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Bug #4885

closed

Redux image quality is poor / produces artifacts in imageviewer.php

Added by Neil Voss over 7 years ago. Updated over 7 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
-
Start date:
04/05/2017
Due date:
% Done:

0%

Estimated time:
Affected Version:
Appion/Leginon 3.2
Show in known bugs:
No
Workaround:

Description

When the image viewer was originally created it was taking images from 4096 to 512, which is integer scaling. With newer EM camera the scaling has become a float and introduce artifacts.

Two things I noticed to fix this:
  • scale by float then integer could help.
  • use bilinear scaling rather than default bicubic

Files

old_method.jpg (130 KB) old_method.jpg Neil Voss, 04/05/2017 12:09 AM
new_method.jpg (128 KB) new_method.jpg Neil Voss, 04/05/2017 12:09 AM
redux_testing.png (172 KB) redux_testing.png Neil Voss, 04/05/2017 07:51 AM
Actions #1

Updated by Neil Voss over 7 years ago

  • Status changed from Assigned to In Test
  • Assignee changed from Neil Voss to Anchi Cheng

new method should be faster and reduce artifacts from scaling.

Actions #3

Updated by Bridget Carragher over 7 years ago

Looks better to me for sure. But what about speed etc.?

Actions #4

Updated by Neil Voss over 7 years ago

  • File redux_testing.pdf added

By my tests, the scaling goes ~3.5X faster. Quality goes up with more noise in the images (see attachment)

We are not longer doing a cubic fit for each pixel, just a linear fit, so that goes faster. Bicubic interpolation is the default in Adobe Photoshop, but does not work well with noisy images.

Actions #6

Updated by Neil Voss over 7 years ago

  • File deleted (redux_testing.pdf)
Actions #7

Updated by Anchi Cheng over 7 years ago

  • Status changed from In Test to Closed
  • Target version set to Appion/Leginon 3.3

Works well

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