Re: Re: bitmap with bit depth 1

*To*: mathgroup at smc.vnet.net*Subject*: [mg104525] Re: [mg104441] Re: [mg104399] bitmap with bit depth 1*From*: "van der Burgt, Maarten" <Maarten.VanDerBurgt at icos.be>*Date*: Tue, 3 Nov 2009 02:53:23 -0500 (EST)*References*: <200910300719.CAA27777@smc.vnet.net> <200910310655.BAA13399@smc.vnet.net>

Hallo, Thanks for the lovely image. It does seem to work with the portable bitmap format. However, I do indeed need the Windows BMP format (the tools I will be working with are simply configured that way). For the Windows BMP format, generating an image bit depth of 1 bit/Channel does not work in Mathematica. So any suggestions are still welcome. Has anyone seen an intermittent problem importing BMP files? As: Import["test4.bmp"] Import::fmterr: Cannot import data as BMP format. >> I have not been able yet to work out under what conditions this problem shows up. Sometimes the problem is simply gone without (me seeing) any reason. - adding "BMP" in the import argument does not help - having the file local (C:\\ or C:\Users\maarten\Documents) or on the network does not make a difference. regards and thanks for your help, Maarten -----Original Message----- From: Patrick Scheibe [mailto:pscheibe at trm.uni-leipzig.de] Sent: Saturday, 31 October, 2009 07:55 To: mathgroup at smc.vnet.net Subject: [mg104525] [mg104441] Re: [mg104399] bitmap with bit depth 1 Hi, has it to be a bmp? If not then Image[Reverse@ Table[If[(x^2 + y^2 - 1)^3 - x^2 y^3 > 0.0, 0, 1], {y, -2, 2, 4/255.}, {x, -2, 2, 4/255.}], "Bit"] Export["~/tmp/binimg.pbm", %] {ImageType[#], ImageChannels[#], ImageDimensions[#]} &@Import[%] should help. Cheers Patrick On Fri, 2009-10-30 at 02:19 -0500, van der Burgt, Maarten wrote: > Hallo, > > > > Using Mathematica 7.0.1 for Windows, I want to create binary bitmap > (Windows BMP format) images with a bit depth of 1 (generally grey scale > or color bitmap images have a bit depth of 8 or 24) > > > > Here is my data: > > > > dat =RandomInteger[{0,1},{200,200}] > > > > The image generated from it looks ok: > > > > im = Image[dat,"Bit"] > > > > The right mouse click on the image and selecting Image Mode indeed tells > me the image is binary with a bit depth of 1 bit/Channel. As does: > > > > {ImageChannels[im], BinaryImageQ[im],ImageType[im]} > > {1,True,Bit} > > > > But all the images exported: > > Export["test1.bmp",im]; > > Export["test2.bmp",im, "ColorDepth"=AE1]; > > Export["test3.bmp",im, "BitDepth"=AE1]; > > Export["test4.bmp",im, "BitDepth"=AE1,"ColorDepth"=AE1]; > > > > are 8 bit greyscale images. > > Saving the image via the right mouse click on the image and choosing > =93Save Image As..=94 saves a 24 bit image. > > > > I current solution is the use of another package to reduce the bit > depth, but this is not satisfactory. > > > > Am I doing something wrong here or is Mathematica failing here? > > > > On top of this, I cannot import these image back into mathematica: > > > > Import["test4.bmp" ] > > Import::fmterr: Cannot import data as \[NoBreak]BMP\[NoBreak] format. > =87 = > <http://reference.wolfram.com/mathematica/ref/message/Import/fmterr.html > > > $Failed > > > > Any help is appreciated. > > > > regards > > > > Maarten > > >