Strange pattern in sensor output


Hello everyone,

recently i took come pictures with my (old) Powershot A640.

Most of them were fine, but on a pair of them i have some strange pattern on the right side of the image. I remember this happened few times also in 2012 or so.

You can find raw (with CHDK and converted with DCRAW) and jpeg file on this link on wetransfer:

What could it be? Better seen at 100%, on the right side.

Next shots were ok.

Thank you in advance.


Here is a 100% crop. The left side is ok, the right one isn’t ok.

Camera has a CCD sensor, if it could matter.


It might be because there is a slight difference between alternating lines of green pixels on this camera. I think Raw Therapee has green equalisation to address that issue.

(Shreedhar Inamdar) #4

You can use the line noise filter in RT to remove the horizontal lines.

(Morgan Hardwood) #5

Using the latest RawTherapee development version:



Thank you all!