Re: [Image-SIG] Auto level with PIL?
On 9/8/05, Joao S. O. Bueno Calligaris <[EMAIL PROTECTED]> wrote: > The cenonicakl reference is still the aparently out of date page at: > > www.jamesh.id.au/software/pygimp/ This looks like a way to write python scripts that run _within_ Gimp. In fact, the documentation says the system also takes care of details like the gui, and all seems like running interactively. Chris on the other hand seems like not wanting such an interactive approach. Or, to say it differently, if he's ok with triggering the thing with mouse clicks, why doesn't he simply create a Photoshop action? So, if what he really needs is batch processing of images, maybe out of a crontab or driven by the click on a web interface, he can't really use an interactive tool. If PIL is not enough, or simply he does not want to go as low level as reimplementing the algorithms himself, he could use gimp in batch mode. I found this tutorial talking about it: http://gimp.org/tutorials/Basic_Batch/ In the example it actually applies an unsharp mask to a bunch of images in a directory, so probably something very similar to what Chris needs to do. Scriptfu can be quite powerful because it's basically a program written in the Scheme language. But it's not python... :( I don't know if pygimp allows batch processing as well. If it doesn't, then I guess the only chance would be to use python to generate scheme code snippets on the fly and feed them to gimp. cheers, stefano ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
On Wednesday 07 September 2005 19:59, Ben de Luca wrote: > Could you point me at some information about the gimp scripting in > python. The only python things I found were woefully out of date. > The cenonicakl reference is still the aparently out of date page at: www.jamesh.id.au/software/pygimp/ The way the plugins are built did not change. Basically, the steps are these: make a python script, and save it in a gimp - plugins directory (you can see which are these under the preferences dialog in the GIMP) Include the module "gimpfu". At the end of your script call both gimpfu.register function, as documented in the above url, and gimpfu.main (). A call for yor script will show up in the menus in the GIMP. What is newere than these documentation is the GIMP API - but this one can be consulted on ine with the Procedural Database Browser, in the GIMP "Xtns" menu. regards! JS -><- > On 08/09/2005, at 3:12 AM, Joao S. O. Bueno Calligaris wrote: > > Hi, > > > > If you can't find an autolevel to use with PIL, maybe yyou can > > use the GIMP instead. > > It is scriptable in python as well. > > > > JS > > -><- > > > > On Wednesday 07 September 2005 14:00, Chris Barker wrote: > >> Hi all, > >> > >> I need to do something like Photoshop's Auto Level to a bunch of > >> images. Honestly, I have only a vague idea of what it does, but > >> I saw that someone posted a script to do it here about 6 years > >> ago, but I can't seem to get that code from the list archives. > >> It's also possible that someone has improved upon it in all > >> those years. Has anyone got any code for this? > >> > >> A pointer to a good description of what auto level is would be > >> nice too. > >> > >> -thanks, > >> > >> -Chris > > > > ___ > > Image-SIG maillist - Image-SIG@python.org > > http://mail.python.org/mailman/listinfo/image-sig ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
Could you point me at some information about the gimp scripting in python. The only python things I found were woefully out of date. On 08/09/2005, at 3:12 AM, Joao S. O. Bueno Calligaris wrote: > Hi, > > If you can't find an autolevel to use with PIL, maybe yyou can use > the GIMP instead. > It is scriptable in python as well. > > JS > -><- > > On Wednesday 07 September 2005 14:00, Chris Barker wrote: > >> Hi all, >> >> I need to do something like Photoshop's Auto Level to a bunch of >> images. Honestly, I have only a vague idea of what it does, but I >> saw that someone posted a script to do it here about 6 years ago, >> but I can't seem to get that code from the list archives. It's also >> possible that someone has improved upon it in all those years. Has >> anyone got any code for this? >> >> A pointer to a good description of what auto level is would be nice >> too. >> >> -thanks, >> >> -Chris >> > ___ > Image-SIG maillist - Image-SIG@python.org > http://mail.python.org/mailman/listinfo/image-sig > ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
Thanks Stefano, this make sit much more clear what's going on. I'll give this code a try. -chris -- Christopher Barker, Ph.D. Oceanographer NOAA/OR&R/HAZMAT (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception [EMAIL PROTECTED] ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
In this code all_same defaults to 0. The author says: "I find the BEST way to color/density correct an image is to first set the black/white point for each of the channels individually, so that you use the entire available dynamic range." While this is true, I must point out that you risk skewing the hue for very dark colors and very bright ones. I think setting all_same to 1 would be a more color conservative option. cheers, -stefano On 9/7/05, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > Chris Barker wrote: > > > I need to do something like Photoshop's Auto Level to a bunch of images. > > Honestly, I have only a vague idea of what it does, but I saw that > > someone posted a script to do it here about 6 years ago, but I can't > > seem to get that code from the list archives. > > this one? > > http://aspn.activestate.com/ASPN/Mail/Message/image-sig/582729 > ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
Autolevel basically works by analyzing the histogram of the image. The histogram of an 8-bit image is basically a set of 256 counters (32767 if working in 16-bit mode) for each channel. Each one counts how many bits are the in the image for the specified intensity value. A pixel with color (100, 200, 150) increments by one the 100th red counter, the 200th green one and the 150th blue one. After building the histogram, you look at the lowest value that counts at least one pixel, and the highest. Say that in your image no pixel has a colour darker than (10, 15, 7) and no one brighter than (250, 247, 200). It means that the range of your image is 7-250. Last step, you scale the values of each pixels proportionally so that 7 becomes 0, 250 becomes 255 and whatever in between is proportionally scaled. it's a rough explanation... but I hope it helps. -stefano On 9/7/05, Chris Barker <[EMAIL PROTECTED]> wrote: > Hi all, > > I need to do something like Photoshop's Auto Level to a bunch of images. > Honestly, I have only a vague idea of what it does, but I saw that > someone posted a script to do it here about 6 years ago, but I can't > seem to get that code from the list archives. It's also possible that > someone has improved upon it in all those years. Has anyone got any code > for this? > > A pointer to a good description of what auto level is would be nice too. > > -thanks, > > -Chris > > > > -- > Christopher Barker, Ph.D. > Oceanographer > > NOAA/OR&R/HAZMAT (206) 526-6959 voice > 7600 Sand Point Way NE (206) 526-6329 fax > Seattle, WA 98115 (206) 526-6317 main reception > > [EMAIL PROTECTED] > ___ > Image-SIG maillist - Image-SIG@python.org > http://mail.python.org/mailman/listinfo/image-sig > ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
Chris Barker wrote: > I need to do something like Photoshop's Auto Level to a bunch of images. > Honestly, I have only a vague idea of what it does, but I saw that > someone posted a script to do it here about 6 years ago, but I can't > seem to get that code from the list archives. this one? http://aspn.activestate.com/ASPN/Mail/Message/image-sig/582729 here's the code from that post: # adjust levels to fill histogram # Kevin Cazabon, 1999. [EMAIL PROTECTED] [EMAIL PROTECTED] def levels(data, all_same = 0, clip = 0): if data.mode not in ['RGB', 'CMYK']: return data lut = makelut(data, all_same, clip) data = data.point(lut) return data def find_hi_lo(lut, clip): min = None max = None for i in range(len(lut)): if lut[i] > clip: min = i break lut.reverse() for i in range(len(lut)): if lut[i] > clip: max = 255 - i break return min, max def scale(channels, min, max): lut = [] for i in range (channels): for i in range(256): value = int((i - min)*(255.0/float(max-min))) if value < 0: value = 0 if value > 255: value = 255 lut.append(value) return lut def makelut(data, all_same, clip): import Image histogram = data.histogram() lut = [] r, g, b, k = [], [], [], [] channels = len(histogram)/256 for i in range(256): r.append(histogram[i]) g.append(histogram[256+i]) b.append(histogram[512+i]) if channels == 4: for i in range(256): k.append(histogram[768+i]) rmin, rmax = find_hi_lo(r, clip) gmin, gmax = find_hi_lo(g, clip) bmin, bmax = find_hi_lo(b, clip) if channels == 4: kmin, kmax = find_hi_lo(k) else: kmin, kmax = 128, 128 if all_same == 1: min_max = [rmin, gmin, bmin, kmin, rmax, gmax, bmax, kmax] min_max.sort() lut = scale(channels, min_max[0], min_max[-1]) else: r_lut = scale(1, rmin, rmax) g_lut = scale(1, gmin, gmax) b_lut = scale(1, bmin, bmax) if channels == 4: k_lut = scale(1, kmin, kmax) lut = [] for i in range (256): lut.append(r_lut[i]) for i in range (256): lut.append(g_lut[i]) for i in range (256): lut.append(b_lut[i]) if channels == 4: for i in range (256): lut.append(k_lut[i]) return lut ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Auto level with PIL?
Hi, If you can't find an autolevel to use with PIL, maybe yyou can use the GIMP instead. It is scriptable in python as well. JS -><- On Wednesday 07 September 2005 14:00, Chris Barker wrote: > Hi all, > > I need to do something like Photoshop's Auto Level to a bunch of > images. Honestly, I have only a vague idea of what it does, but I > saw that someone posted a script to do it here about 6 years ago, > but I can't seem to get that code from the list archives. It's also > possible that someone has improved upon it in all those years. Has > anyone got any code for this? > > A pointer to a good description of what auto level is would be nice > too. > > -thanks, > > -Chris ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
