91漫画

Seine Meinung zu unserer Anwendung

Sensorspecs
	<10掳 脰ffnungswinkel
	320x240 Aufl枚sung
Quadratsensor vs Zeilensensor
	Quadratsensor besser weil sehr gutes preisleistungsver盲ltniss / hohe st眉ckzahlen
zeilensensor
	nur bei satelliten
	kosten h枚her
	nicht empfehlenswert laut ihm

Flir Sensoren

lepton 
	3.0 
		datenblat interface sensor
			SDI Interface selbst entwickeln	
		Kann keine Temperatur messen, nur Unterschiede anzeigen
	3.5 
		kann kan radiometrische information == absolute temperatur ausgeben
		f眉r uns nicht relevant
		Wird in Coronatimes gerade sehr gebraucht f眉r Messger盲te...
boson
	320 640
	besser f眉r uns geeignet seiner meinung nach
	aber 10X so teuer

Temperaturunterschied ist entscheident

Von oben kuckend ist temepratur bei menschen nicht so hoch
Schr盲g w盲re besser weil da mehr warme fl盲che vom menschen	

Lepton breakout board

V1.0 alte version , kann vlltpaar features nicht, aber hat keine beschwerden geh枚rt, 30$
V2.0 60$

Erkennung mittels sensoren , 3 unterschiedliche stufen

Johnson criteria
	https://www.ecamsecure.com/blog/thermal-cameras/johnsons-criteria-for-thermal-camera-performance/
detektion 
	2 linienpaare aus = 4 pixel			
erkennung 
	6 linienpaare
identifikation / klassifikation 
	12 linienpaare

Defekte pixel

1-2% pixel tot
M眉ssen ber眉cksichtigt werden
=> kann mittels tracking 眉ber zeit / best盲tigung 眉ber zeit gel枚st werden

1. 160×120 spacial res
2. 50 mKelvin temperature res
3. 71/56掳 opening angle
4. not waterproof
5. more info in this paper:
6. 词250鈧�

Flight@300m

Flight@500m

• • Bought at acalbfi.com
• • Bought v1.4 at acalbfi.com

Compared to the Lepton 3.5 it doesnt offer temperatur measurements, but we are not interested in it anyway so we can use the 3.0 version. Lepton 3.5 cannot be shipped in corona times anyway.

• Python Interfacing :
  • Use lepton3-dev branch for lepton3.x support
  • Master got only lepton2.x support
• Live video:
• Paper on the sensor:

*

• Better imho

*

* HT-201 / HT-301 * 320×240 pixel * 32掳 Opening angle *

• 206 x 156 Thermal Sensor
• 36掳 Field of View
• < 9 Hz Frame Rate
• 1,000 ft. Detection Distance (~300m)
• not waterproof!
• 词250鈧�
• lensmaterial Chalcogenide

Flight@300m

Flight@500m

Flight@700m

Needs special material as glas blocks IR. Common materials for LWIR windows include silicon, germanium, and zinc selenide (LWIR absorption in silicon is on the order of 15%/mm, which means NEDT is adversely affected using a silicon window. Bulk absorption in germanium and zinc selenide is negligible, and performance is essentially unchanged provided both surfaces of the window are anti-reflection (AR) coated.)

It should be stated that occasional water, be it fresh or salt, does not damage Germanium lenses if they are rinsed and dried afterwards. Fire fighting cameras regularly get drenched in water and the camera lens protector just needs to be gently cleaned and dried after the shout. from

From FLIR Lepton Datasheet

More Info:

• Materials in general:
• Cheap Zinc Selenide ZnSe Lenses @ ebay:
• Thermal transparnt plastics:
• Cheap PIR thermal transparent windows:

Lepton 3.0 Germanium Lens

Bought here:

* Image

* Transmission of lens

* Without lens

Intensity of hottest point: 210

* With lens

Intensity of hottest point: 124

The lens dampens the intensity of the heat by at least ~40%, whis is roughly in line with the chart above.

It also created a lens center spot effect in the center of the image. We need to see if this might cause problems.

To be tested in real life conditions.

Test different materials for thermal transparancy with Lepton 3.0 @ Pi4

This time i take photos with normalized colors to min and max temperature. Actually a better test would be using absolute value images. Next time鈥�

left to right

1. 鈥渢hick foil鈥� ~ like a paper 2. 鈥渟uperthin foil鈥� 3. transparent ruler ~2mm 4. magnifying glass ~2mm

0. nothing

1.

2.

3.

4.

without

left to right

1. 鈥渟uperthin foil鈥� 2. 鈥渢hick foil鈥� ~ like a paper 3. transparent ruler 2mm thick 4. glas

Its visible, that thin plastics are a option. The actual thinnest one doesnt protect at all, its too thin. But maybe we can find some cheap fitting material, or we use the professional thermal plastics.

• Images of water are more cold at center than edges
  • Due to vignetting

• Flat field calibration
  • Build avg frame over multiple frames and save flat_field_calib
  • frame_corrected = frame_raw - flat_field_calib
  • Implementation

Camera

Flight example

85鈧�

Grabber card