Multiple issues with .DNG files

imagej

#1

Hi All

I’m having a bit of fun with .DNG files.

My setup is a Moto G4 Android phone running Open Camera on the Camera2 api. Open camera produces DNG and Jpegs.

I’m trying to use Fiji Imagej with the DNGs but am having a number of issues as follows:

  1. After opening a sequence of DNGs, certain zoom factors produce a kind of ‘cross hatch’ grid on the image. If you then save these as another format (jpeg, bmp) etc then this cross hatch is still visible at some zoom factors.

Repeating the above using the Jpeg stream as a source shows no issues in the original or exported images.

  1. After opening a stream of DNGs and saving to other formats, some of the image formats come out extremely dark and look solid black. They are not solid black as adjusting the Levels in paint.net by a HUGE amount just about shows the image.

Opening as DNG and saving as TIF or PNG shows the very dark images. Re-opening the very dark images in Fiji works fine and the image looks as it should.

Opening as DNG and saving as Jpeg or BMP works as expected (the images aren’t black).

I hope this makes sense!

Thanks for reading…

Steve


Aut Correcting stack of images with differing zoom factors
#2

Hi Is there any support for my issues? I’d be very grateful to hear from anyone that jas a solution.

Cheers

Steve


#3

Good day Steve,

if you are dealing with scientific imaging, any kind of smart-phone camera is unsuited for this purpose, because these cameras do image processing in various ways that are opaque to the user. This holds, even if the camera is said to deliver RAW-images. These images are also processed.

Regards

Herbie


#4

Hi Herbie

Thanks for your reply. I’m using rooted phone with Open Camera which uses the Android Camera2 API and is very configurable, allowing pretty much all controls to be set manually. I agree the standard app (and jpeg format) does a fair amount of image processing.

Do you have any idea on my issues? I’d like to use DNGs as they are uncompressed and repeatedly processing jpegs isn’t too clever.

Cheers

Steve


#5

very configurable, allowing pretty much all controls to be set manually

As I’'ve written, don’t believe it!
Use a professional camera if you have professional image processing tasks.

processing jpegs isn’t too clever.

This holds already for acquiring JPG-compressed images, if they are meant for scientific purposes.

If BioFormats doesn’t help, look for other applications and Fora.

Regards

Herbie


#6

Hi Herbie

Thanks for the tip on BioFormats. I’ll check it out and see if I can successfully convert the dngs to TIFF LZW. That would work for me.

Just to explain. I’m not trying to apply this to scientific research. I’m doing some microscope photography and and focus stacking the images.

I’ll report back how I get on.

Thanks again for your help.

Steve