> For the complete documentation index, see [llms.txt](https://docs.terraref.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.terraref.org/user-manual/data-products/fluorescence-intensity-imaging.md).

# Fluorescence intensity imaging

## Summary

Fluorescence intensity data is collected using the PSII camera.

Each measurement produces 102 bin files. The first (index 0) is an image taken right before the LED are switched on (dark reference). Frame 1 to 100 are the 100 images taken, with the LEDs on. In binary file 102 (index 101) is a list with the timestamps of each frame of the 100 frames.

Right now the LED on timespan is 1s thus the first 50 frames are taken with LEDs on the latter 50 frames with LED off.

![](/files/-MTbNAFIXpLx6XfgNuqo)

![](/files/-MTbN6j48oIg-xb_7CsJ)

## Raw data access

Fluorescence intensity data is available via Clowder and Globus:

* **Clowder**:  \_\_[ps2Top collection](https://terraref.ncsa.illinois.edu/clowder/collection/58714b584f0cc129fb5ea660)
* **Globus paths**:  
  * `/raw_data/ps2top`
  * `/Level_1/ps2_png/` 
* **Sensor information**: [LemnaTec PSII](https://terraref.ncsa.illinois.edu/clowder/datasets/5873a84b4f0cad7d8131a73d)
* **Code on GitHub**: [**Multispectral extractor**](https://github.com/terraref/extractors-multispectral)

## See also

Herritt, Matthew T., et al. "Chlorophyll fluorescence imaging captures photochemical efficiency of grain sorghum (Sorghum bicolor) in a field setting." Plant Methods 16.1 (2020): 1-13.