Raspberry PI HQ Camera - aaronwmorris/indi-allsky GitHub Wiki

Recommended settings

1. Use DNG RAW mode
2. Use 16-22 gain at night
3. Disable libcamera Auto-White Balance [AWB] at night
   • libcamera performs AWB by taking multiple (up to 5) exposures at a given level to calculate the proper white balance. This means a 60 second exposure can take up to 300 seconds (5 minutes!) to complete. A significant amount of time is lost between exposures.
   • The libcamera AWB is very good at correcting the color balance, therefore disabling AWB will require additional settings to try to achieve similar results.
4. Enable SCNR - Average Neutral
   • When you enable RAW [DNG] mode, the data is RAW sensor data where no processing has been applied.
   • Modern color image sensors have a color bayer matrix with two green pixels for every red and blue which will result in a overall green bias in the image.
   • The SCNR algorithm creates a synthetic green channel and does a decent job at removing the green bias.
5. Set gamma correction to 2.0
6. Stretching
   • Standard Deviation Cutoff with cutoff of 2.25
   • or Midtone Transer Function [MTF] - Shadow cutoff 0.03
7. [Optional] - Set Camera Bit depth to 16
   • DNG RAW mode only
   • The automatic bit depth detection sometimes goes haywire and will detect the wrong bit depth which will result in a dark or completely gray image.

JPEG mode

If you elect to use JPEG mode with AWB disabled, an additional configuration will be necessary.

1. Disable Color Correction Matrix [CCM]
   • A bug was recently discovered in libcamera that incorrectly applies the CCM to images when AWB is disabled. The CCM assumes a proper white balance is in place to properly color calibration.
     • https://github.com/raspberrypi/rpicam-apps/issues/784
     • https://github.com/aaronwmorris/indi-allsky/issues/1888
   • When SCNR is applied to the RPi HQ Camera jpeg images (with AWB disabled) the resulting image will have a blue bias.
   • As of Sept 2025, rpicam-apps 1.9.0 includes a new flag to disable CCM on the command line and this option is available in indi-allsky.
   • [Legacy] Instructions below

DPC "Star Eater" Algorithm

Defective Pixel Correction [DPC] is enabled by default on the Raspberry PI HQ camera (IMX477). Disabling the DPC requires 2 changes

1. Disable DPC in the imx477 kernel module (and reboot)

    echo "options imx477 dpc_enable=0" | sudo tee /etc/modprobe.d/imx477.conf
   

2. Disable DPC in tuning file

   • Raspberry Pi 5

       jq 'walk(if type == "object" and has ("rpi.dpc") then (.["rpi.dpc"].strength = 0) else . end)' /usr/share/libcamera/ipa/rpi/pisp/imx477.json > /etc/indi-allsky/imx477_no_dpc.json
     

   • Raspberry Pi 4/3

       jq 'walk(if type == "object" and has ("rpi.dpc") then (.["rpi.dpc"].strength = 0) else . end)' /usr/share/libcamera/ipa/rpi/vc4/imx477.json > /etc/indi-allsky/imx477_no_dpc.json
     

   • Add --tuning-file /etc/indi-allsky/imx477_no_dpc.json to libcamera options

Legacy DPC instructions

DPC can be disabled with the following command on older Raspbian systems

sudo vcdbg set imx477_dpc 0

Disable CCM

Add --tuning-file /etc/indi-allsky/imx477_no_ccm.json to the libcamera options after you use the jq command to disable CCM options in the custom tuning file.

Raspberry Pi 5

jq 'walk(if type == "object" and has ("rpi.ccm") then (.["x.rpi.ccm"] = .["rpi.ccm"] | del(.["rpi.ccm"])) else . end)' /usr/share/libcamera/ipa/rpi/pisp/imx477.json > /etc/indi-allsky/imx477_no_ccm.json

Raspberry Pi 4/3

jq 'walk(if type == "object" and has ("rpi.ccm") then (.["x.rpi.ccm"] = .["rpi.ccm"] | del(.["rpi.ccm"])) else . end)' /usr/share/libcamera/ipa/rpi/vc4/imx477.json > /etc/indi-allsky/imx477_no_ccm.json