Merge pull request #13 from godber/master

Handling standard 16 bit images (Issue #11)

basic_mer_tests.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python2.6
+# vim: set noexpandtab
+# encoding: utf-8
+"""
+basic_mer_tests.py
+
+Created by Austin Godber - 2013-01-12.
+Copyright (c) 2013 Austin Godber. All rights reserved.
+"""
+
+import os
+import unittest
+
+from pds.core.common import open_pds
+from pds.core.parser import Parser
+from pds.imageextractor import ImageExtractor
+
+
+class untitledTests(unittest.TestCase):
+	def setUp(self):
+		self.parser = Parser()
+		self.imageExtractor = ImageExtractor()
+		self.testDataPath = "../test_data/MER"
+		self.testImages = ["1F345867992EFFB0J3P1212L0M1.IMG",
+											 "1N345854840EFFB0IEP1994L0M1.IMG",
+											 "1P345688456EFFB0EJP2363L2C1.IMG"]
+		self.testImagePath = self.testDataPath + "/" + self.testImages[0]
+
+	def test_existence(self):
+		assert os.path.exists(self.testImagePath)
+
+	def test_open_pds(self):
+		"""Opening a single image without an exception"""
+		p = self.parser
+		try:
+			f = open_pds(self.testImagePath)
+			p.parse(f)
+		except:
+			raise
+
+	def test_get_labels(self):
+		"""Parsing labels returns something other than None"""
+		p = self.parser
+		labels = p.parse(open_pds(self.testImagePath))
+		self.assertNotEqual(None, labels)
+
+	def test_get_image(self):
+		"""Verify that the extracted image dimensions match those in the label"""
+		ie = self.imageExtractor
+		img, labels = ie.extract(open_pds(self.testImagePath))
+		self.assertNotEqual(None, img)
+		imageSize = map(int, (labels["IMAGE"]["LINE_SAMPLES"], labels["IMAGE"]["LINES"]))
+		self.assertEqual(tuple(imageSize), img.size)
+
+	def test_write_images(self):
+		"""docstring for test_write_image"""
+		ie = self.imageExtractor
+		for image in self.testImages:
+				img, labels = ie.extract(open_pds(self.testDataPath + '/' + image))
+				img.save(image + '.jpg')
+
+if __name__ == '__main__':
+	unittest.main()

pds/imageextractor.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+# vim: set noexpandtab
 # encoding: utf-8
 """
 imageextractor.py
@@ -8,7 +9,6 @@
 Copyright (c) 2009 Ryan Matthew Balfanz. All rights reserved.
 """
 
-
 import hashlib
 import logging
 import os
@@ -18,8 +18,10 @@
 try:
 	import Image
 except ImportError:
-		from PIL import Image
-
+	from PIL import Image
+
+import ImageMath
+
 from core.common import open_pds
 from core.parser import Parser
 from core.extractorbase import ExtractorBase, ExtractorError
@@ -30,37 +32,37 @@ class ImageExtractorError(ExtractorError):
 
 	def __init__(self, *args, **kwargs):
 		super(ExtractorError, self).__init__(*args, **kwargs)
-		
-		
+
+
 class ImageNotSupportedError(object):
 	"""docstring for ImageNotSupportedError"""
 	def __init__(self):
 		super(ImageNotSupportedError, self).__init__()
-		
-		
+
+
 class ChecksumError(ImageExtractorError):
 	"""Error raised when verification of a secure hash fails."""
 
 	def __init__(self, *args, **kwargs):
 		super(ChecksumError, self).__init__(*args, **kwargs)
-		
-		
+
+
 class ImageExtractor(ExtractorBase):
 	"""Extract an image embedded within a PDS file.
-	
+
 	Returned images are instances of the Python Imaging Library Image class.
 	As such, this module depends on PIL.
-	
-	An attached image may be extracted from by 
+
+	An attached image may be extracted from by
 	determining its location within the file and identifying its size.
 	Not all PDS images are supported at this time.
-	
+
 	Currently this module only supports FIXED_LENGTH as the RECORD_TYPE,
 	8 as the SAMPLE_BITS and either UNSIGNED_INTEGER or MSB_UNSIGNED_INTEGER as the SAMPLE_TYPE.
 	Attempts to extract an image that is not supported will result in None being returned.
-	
+
 	Simple Example Usage
-	
+
 	>>> import Image
 	>>> from imageextractor import ImageExtractor
 	>>> ie = ImageExtractor()
@@ -70,22 +72,22 @@ class ImageExtractor(ExtractorBase):
 	>>> else:
 	>>> 	print "The image was not supported."
 	"""
-	
+
 	def __init__(self, log=None, raisesChecksumError=True, raisesImageNotSupportedError=True):
 		super(ImageExtractor, self).__init__()
-		
+
 		self.log = log
 		self.raisesChecksumError = raisesChecksumError
 		self.raisesImageNotSupportedError = raisesImageNotSupportedError
 		if log:
 			self._init_logging()
 		# self.fh = None
 		# self.imageDimensions = None
-		
+
 		# self.PILSettings = {}
 		# self.PILSettings["mode"] = "L"
 		# self.PILSettings["decoder"] = "raw"
-		
+
 		# self.verifySecureHash = True
 
 	def _init_logging(self):
@@ -110,10 +112,10 @@ def _init_logging(self):
 		self.log.addHandler(stderr_hand)
 
 		self.log.debug('Initializing logger')
-		
+
 	def extract(self, source):
 		"""Extract an image from *source*.
-		
+
 		If the image is supported an instance of PIL's Image is returned, otherwise None.
 		"""
 		p = Parser()
@@ -125,11 +127,17 @@ def extract(self, source):
 			if self.log: self.log.debug("Image in '%s' is supported" % (source))
 			dim = self._get_image_dimensions()
 			loc = self._get_image_location()
+			imageSampleBits = int(self.labels['IMAGE']['SAMPLE_BITS'])
+			imageSampleType = self.labels['IMAGE']['SAMPLE_TYPE']
 			md5Checksum = self._get_image_checksum()
 			if self.log: self.log.debug("Image dimensions should be %s" % (str(dim)))
 			if self.log: self.log.debug("Seeking to image data at %d" % (loc))
 			f.seek(loc)
-			readSize = dim[0] * dim[1]
+			if imageSampleBits == 8:
+				readSize = dim[0] * dim[1]
+			elif imageSampleBits == 16:
+				readSize = dim[0] * dim[1] * 2
+			print readSize
 			if self.log: self.log.debug("Seek successful, reading data (%s)" % (readSize))
 			# rawImageData = f.readline()
 			# f.seek(-int(self.labels["RECORD_BYTES"]), os.SEEK_CUR)
@@ -148,7 +156,12 @@ def extract(self, source):
 			# The frombuffer defaults may change in a future release;
 			# for portability, change the call to read:
 			# frombuffer(mode, size, data, 'raw', mode, 0, 1).
-			img = Image.frombuffer('L', dim, rawImageData, 'raw', 'L', 0, 1)
+			if (imageSampleBits == 16) and imageSampleType == ('MSB_INTEGER'):
+				#img = Image.frombuffer('I', dim, rawImageData, 'raw', 'I;16BS', 0, 1)
+				img = Image.frombuffer('F', dim, rawImageData, 'raw', 'F;16B', 0, 1)
+				img = ImageMath.eval("convert(a/16.0, 'L')", a=img)
+			else:
+				img = Image.frombuffer('L', dim, rawImageData, 'raw', 'L', 0, 1)
 			if self.log:
 				self.log.debug("Image result: %s" % (str(img)))
 				self.log.debug("Image info: %s" % (str(img.info)))
@@ -158,22 +171,26 @@ def extract(self, source):
 			if self.log: self.log.error("Image is not supported '%s'" % (source))
 			img = None
 		f.close()
-				
+
 		return img, self.labels
-			
+
 	def _check_image_is_supported(self):
 		"""Check that the image is supported."""
 		SUPPORTED = {}
 		SUPPORTED['RECORD_TYPE'] = 'FIXED_LENGTH',
-		SUPPORTED['SAMPLE_BITS'] = 8,
-		SUPPORTED['SAMPLE_TYPE'] = 'UNSIGNED_INTEGER', 'MSB_UNSIGNED_INTEGER', 'LSB_INTEGER'
-
+		SUPPORTED['SAMPLE_BITS'] = 8, 16
+		SUPPORTED['SAMPLE_TYPE'] = ( 'UNSIGNED_INTEGER',
+				'MSB_UNSIGNED_INTEGER',
+				'LSB_INTEGER',
+				'MSB_INTEGER'
+				)
+
 		imageIsSupported = True
-				
+
 		if not self.labels.has_key('IMAGE'):
 			if self.log: self.log.warn("No image data found")
 			imageIsSupported = False
-			
+
 		recordType = self.labels['RECORD_TYPE']
 		imageSampleBits = int(self.labels['IMAGE']['SAMPLE_BITS'])
 		imageSampleType = self.labels['IMAGE']['SAMPLE_TYPE']
@@ -193,30 +210,30 @@ def _check_image_is_supported(self):
 			if self.raisesImageNotSupportedError:
 				raise ImageNotSupportedError(errorMessage)
 			imageIsSupported = False
-			
+
 		return imageIsSupported
-			
+
 	def _get_image_dimensions(self):
 		"""Return the dimensions of the image as (width, height).
-		
+
 		The image size is expected to be defined by the labels LINES_SAMPLES and LINES as width and height, respectively.
 		"""
 		imageWidth = int(self.labels['IMAGE']['LINE_SAMPLES'])
 		imageHeight = int(self.labels['IMAGE']['LINES'])
 		return imageWidth, imageHeight
-			
+
 	def _get_image_location(self):
 		"""Return the seek-able position of the image.
-		
+
 		The seek byte is defined by the ^IMAGE pointer.
 		It may be a single value or a value accompanied by its units.
-		
-		If only a single value is given the image location is given by 
+
+		If only a single value is given the image location is given by
 		the product of the (value - 1) and RECORD_BYTES.
-		
+
 		If the units are given along with the value, they must be <BYTES>.
 		The image location is given by the value.
-		
+
 		This may raise a ValueError.
 		"""
 		imagePointer = self.labels['^IMAGE'].split()
@@ -234,15 +251,15 @@ def _get_image_location(self):
 			errorMessage = ("^IMAGE contains extra information") % (imageSampleType)
 			raise ValueError(errorMessage)
 		return imageLocation
-		
+
 	def _get_image_checksum(self):
 		"""Return the md5 checksum of the image.
-		
+
 		The checksum is retrieved from self.labels['IMAGE']['MD5_CHECKSUM'].
 		This may raise a KeyError.
 		"""
 		ignoreKeyError = True
-		
+
 		md5Checksum = None
 		try:
 			md5Checksum = self.labels['IMAGE']["MD5_CHECKSUM"]
@@ -254,10 +271,10 @@ def _get_image_checksum(self):
 		else:
 			if self.log: self.log.debug("Found md5 checksum")
 			md5Checksum = md5Checksum[1:-1]
-			
+
 		return md5Checksum
-		
-		
+
+
 class ImageExtractorTests(unittest.TestCase):
 	"""Unit tests for class ImageExtractor"""
 	def setUp(self):
@@ -289,4 +306,4 @@ def test_no_exceptions(self):
 
 if __name__ == '__main__':
 	unittest.main()
-	
+

tests.py

@@ -19,7 +19,7 @@ class untitledTests(unittest.TestCase):
 	def setUp(self):
 		self.parser = Parser()
 		self.imageExtractor = ImageExtractor()
-		self.testImagePath = "./I18584006BTR.IMG"
+		self.testImagePath = "../test_data/I18584006BTR.IMG"
 		assert os.path.exists(self.testImagePath)
 
 	def test_open_pds(self):