Search found 188 matches
- 2012-07-26T02:50:35-07:00
- Forum: Users
- Topic: best downsampling method for DSLR photographs
- Replies: 273
- Views: 475149
Re: best downsampling method for DSLR photographs
Fred: Your observations jive with "why" Henry tried EWA Catmull-Rom: To give "pixel peepers" all the sharpness they crave. His context was downsampling, but still. Hey, I thought I had made myself clear in some posts that I prefer EWA Lagrange over EWA Catrom for downsizing in p...
- 2012-07-19T23:22:31-07:00
- Forum: Digital Image Processing
- Topic: future of image enlargement?
- Replies: 61
- Views: 158974
Re: future of image enlargement?
Isn't "Y" of XYZ linear but "L" of LAB nonlinear?
- 2012-07-18T19:34:15-07:00
- Forum: Digital Image Processing
- Topic: "Sigmoidal" minimization of resampling filter haloing & blur
- Replies: 136
- Views: 340403
Re: "Sigmoidal" minimization of resampling filter haloing
To me, downsampling in linear RGB with sigmoidal minimization looks much like downsampling in sRGB plus cooked highlights. I think it is better suited for upsampling.NicolasRobidoux wrote:@Henry: I checked downsampling with the Nokia picture and it looks like linear light wins, as usual.
- 2012-07-18T05:26:43-07:00
- Forum: Digital Image Processing
- Topic: "Sigmoidal" minimization of resampling filter haloing & blur
- Replies: 136
- Views: 340403
Re: "Sigmoidal" minimization of resampling filter haloing
Henry: I enlarged the small version of the image (..._m) 400% and I see no colour drift. I think you are using a version of IM with the sigmoidal-contrast "bug". I copied the wrong commands and it's now corrected. I was doing downsizing of the original version and see if this sigmoidal te...
- 2012-07-18T02:04:04-07:00
- Forum: Digital Image Processing
- Topic: "Sigmoidal" minimization of resampling filter haloing & blur
- Replies: 136
- Views: 340403
Re: "Sigmoidal" minimization of resampling filter haloing
Seems sigmoidal-downsizing increases the brightness of all interpolated areas. Try it on http://www.dcfever.com/phones/viewsamples.php?set=755&picture=7234 , the buildings over the other side of the harbour looks brighter and the tall building on the left looks more "cooked". convert.e...
- 2012-07-17T19:47:52-07:00
- Forum: Digital Image Processing
- Topic: future of image enlargement?
- Replies: 61
- Views: 158974
Re: future of image enlargement?
Let me try Avisynth+NNEDI3+EEDI3 tonight.NicolasRobidoux wrote:I think that my worries about high contrast leading to colour drift were just that?
P.S. No, they are not: It depends on the sharpness of the input image.
- 2012-07-12T00:16:26-07:00
- Forum: Digital Image Processing
- Topic: "Sigmoidal" minimization of resampling filter haloing & blur
- Replies: 136
- Views: 340403
Re: "Sigmoidal" minimization of resampling filter haloing
The overall image will become darker too, not just halos. Try downsizing a photo of cactus.
- 2012-07-11T19:29:11-07:00
- Forum: Digital Image Processing
- Topic: [SOLVED] Donate a high quality raw image to science?
- Replies: 67
- Views: 158614
Re: [SOLVED] Donate a high quality raw image to science?
It looks great! Hope it would support my Panasonic GX1 in some future.
http://www.my-spot.com/RHC/RHC_Cameras.htm
http://www.my-spot.com/RHC/RHC_Cameras.htm
- 2012-07-11T09:25:46-07:00
- Forum: Users
- Topic: best downsampling method for DSLR photographs
- Replies: 273
- Views: 475149
Re: best downsampling method for DSLR photographs
Henry's -gamma trick that adds acutance. No, that gamma trick is intended to purposely obtain darker interpolated value, which is much welcomed when downsizing lines or characters on a light background. When the background is dark and the content is light, I do the opposite. Edit: And the negate-ne...
- 2012-07-10T17:16:59-07:00
- Forum: Users
- Topic: best downsampling method for DSLR photographs
- Replies: 273
- Views: 475149
Re: best downsampling method for DSLR photographs
Some preliminary downsize testing with the Astro/HDRI binary: while EWALanczos3Sharpest is nearly as sharp as EWALanczos4Sharpest, it seems to ring much less (or acutance?), especially for sharp CG pictures. When I really need acutance, I will use EWA-Lagrange. EWALanczos4Sharpest is sitting somewhe...
- 2012-07-09T23:21:59-07:00
- Forum: Digital Image Processing
- Topic: Image resizing with LCD sub-pixel awareness (aka ClearType)
- Replies: 18
- Views: 80589
Re: Image resizing with LCD sub-pixel awareness (aka ClearTy
One surprising result is that the HDRI enabled binary at http://blog.astrophotographytargets.com/ is producing sharper and more contrasty images (both -gamma and -colorspace tested) than normal Q16 binary with the above textual image. Tiny difference but noticeable. I believe such test cases are cha...
- 2012-07-09T19:01:31-07:00
- Forum: Users
- Topic: best downsampling method for DSLR photographs
- Replies: 273
- Views: 475149
Re: best downsampling method for DSLR photographs
It's http://www.imagemagick.org/Usage/windows/ that directs me to that astrophotography blog.
Anyway, I will see if I can compile a more recent version of IM6+HDRI+FFTW with mingw@amd64.
Anyway, I will see if I can compile a more recent version of IM6+HDRI+FFTW with mingw@amd64.
- 2012-07-09T16:38:45-07:00
- Forum: Users
- Topic: best downsampling method for DSLR photographs
- Replies: 273
- Views: 475149
Re: best downsampling method for DSLR photographs
With a very recent version of ImageMagick 7, the linear light versions of these schemes are .... With a recent enough version of ImageMagick 6, just replace "magick" by "convert". I am using the stock binaries at http://www.imagemagick.org/script/binary-releases.php#windows . So...
- 2012-07-07T08:50:07-07:00
- Forum: Users
- Topic: Gamma correction for JPG file
- Replies: 7
- Views: 17785
Re: Gamma correction for JPG file
Why not "-colorspace RGB". It converts your image to linear RGB for further operations.
sRGB is very similar to gamma 2.2, but not exactly the same. Not sure about AdobeRGB (some DC produces AdobeRGB instead of sRGB).
sRGB is very similar to gamma 2.2, but not exactly the same. Not sure about AdobeRGB (some DC produces AdobeRGB instead of sRGB).
- 2012-07-07T02:10:18-07:00
- Forum: Digital Image Processing
- Topic: Image resizing with LCD sub-pixel awareness (aka ClearType)
- Replies: 18
- Views: 80589
Re: Image resizing with LCD sub-pixel awareness (aka ClearTy
It seems to work better with B/W textual materials. 1000x500 picture with contents quoted from: http://zh.wikipedia.org/wiki/%E8%9F%B9%E7%8A%B6%E6%98%9F%E4%BA%91 http://i1249.photobucket.com/albums/hh512/henhen456/msg2.png "Plain" resize to 200x100: http://i1249.photobucket.com/albums/hh51...