Re: working with raw image files
Ok, I solved the problem with matplotlib fileobj = open(hand.raw, 'rb') data = numpy.fromfile(fileobj,dtype=np.uint16) data = numpy.reshape(data,(96,470,352)) imshow(data[:,:,40],cmap='gray') show() the error was caused by different order of data, however it still reads the dataset as half of it size. whatever. please leave the part about .raw, lets just start thinking of it from level of numpy array. I would like to visualize this data with PIL, but PIL works only with 8bit data. How could I resample my array from 16bit to 8bit? -- http://mail.python.org/mailman/listinfo/python-list
Re: working with raw image files
On 14 Cze, 22:26, MRAB pyt...@mrabarnett.plus.com wrote: Multiply the numpy array by a scaling factor, which is float(max_8bit_value) / float(max_16bit_value). could you please explain it a little? I dont understand it. like multiplying each element? -- http://mail.python.org/mailman/listinfo/python-list
Re: working with raw image files
On 15 Cze, 00:06, MRAB pyt...@mrabarnett.plus.com wrote: Yes. Something like this: fileobj = open(hand.raw, 'rb') data = numpy.fromfile(fileobj, dtype=numpy.uint16) fileobj.close() data = data * float(0xFF) / float(0x) data = numpy.array(data, dtype=numpy.uint8) data = data.reshape((96, 470, 352)) imshow(data[:, :, 40], cmap='gray') show() thank you very much, it works and now I can display this data even with Image.fromarray(). As I understand, it multiplies data elements by a fraction, so that when we have less levels (in 8uint), it can fit there? -- http://mail.python.org/mailman/listinfo/python-list
Re: working with raw image files
On 15 Cze, 01:25, Dave Angel da...@ieee.org wrote: On 01/-10/-28163 02:59 PM, kafooster wrote: On 14 Cze, 22:26, MRABpyt...@mrabarnett.plus.com wrote: Multiply the numpy array by a scaling factor, which is float(max_8bit_value) / float(max_16bit_value). could you please explain it a little? I dont understand it. like multiplying each element? You said in an earlier message to ignore the RAW format. However, if your file matches a typical camera's raw file, there are several problems: 1) the data is typically 12 to 14 bits per pixel, only rarely 16 (very expensive cameras) 2) the data does not have R, G and B values for each pixel, but only one of these. The others are generated by Bayer interpolation. 3) the data is linear (which is what the hardware produces), and traditional image data wants to be in some non-linear color space. For example, most jpegs are sRGB 8*3 bits per pixel. The first would mean that you'd need to do a lot of shifting and masking. The second would mean a pretty complex interpolation algorithm. And the third would require an exponential function at the very least. DaveA well, I am only working with grayscale MRI medical images(mainly 8 or 16bits), saved as .raw. I do not need to worry about rgb. -- http://mail.python.org/mailman/listinfo/python-list
working with raw image files
I am working on some medical image data, and I try to look into
specific slice of 3d *.raw image. I know voxels are 16 bit int, and
dimensions are 352*470*96. I checked it in some pro medical image
viewer, it is alright. However, with the code I use, I display just
white noise image.(but worked well for other, 8bit raw image).
Also, printed size is half the original size, like it was 8 bit. I
read some documentations on PIL, numpy etc but I think I just do not
understand something.
I open image data set, I change it to array, give it dimensions,
dtype, and change it to image, right? I think there is something
messed up in 'binvalues', but dont really know how to write it in
simpler way.
P.S.1
If I want to change data type to e.g. 8 bit uint, is it just change in
scipy.array? or it requires some more changes
P.S.2
Lets say I have my array of image data and want to save it to *.raw
data set. is it array.tofile?
Here is my code
import scipy as sc
from pylab import *
import array
import Image
fileobj = open(hand.raw, 'rb')
binvalues = array.array('B')
binvalues.read (fileobj, 352*470*96)
data1 = sc.array(binvalues, dtype=sc.int16)
data2 = sc.reshape(data1, (352,470,96))
fileobj.close()
print data2.size , data2.dtype
im = Image.fromarray(data2[:,:,40])
im.show()
--
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Re: working with raw image files
Wanderer: by *.raw I mean images with .raw extension, pure pixel data without header http://en.wikipedia.org/wiki/Raw_image_format That is a clear and nice code however I think Image.open cannot handle .raw since i get error image1 = Image.open(hand.raw, rb) File D:\Python27\lib\site-packages\PIL\Image.py, line 1947, in open raise ValueError(bad mode) ValueError: bad mode -- http://mail.python.org/mailman/listinfo/python-list
Re: working with raw image files
On 13 Cze, 22:52, Wanderer wande...@dialup4less.com wrote: On Jun 13, 4:41 pm, kafooster dmoze...@gmail.com wrote: Wanderer: by *.raw I mean images with .raw extension, pure pixel data without headerhttp://en.wikipedia.org/wiki/Raw_image_format That is a clear and nice code however I think Image.open cannot handle .raw since i get error image1 = Image.open(hand.raw, rb) File D:\Python27\lib\site-packages\PIL\Image.py, line 1947, in open raise ValueError(bad mode) ValueError: bad mode Try dropping the rb. I don't use it in my code. I copied it from the OP. I tried it, then it cannot identify image file -- http://mail.python.org/mailman/listinfo/python-list
