# Lepton 3.5, Help with "Get object temp"

**URL:** https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121
**Category:** OpenMV Boards
**Created:** [March 23, 2023, 6:14pm UTC](https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121 "2023-03-23T18:14:00Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![Mohawkdata](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Mohawkdata](https://forums.openmv.io/u/Mohawkdata)
#### Post date: [March 23, 2023, 6:14pm UTC](https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121/1 "2023-03-23T18:14:00Z")

</div>

Hello, The Flir Lepton 3.5 works really well, but I’m having a hard time understanding the relationship between the Threshold values and the min & max temperature.

I would like to read/measure temperatures around 180C. It would be nice to know a litter more about the relationship between the two so I can get the temperatures above 35C.

Thank you for your help, sorry if I missed something.

# Color Tracking Thresholds (Grayscale Min, Grayscale Max)

threshold\_list = [(200, 255)]

# Set the target temp range here

min\_temp\_in\_celsius = 20.0  
max\_temp\_in\_celsius = 35.0

---

<div class="post-metadata">

### Author: ![kwagyeman](https://yyz1.discourse-cdn.com/flex029/user_avatar/forums.openmv.io/kwagyeman/32/4_2.png) [@kwagyeman](https://forums.openmv.io/u/kwagyeman)
#### Post date: [March 23, 2023, 6:30pm UTC](https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121/2 "2023-03-23T18:30:43Z")

</div>

It’s simply:

(max\_temp\_in\_celsius - min\_temp\_in\_celsius) / 255

Each pixel value… 0-255 is then mapped to the range you said. In your case above 1 LSB is worth ~0.05C (0.05882352941176470588235294117647)

The image processing library doesn’t understand temp. So, it’s looking at the pixel values. Which in this case are 200\*~0.05C + 20C ~= 31.7C and 255\*~0.05C + 20C ~= 35C

---

<div class="post-metadata">

### Author: ![Mohawkdata](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Mohawkdata](https://forums.openmv.io/u/Mohawkdata)
#### Post date: [March 23, 2023, 7:29pm UTC](https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121/3 "2023-03-23T19:29:16Z")

</div>

Thank you for the quick response!!

---

<div class="post-metadata">

### Author: ![oramafanis](https://yyz1.discourse-cdn.com/flex029/user_avatar/forums.openmv.io/oramafanis/32/1783_2.png) [@oramafanis](https://forums.openmv.io/u/oramafanis)
#### Post date: [March 24, 2023, 7:46am UTC](https://forums.openmv.io/t/lepton-3-5-help-with-get-object-temp/8121/4 "2023-03-24T07:46:44Z")

</div>

please also see that:

- Scene Dynamic Range - _High Gain Mode:_ -10° to +140°C; _Low Gain Mode:_ -10° to +400°C (at room temperature), -10° to +450°C (typical)  
so you have to deal with low gain mode for this temps i think…