Bleazdale
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Joined: Mon May 17, 2021 2:21 pm

Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Mon May 17, 2021 2:27 pm

Hello,

I am a PhD researcher at Lancaster University and I am using the Pi HQ camera and an infrared sensitive sensor for observing plants. I can't find information online about the spectral range the IMX 477 sensor has once the IR-Cut filter is removed (I can only find the transmissivity of the IR cut filter and the relative response for the visible range). Does anybody have any information about the spectral range the sensor can detect, or a graph of the relative response of the sensor?

Thank you very much,

Al

Jack Hogan
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Contact: Website

Re: Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Tue May 18, 2021 10:52 am

I have only seen filterless spectral sensitivity curves that stop at 700nm for the IMX477, for instance in the data sheet here.

I would be interested in taking a look at the curves with IR filter that you have found.

Jack

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Gavinmc42
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Joined: Wed Aug 28, 2013 3:31 am

Re: Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Tue May 18, 2021 11:35 am

Arducam are saying they have some Starvis sensors coming.

There is already some that work.
viewtopic.php?f=43&t=306974&p=1836434&h ... s#p1836434

The Astrophotography guys have data on the IMX462, it uses a dye based Bayer pattern that is mostly transparent in IR.
I have seen a datasheet on the 462 somewhere.

I have used Hyper-spectral USB3 cameras even on old Pi3's.
https://www.ximea.com/en/products/hyper ... -sm5x5-nir
Much more expensive ;)
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

cpixip
Posts: 49
Joined: Mon May 01, 2017 7:56 am

Re: Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Tue May 18, 2021 1:28 pm

you might want to have a look at the following git-repository:

https://github.com/bluegreen-labs/raspb ... _responses

and especially the following .png

https://github.com/bluegreen-labs/raspb ... arCMOS.png

Basic idea: in the near IR, the filters of the Bayer array are not acting at all as wavelength-specific filters. All CMOS imagers are therefore sort of created equal, just showing the basic CMOS-IR sensitivity. In any case, there is no sensitivity left above 1000 nm.

Jack Hogan
Posts: 113
Joined: Wed May 13, 2020 2:08 pm
Contact: Website

Re: Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Tue May 18, 2021 2:29 pm

cpixip wrote:
Tue May 18, 2021 1:28 pm
In any case, there is no sensitivity left above 1000 nm.
Silicon is transparent to photon energies less than 1.14eV (i.e. wavelengths above 1086.8nm), because more energy than that is needed for the photoelectron effect to take place.

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Gavinmc42
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Re: Spectral Sensitivity of the Pi HQ Camera / IMX 477 Sensor

Wed May 19, 2021 12:00 am

Deeper photon wells to capture more IR
https://www.qhyccd.com/index.php?m=cont ... d=61&cut=3

Not sure about the IMX477, similar generation but for consumer markets?
The HQ camera comes with IR filter so it must have some sensitivity in IR range.
There is no NOIR version?
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

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