IR_Geek on July 20, 2024, 03:08:55 pmSorry I don't really get your question...The shutter is automatically kept open during calibration.It requires 2 scene, one cold(room temp), one hot, I gave it both.

author: IR_Geek
author_rank: Regular Contributor
timestamp: July 20, 2024, 06:01:27 pm
content: Sorry for the confusion. You are performing a two point (i.e hot and cold) external (i.e. in front of the optic) NUC.In that case, what are your count value difference between the hot blackbody and cold blackbody? Not the temperature difference but count values. If those values are not enough then the software can fail to create a linear slope. If one of those values are saturated then it could also lead to a failed NUC.count value = digital number = raw value .... If possible select a region and look at the histogram distribution of the count values. You should see a nice distribution. Extreme outliers due to bad pixels could also be an issue.

author: DaJMasta
author_rank: Super Contributor
timestamp: July 20, 2024, 06:21:09 pm
content: You're following this basic procedure (about 2 minutes in)?https://www.flir.com/oem/thermal-integration-made-easy/3rd-party-lens-calibration-with-boson--boson/My guess - your surface is not uniform enough to look like a real thermal blackbody (or maybe the surface emissivities of your two targets are pretty different?) so the calibration is requiring compensation outside of some preset maximum threshold and it's failing. The target surfaces must be the same emissivity and as uniform as possible as you're trying to calibrate out nonuniformity in the image because of the lens construction.

author: hap2001
author_rank: Regular Contributor
timestamp: July 21, 2024, 12:20:16 pm
content: Thank you guys.Yes I'm performing a two point lens calibration, as shown in the video.I will try some other surfaces later, and will report back.

author: Fraser
author_rank: Super Contributor
timestamp: July 21, 2024, 01:23:02 pm
content: Please consider buying a Blackbody if you want reliable results. You can use an ambient temperature painted piece of metal as one reference point and the Blackbody as the other, higher temperature reference point. Or buy two black bodies ! They are very useful bits of kit and you can sometimes find a bargain on eBay. Just look at these Blackbodies used with COVID screening cameras…. An absolute steal at $25https://www.ebay.com/itm/266703545467?You get a nice quality thermally flat emission plate of decent size plus the ability to set a temperature between Ambient+5C and +60C. If the range is unlocked on the PID controller (easy to do from PID user manual) you can go up to around +80C with ease. Higher may be possible but it is pushing the limits of the heater power and insulation used in the unit. Go on spoil yourself with one of these Blackbodies. You will not regret it.

author: hap2001
author_rank: Regular Contributor
timestamp: July 21, 2024, 04:53:53 pm
content: Thank you.Interestingly, lens calibration on Tau would never give error, I tried pointing it at anything (such as my face) as "blackbody", and it would just finish the process, but with weird image afterwards, of course.

author: hap2001
author_rank: Regular Contributor
timestamp: July 22, 2024, 10:26:13 am
content: I solved the problem by cheating:Since I have 2 Bosons of exact same model and lens, I copyed the one with good calibration data to the one without, then did SFFC calibration, which only need 1 ambient surface, now it works well.I'm providing the lens calibration data here, so anyone with the same model can use.

author: IR_Geek
author_rank: Regular Contributor
timestamp: July 22, 2024, 02:06:56 pm
content: Good work! Have you tried to perform a 2 point external after you uploaded the new file? Wondering if there was some corruption in the original NUC file that was causing issues.

author: hap2001
author_rank: Regular Contributor
timestamp: July 23, 2024, 12:48:37 pm
content: Quote from: IR_Geek on July 22, 2024, 02:06:56 pmI just tried and it's exactly same error, guess it need a proper black body to be done.