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Source code for imaging.images2ims

# -*- coding: utf-8 -*-
#   Copyright (C) 2012, Almar Klein
#
#   This code is subject to the (new) BSD license:
#
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""" Module images2ims

Use PIL to create a series of images.

"""

import os

try:
    import numpy as np
except ImportError:
    np = None

try:
    import PIL
except ImportError:
    PIL = None


[docs]def checkImages(images): """Check numpy images and correct intensity range etc. The same for all movie formats. :param images: """ # Init results images2 = [] for im in images: if PIL and isinstance(im, PIL.Image.Image): # We assume PIL images are allright images2.append(im) elif np and isinstance(im, np.ndarray): # Check and convert dtype if im.dtype == np.uint8: images2.append(im) # Ok elif im.dtype in [np.float32, np.float64]: theMax = im.max() if theMax > 128 and theMax < 300: pass # assume 0:255 else: im = im.copy() im[im < 0] = 0 im[im > 1] = 1 im *= 255 images2.append(im.astype(np.uint8)) else: im = im.astype(np.uint8) images2.append(im) # Check size if im.ndim == 2: pass # ok elif im.ndim == 3: if im.shape[2] not in [3, 4]: raise ValueError('This array can not represent an image.') else: raise ValueError('This array can not represent an image.') else: raise ValueError('Invalid image type: ' + str(type(im))) # Done return images2
def _getFilenameParts(filename): if '*' in filename: return tuple(filename.split('*', 1)) else: return os.path.splitext(filename) def _getFilenameWithFormatter(filename, N): # Determine sequence number formatter formatter = '%04i' if N < 10: formatter = '%i' elif N < 100: formatter = '%02i' elif N < 1000: formatter = '%03i' # Insert sequence number formatter part1, part2 = _getFilenameParts(filename) return part1 + formatter + part2 def _getSequenceNumber(filename, part1, part2): # Get string bit seq = filename[len(part1):-len(part2)] # Get all numeric chars seq2 = '' for c in seq: if c in '0123456789': seq2 += c else: break # Make int and return return int(seq2)
[docs]def writeIms(filename, images): """Export movie to a series of image files. If the filenenumber contains an asterix, a sequence number is introduced at its location. Otherwise the sequence number is introduced right before the final dot. To enable easy creation of a new directory with image files, it is made sure that the full path exists. Images should be a list consisting of PIL images or numpy arrays. The latter should be between 0 and 255 for integer types, and between 0 and 1 for float types. :param filename: :param images: """ # Check PIL if PIL is None: raise RuntimeError("Need PIL to write series of image files.") # Check images images = checkImages(images) # Get dirname and filename filename = os.path.abspath(filename) dirname, filename = os.path.split(filename) # Create dir(s) if we need to if not os.path.isdir(dirname): os.makedirs(dirname) # Insert formatter filename = _getFilenameWithFormatter(filename, len(images)) # Write seq = 0 for frame in images: seq += 1 # Get filename fname = os.path.join(dirname, filename % seq) # Write image if np and isinstance(frame, np.ndarray): frame = PIL.Image.fromarray(frame) frame.save(fname)
[docs]def readIms(filename, asNumpy=True): """ readIms(filename, asNumpy=True) Read images from a series of images in a single directory. Returns a list of numpy arrays, or, if asNumpy is false, a list if PIL images. :param filename: :param bool asNumpy: """ # Check PIL if PIL is None: raise RuntimeError("Need PIL to read a series of image files.") # Check Numpy if asNumpy and np is None: raise RuntimeError("Need Numpy to return numpy arrays.") # Get dirname and filename filename = os.path.abspath(filename) dirname, filename = os.path.split(filename) # Check dir exists if not os.path.isdir(dirname): raise IOError('Directory not found: '+str(dirname)) # Get two parts of the filename part1, part2 = _getFilenameParts(filename) # Init images images = [] # Get all files in directory for fname in os.listdir(dirname): if fname.startswith(part1) and fname.endswith(part2): # Get sequence number nr = _getSequenceNumber(fname, part1, part2) # Get Pil image and store copy (to prevent keeping the file) im = PIL.Image.open(os.path.join(dirname, fname)) images.append((im.copy(), nr)) # Sort images images.sort(key=lambda x: x[1]) images = [im[0] for im in images] # Convert to numpy if needed if asNumpy: images2 = images images = [] for im in images2: # Make without palette if im.mode == 'P': im = im.convert() # Make numpy array a = np.asarray(im) if len(a.shape) == 0: raise MemoryError("Too little memory to convert PIL image to array") # Add images.append(a) # Done return images

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