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285 lines
11 KiB
285 lines
11 KiB
# -*- coding: utf-8 -*-
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import array
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from datetime import datetime
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from nd2reader.model.metadata import Metadata
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from nd2reader.parser.base import BaseParser
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from nd2reader.driver.v3 import V3Driver
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from nd2reader.common.v3 import read_chunk
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import re
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import six
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import struct
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class V3Parser(BaseParser):
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""" Parses ND2 files and creates a Metadata and ImageReader object. """
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CHUNK_HEADER = 0xabeceda
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CHUNK_MAP_START = six.b("ND2 FILEMAP SIGNATURE NAME 0001!")
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CHUNK_MAP_END = six.b("ND2 CHUNK MAP SIGNATURE 0000001!")
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def __init__(self, fh):
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self._fh = fh
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self._metadata = None
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self._label_map = None
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@property
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def metadata(self):
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if not self._metadata:
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self._parse_metadata()
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return self._metadata
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@property
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def driver(self):
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return V3Driver(self.metadata, self._label_map, self._fh)
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def _parse_metadata(self):
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"""
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Reads all metadata.
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"""
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metadata_dict = {}
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self._label_map = self._build_label_map()
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for label in self._label_map.keys():
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if label.endswith(six.b("LV!")) or six.b("LV|") in label:
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data = read_chunk(self._fh, self._label_map[label])
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stop = label.index(six.b("LV"))
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metadata_dict[label[:stop]] = self._read_metadata(data, 1)
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height = metadata_dict[six.b('ImageAttributes')][six.b('SLxImageAttributes')][six.b('uiHeight')]
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width = metadata_dict[six.b('ImageAttributes')][six.b('SLxImageAttributes')][six.b('uiWidth')]
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channels = self._parse_channels(metadata_dict)
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date = self._parse_date(metadata_dict)
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fields_of_view = self._parse_fields_of_view(metadata_dict)
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frames = self._parse_frames(metadata_dict)
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z_levels = self._parse_z_levels(metadata_dict)
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total_images_per_channel = self._parse_total_images_per_channel(metadata_dict)
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self._metadata = Metadata(height, width, channels, date, fields_of_view, frames, z_levels, total_images_per_channel)
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def _parse_date(self, metadata_dict):
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"""
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The date and time when acquisition began.
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:rtype: datetime.datetime() or None
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"""
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for line in metadata_dict[six.b('ImageTextInfo')][six.b('SLxImageTextInfo')].values():
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line = line.decode("utf8")
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absolute_start_12 = None
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absolute_start_24 = None
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# ND2s seem to randomly switch between 12- and 24-hour representations.
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try:
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absolute_start_24 = datetime.strptime(line, "%m/%d/%Y %H:%M:%S")
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except (TypeError, ValueError):
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pass
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try:
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absolute_start_12 = datetime.strptime(line, "%m/%d/%Y %I:%M:%S %p")
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except (TypeError, ValueError):
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pass
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if not absolute_start_12 and not absolute_start_24:
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continue
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return absolute_start_12 if absolute_start_12 else absolute_start_24
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return None
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def _parse_channels(self, metadata_dict):
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"""
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These are labels created by the NIS Elements user. Typically they may a short description of the filter cube
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used (e.g. "bright field", "GFP", etc.)
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:rtype: list
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"""
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channels = []
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metadata = metadata_dict[six.b('ImageMetadataSeq')][six.b('SLxPictureMetadata')][six.b('sPicturePlanes')]
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try:
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validity = metadata_dict[six.b('ImageMetadata')][six.b('SLxExperiment')][six.b('ppNextLevelEx')][six.b('')][0][six.b('ppNextLevelEx')][six.b('')][0][six.b('pItemValid')]
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except KeyError:
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# If none of the channels have been deleted, there is no validity list, so we just make one
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validity = [True for _ in metadata]
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# Channel information is contained in dictionaries with the keys a0, a1...an where the number
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# indicates the order in which the channel is stored. So by sorting the dicts alphabetically
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# we get the correct order.
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for (label, chan), valid in zip(sorted(metadata[six.b('sPlaneNew')].items()), validity):
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if not valid:
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continue
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channels.append(chan[six.b('sDescription')].decode("utf8"))
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return channels
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def _parse_fields_of_view(self, metadata_dict):
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"""
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The metadata contains information about fields of view, but it contains it even if some fields
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of view were cropped. We can't find anything that states which fields of view are actually
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in the image data, so we have to calculate it. There probably is something somewhere, since
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NIS Elements can figure it out, but we haven't found it yet.
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:rtype: list
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"""
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return self._parse_dimension(r""".*?XY\((\d+)\).*?""", metadata_dict)
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def _parse_frames(self, metadata_dict):
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"""
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The number of cycles.
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:rtype: list
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"""
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return self._parse_dimension(r""".*?T'?\((\d+)\).*?""", metadata_dict)
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def _parse_z_levels(self, metadata_dict):
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"""
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The different levels in the Z-plane. Just a sequence from 0 to n.
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:rtype: list
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"""
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return self._parse_dimension(r""".*?Z\((\d+)\).*?""", metadata_dict)
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def _parse_dimension_text(self, metadata_dict):
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"""
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While there are metadata values that represent a lot of what we want to capture, they seem to be unreliable.
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Sometimes certain elements don't exist, or change their data type randomly. However, the human-readable text
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is always there and in the same exact format, so we just parse that instead.
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:rtype: str
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"""
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for line in metadata_dict[six.b('ImageTextInfo')][six.b('SLxImageTextInfo')].values():
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if six.b("Dimensions:") in line:
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metadata = line
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break
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else:
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return six.b("")
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for line in metadata.split(six.b("\r\n")):
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if line.startswith(six.b("Dimensions:")):
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dimension_text = line
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break
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else:
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return six.b("")
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return dimension_text
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def _parse_dimension(self, pattern, metadata_dict):
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dimension_text = self._parse_dimension_text(metadata_dict)
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if six.PY3:
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dimension_text = dimension_text.decode("utf8")
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match = re.match(pattern, dimension_text)
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if not match:
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return [0]
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count = int(match.group(1))
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return list(range(count))
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def _parse_total_images_per_channel(self, metadata_dict):
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"""
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The total number of images per channel. Warning: this may be inaccurate as it includes "gap" images.
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:rtype: int
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"""
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return metadata_dict[six.b('ImageAttributes')][six.b('SLxImageAttributes')][six.b('uiSequenceCount')]
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def _build_label_map(self):
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"""
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Every label ends with an exclamation point, however, we can't directly search for those to find all the labels
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as some of the bytes contain the value 33, which is the ASCII code for "!". So we iteratively find each label,
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grab the subsequent data (always 16 bytes long), advance to the next label and repeat.
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:rtype: dict
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"""
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label_map = {}
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self._fh.seek(-8, 2)
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chunk_map_start_location = struct.unpack("Q", self._fh.read(8))[0]
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self._fh.seek(chunk_map_start_location)
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raw_text = self._fh.read(-1)
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label_start = raw_text.index(V3Parser.CHUNK_MAP_START) + 32
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while True:
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data_start = raw_text.index(six.b("!"), label_start) + 1
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key = raw_text[label_start: data_start]
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location, length = struct.unpack("QQ", raw_text[data_start: data_start + 16])
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if key == V3Parser.CHUNK_MAP_END:
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# We've reached the end of the chunk map
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break
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label_map[key] = location
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label_start = data_start + 16
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return label_map
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def _parse_unsigned_char(self, data):
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return struct.unpack("B", data.read(1))[0]
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def _parse_unsigned_int(self, data):
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return struct.unpack("I", data.read(4))[0]
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def _parse_unsigned_long(self, data):
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return struct.unpack("Q", data.read(8))[0]
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def _parse_double(self, data):
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return struct.unpack("d", data.read(8))[0]
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def _parse_string(self, data):
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value = data.read(2)
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while not value.endswith(six.b("\x00\x00")):
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# the string ends at the first instance of \x00\x00
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value += data.read(2)
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return value.decode("utf16")[:-1].encode("utf8")
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def _parse_char_array(self, data):
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array_length = struct.unpack("Q", data.read(8))[0]
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return array.array("B", data.read(array_length))
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def _parse_metadata_item(self, data):
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"""
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Reads hierarchical data, analogous to a Python dict.
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"""
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new_count, length = struct.unpack("<IQ", data.read(12))
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length -= data.tell() - self._cursor_position
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next_data_length = data.read(length)
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value = self._read_metadata(next_data_length, new_count)
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# Skip some offsets
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data.read(new_count * 8)
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return value
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def _get_value(self, data, data_type):
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"""
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ND2s use various codes to indicate different data types, which we translate here.
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"""
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parser = {1: self._parse_unsigned_char,
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2: self._parse_unsigned_int,
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3: self._parse_unsigned_int,
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5: self._parse_unsigned_long,
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6: self._parse_double,
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8: self._parse_string,
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9: self._parse_char_array,
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11: self._parse_metadata_item}
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return parser[data_type](data)
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def _read_metadata(self, data, count):
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"""
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Iterates over each element some section of the metadata and parses it.
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"""
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data = six.BytesIO(data)
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metadata = {}
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for _ in range(count):
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self._cursor_position = data.tell()
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header = data.read(2)
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if not header:
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# We've reached the end of some hierarchy of data
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break
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if six.PY3:
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header = header.decode("utf8")
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data_type, name_length = map(ord, header)
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name = data.read(name_length * 2).decode("utf16")[:-1].encode("utf8")
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value = self._get_value(data, data_type)
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if name not in metadata.keys():
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metadata[name] = value
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else:
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if not isinstance(metadata[name], list):
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# We have encountered this key exactly once before. Since we're seeing it again, we know we
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# need to convert it to a list before proceeding.
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metadata[name] = [metadata[name]]
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# We've encountered this key before so we're guaranteed to be dealing with a list. Thus we append
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# the value to the already-existing list.
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metadata[name].append(value)
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return metadata
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