I did few tests with a raised-cosine filter :
http://i.imgur.com/UCppRpv.png
A0 = 1.0;
f0L = 0.02; f0H = 0.05;
A1 = 0.5;
f1L = 0.1; f1H = 0.2;
A2 = 1.0;
http://i.imgur.com/kzZxgSf.jpg
A0 = 1.0;
f0L = 0.00; f0H = 0.05;
A1 = 2.0;
f1L = 0.1; f1H = 1.0;
A2 = 0.1;
http://i.imgur.com/EqzcfYS.jpg ...
Search found 12 matches
- 2015-02-05T03:14:43-07:00
- Forum: Digital Image Processing
- Topic: Audio equalizer for images?
- Replies: 14
- Views: 86228
- 2014-04-01T05:11:33-07:00
- Forum: Digital Image Processing
- Topic: Better JPEG quantization tables?
- Replies: 84
- Views: 376295
Re: Better JPEG quantization tables?
Here is my qtable generator:
/*
Written in 2014 by Jukka Ripatti
To the extent possible under law, the author have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.
See http ...
/*
Written in 2014 by Jukka Ripatti
To the extent possible under law, the author have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.
See http ...
- 2013-02-27T19:16:18-07:00
- Forum: Digital Image Processing
- Topic: Better JPEG quantization tables?
- Replies: 84
- Views: 376295
Re: Better JPEG quantization tables?
It seems to me that ITU-T.81 Annex K.1 is often misunderstood. Many software (including libjpeg) and hardware using the tables, despite the fact that the standart says "These tables are provided as examples only and are not necessarily suitable for any particular application."
- 2013-02-27T19:06:00-07:00
- Forum: Digital Image Processing
- Topic: JPEG q-tables, 'quality', and some other image formats
- Replies: 12
- Views: 46005
Re: JPEG q-tables, 'quality', and some other image formats
Have you tried to convert images to monochrome before compression?xooyoozoo wrote:Edit: Well, I guess I missed the obvious fact that Photoshop automatically uses different quality factors for luma and chroma, and structural similarity completely focuses on luma.
Code: Select all
convert orginal.png -fx luminance grayscale.png
- 2013-02-22T14:13:01-07:00
- Forum: Digital Image Processing
- Topic: JPEG q-tables, 'quality', and some other image formats
- Replies: 12
- Views: 46005
Re: JPEG q-tables, 'quality', and some other image formats
To that end, I whipped up a small comparison using a state-of-the-art perceptual metric, IW-SSIM What program you used for this comparison? This interest me, because it could help in the development of better quantization tables.
I tried previously to develop a SSIM optimized quantization table ...
I tried previously to develop a SSIM optimized quantization table ...
- 2011-12-02T06:51:43-07:00
- Forum: Bugs
- Topic: stream corrupts files
- Replies: 9
- Views: 24289
Re: stream corrupts files
Have you tried these in Windows with 32-bit binaries?
- 2011-11-18T07:26:44-07:00
- Forum: Bugs
- Topic: stream corrupts files
- Replies: 9
- Views: 24289
- 2011-11-17T08:47:59-07:00
- Forum: Bugs
- Topic: stream corrupts files
- Replies: 9
- Views: 24289
Re: stream corrupts files
Tested on another PC (Windows 7) with http://www.imagemagick.org/download/bin ... indows.zip and the same error appears.
works without any errors.
rose: is too small for testing.
Code: Select all
convert images\logo.png image.bmp
rose: is too small for testing.
- 2011-11-16T12:57:28-07:00
- Forum: Bugs
- Topic: stream corrupts files
- Replies: 9
- Views: 24289
Re: stream corrupts files
Sorry. I tested above commands again and corruption does not happened. Maybe this bug is difficult to repeat.
This is a easier repeatable example:
stream -map rgb -storage-type short images\logo.png - | echo abc
abc
stream.exe: IDAT: CRC error `images\logo.png' @ error/png.c ...
This is a easier repeatable example:
stream -map rgb -storage-type short images\logo.png - | echo abc
abc
stream.exe: IDAT: CRC error `images\logo.png' @ error/png.c ...
- 2011-11-14T08:33:20-07:00
- Forum: Bugs
- Topic: stream corrupts files
- Replies: 9
- Views: 24289
stream corrupts files
It seems that the stream does not properly handle situations where it can not write to a file.
stream -map rgb -storage-type char *.sgi - | x264 - -o testi.mkv --demuxer raw --input-csp rgb --input-res 1280x720 --fps 50 --quiet --frames 10
raw [info]: 1280x720p 0:0 @ 50/1 fps (cfr)
resize ...
stream -map rgb -storage-type char *.sgi - | x264 - -o testi.mkv --demuxer raw --input-csp rgb --input-res 1280x720 --fps 50 --quiet --frames 10
raw [info]: 1280x720p 0:0 @ 50/1 fps (cfr)
resize ...
- 2011-05-01T05:36:41-07:00
- Forum: Bugs
- Topic: stream makes false errors if pipe does not read data
- Replies: 0
- Views: 5483
stream makes false errors if pipe does not read data
stream images\logo.png - | dir > file.txt
stream: IDAT: CRC error `images\logo.png' @ error/png.c/MagickPNGErrorHandler/1282.
stream: Corrupt image `images\logo.png' @ error/png.c/ReadPNGImage/3252.
stream: missing an image filename `images\logo.png' @ error/stream.c/StreamImageCommand/762 ...
stream: IDAT: CRC error `images\logo.png' @ error/png.c/MagickPNGErrorHandler/1282.
stream: Corrupt image `images\logo.png' @ error/png.c/ReadPNGImage/3252.
stream: missing an image filename `images\logo.png' @ error/stream.c/StreamImageCommand/762 ...
- 2011-03-22T09:32:47-07:00
- Forum: Bugs
- Topic: -colors does not work with RGBA PNG
- Replies: 1
- Views: 6331
-colors does not work with RGBA PNG
sphere.png:
http://img233.imageshack.us/img233/4008/sphereu.png
convert sphere.png -colors 50 spherecolors50.png
http://img691.imageshack.us/img691/610/spherecolors50.png
convert sphere.png PNG8:spherepng8.png
http://img833.imageshack.us/img833/6731/spherepng8.png
This works:
convert ...
http://img233.imageshack.us/img233/4008/sphereu.png
convert sphere.png -colors 50 spherecolors50.png
http://img691.imageshack.us/img691/610/spherecolors50.png
convert sphere.png PNG8:spherepng8.png
http://img833.imageshack.us/img833/6731/spherepng8.png
This works:
convert ...