White Balance Issue of HQ Camera Raspberry pi

hdri
1

Hi all,

I am using an HQ camera for HDRI with Raspberry pi and have WB issue. At first, it pictured a greenish photo but by changing the awb_gain, I got a better result but not sure what should be the number to make sure about the WB of the camera. I am wondering if I should set it to auto WB mode or how to make sure about the numbers for awb_gain. Worth mentioning that I am working in a daylit space. I appreciate your help in advance.

Thanks,

2

You should use the same fixed (NOT auto) white balance setting for initial calibration as you do for capture, and you can expect the color to change with changing lighting conditions.

3

Thanks @Greg_Ward for your prompt response.

In that case, how can I make sure that the number I use is the correct number? I am using the number that is used for a sigma lens, I think, that I found online; it helped for my purpose but not sure if it is the number I should use.

I am using two cameras in space in two opposite directions (facing window and 180 opposite direction); should I use the same number for both directions?

Thanks,

4

I don’t know the number correspondences for the WB of your camera, but I generally recommend a D65 or “Daylight” WB setting, as it is the one used for the default color space.

5

Unfortunately, the Raspberry pi camera does not have the option to set it to daylight mode :frowning:

6

Well, what are the options, then? Can you set color temperature? It can’t just have “auto.”

7

To my knowledge, you can either set it to auto or put the number manually to a (red, blue) tuple of gains.

8

Well, you may be stuck using the numbers you found online, or applying a process of trial and error to arrive at suitable values. The lens should not have much effect on the coefficients for a particular white balance. You can try shooting a white piece of paper or standard gray card under daylight conditions (sunny day, paper facing upwards or towards the sun) using an array of settings to pick the one that delivers an image closest to gray.

1 Like
9

Hi Masoome,

how are you taking the images, did you write your own code for this (if so, using a specific libray?), do you use some application? In what format do you store the images? The effects sounds a bit like when taking raw-captures.

Best, Lars.

10

Hi @Lars_Grobe,

Sorry for the late response. I use Picamera lib to take JPG format pictures on Raspberry Pi OS. I just run the *.py file in a terminal.

Thanks,