Search found 109 matches

by rnbc
2011-07-20T18:38:40-07:00
Forum: Digital Image Processing
Topic: Image resizing with LCD sub-pixel awareness (aka ClearType)
Replies: 18
Views: 68481

Re: Image resizing with LCD sub-pixel awareness (aka ClearTy

Well, I was not asking for any "support", since it's already supported with the use of current operators :) I was only discussing how to do it, and optimize it, within the current API ;) BTW, I know it's patented, but that's a bunch of specific implementations, not the idea in general. Both Apple, A...
by rnbc
2011-07-20T17:05:26-07:00
Forum: Digital Image Processing
Topic: Image resizing with LCD sub-pixel awareness (aka ClearType)
Replies: 18
Views: 68481

Image resizing with LCD sub-pixel awareness (aka ClearType)

Hi! I was testing how LCD sub-pixel awareness could enhance images when they are resampled to smaller sizes. This is like ClearType, but for photos. For that effect I used the following commands, you might find useful. For normal resizing: convert input.tif -depth 16 -gamma 0.5 -filter Mitchell -res...
by rnbc
2010-09-27T14:45:31-07:00
Forum: Users
Topic: Knowing which chroma-subsampling was used in a JPEG
Replies: 4
Views: 16649

Re: Knowing which chroma-subsampling was used in a JPEG

Many thanks!

Weird as it may seem I hadn't seen the -verbose option (duh!!!) when looking at the -help output... :roll:
by rnbc
2010-09-27T08:20:10-07:00
Forum: Users
Topic: Knowing which chroma-subsampling was used in a JPEG
Replies: 4
Views: 16649

Knowing which chroma-subsampling was used in a JPEG

Hello!

Is there any way, with identify for example, of knowing which chroma-subsampling was used in a certain JPEG file?

Thanks.
by rnbc
2010-07-15T06:41:26-07:00
Forum: Users
Topic: Exchanging channels with a single command?
Replies: 5
Views: 10696

Re: Exchanging channels with a single command?

Found it!

Code: Select all

convert SDIMa_19045_16bit_master.ppm -color-matrix '0 0 1, 1 0 0, 0 1 0' SDIMa_19045brg_16bit_master.ppm
Etc...
by rnbc
2010-07-15T06:28:07-07:00
Forum: Users
Topic: Exchanging channels with a single command?
Replies: 5
Views: 10696

Re: Exchanging channels with a single command?

Hum... it works, but I don't understand how :(

What if I want other orders, like rbg, grb, etc...? :?
by rnbc
2010-07-15T04:55:14-07:00
Forum: Users
Topic: Exchanging channels with a single command?
Replies: 5
Views: 10696

Exchanging channels with a single command?

Hi! I feel this is a stupid question, but since I'm stuck in it... let's ask anyway :D How can I exchange channels in a single convert command? convert SDIMa_19045_16bit_master.ppm -channel Red -fx b -channel Green -fx r -channel Blue -fx g +channel SDIMa_19045brg_16bit_master.ppm This won't work, b...
by rnbc
2010-05-23T13:20:43-07:00
Forum: Bugs
Topic: Regression in bit depth reduction?
Replies: 10
Views: 20993

Re: Regression in bit depth reduction?

Well, bit-depth (or shall I say quantum?) conversion has been changed lately, exactly because of a slight bias it was introducing. But that was only in the HDRI version, I think. At least that's were I detected the bug. Apparently the explicit conversion is now working fine as far as I can tell, but...
by rnbc
2010-05-18T15:00:44-07:00
Forum: Bugs
Topic: HDRI - -auto-level not working
Replies: 7
Views: 14905

Re: HDRI - -auto-level not working

Hum... well, in fact I never tested with other HDR input formats apart from EXR... so it was a bug in EXR after all, right?
by rnbc
2010-05-17T09:47:31-07:00
Forum: Bugs
Topic: HDRI - -auto-level not working
Replies: 7
Views: 14905

Re: HDRI - -auto-level not working

It works fine now, thanks again!
by rnbc
2010-05-16T18:42:23-07:00
Forum: Bugs
Topic: HDRI - -auto-level not working
Replies: 7
Views: 14905

HDRI - -auto-level not working

Hello again! It seems that probably while solving the quanta problems something has broke in the -auto-level command in the HDRI-enabled version... ~/ImageMagick-6.6.1-5/installed/bin/convert input.exr -auto-level -gamma 2.0 -depth 8 -interlace line -quality 98 -sampling-factor 1x1 output_ok.jpg htt...
by rnbc
2010-05-10T04:38:21-07:00
Forum: Bugs
Topic: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm
Replies: 24
Views: 43398

Re: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm

Seems to be working now, and the code makes sense. Both good things :) I did a small cleanup in quantum-private.h, you can check it at http://rnbc.dyndns.org/pub/imagemagick_quanta/002/ It's only a cleanup, except for line 587. I also checked conversion to/from floating point EXR, and it works just ...
by rnbc
2010-05-09T07:52:21-07:00
Forum: Bugs
Topic: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm
Replies: 24
Views: 43398

Re: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm

By the current definition in http://rnbc.dyndns.org/pub/imagemagick_quanta/001/ when I go from 8_bit_pgm to 16_bit_pgm, in a quantum=65535 version this should happen: From magick/quantum-private.h static inline Quantum ScaleCharToQuantum(const unsigned char value) { #if !defined(MAGICKCORE_HDRI_SUPP...
by rnbc
2010-05-08T21:30:32-07:00
Forum: Bugs
Topic: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm
Replies: 24
Views: 43398

Re: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm

I changed the code again, it at http://rnbc.dyndns.org/pub/imagemagick_quanta/001/, but don't use it because that one has the same error we had one week ago :P I think the rules I stated for conversion are sound, we just need to apply them correctly, and I seem unable to do it right now... tomorrow ...
by rnbc
2010-05-08T20:23:45-07:00
Forum: Bugs
Topic: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm
Replies: 24
Views: 43398

Re: HDRI - Statistic bias in convertion16bit.ppm to 8bit.ppm

Thanks for the detailed response. We'll apply these patches to ImageMagick 6.6.1-8 and verify ImageMagick is returning correct results for HDRI. We'll need another day to confirm. No please... the patch is broken in the conversion from 8-->16 (at least!). I just checked with a PPM_8bit into PPM_16b...