General

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