HDR mode on the Pi 5

1

Section 9.7 of the “The Picamera2 Library” manual https://pip-assets.raspberrypi.com/categories/652-raspberry-pi-camera-module-2/documents/RP-008156-DS-2-picamera2-manual.pdf mentions features available on the Raspberry Pi 5 for capturing HDR images.

Given its brevity, I’m reproducing the section in its entirety:

“9.7. HDR mode on the Pi 5

The Raspberry Pi 5 has some in-built support for HDR, allowing its use even for non-HDR cameras.
To turn on the HDR mode, use (assuming picam2 is your Picamera2 object)

Code
import libcamera
picam2.set_controls({‘HdrMode’: libcamera.controls.HdrModeEnum.SingleExposure})

and to disable it use

Code
picam2.set_controls({‘HdrMode’: libcamera.controls.HdrModeEnum.Off})

The HDR mode can be configured in the {rpi-datasheets-url}/camera/raspberry-pi-camera-guide.pdf[Raspberry Pi Camera Tuning Guide] but which is beyond the scope of this document.

Because this HDR mode relies on the Pi 5′s TDN (Temporal Denoise) function to accumulate images, it’s important to skip a number of frames after a mode switch to allow this process to happen. When using the switch_mode_and_capture family of methods, the delay parameter should therefore be specified for this purpose, for example

Code
picam2.switch_mode_and_capture_file(capture_config, “image.jpg”, delay=10)
would allow 10 frames to be accumulated.”

The obvious question is, has anyone tried it? And if so, does it produce good results?

2

Understanding how this HDR mode works is quite difficult. Rather than the picamera2 manual, you should read this:

I started a discussion on this topic some time ago, but I didn’t pursue it further.See in this discussion how the merge is done, not much to do with HDR processing in my opinion.

1 Like
3

@dgalland Thanks for your reply.

Indeed, it doesn’t seem like an easy task. That’s why I posted the question in the group.

Hopefully, someone has already tried it and can shed some light on the matter.

Regards