colour_hdri.utilities Package¶

Sub-Modules¶

Module Contents¶

colour_hdri.utilities.vivification()[source]¶

Implements supports for vivification of the underlying dict like data-structure, magical!

Returns:
Return type:	defaultdict

Examples

>>> vivified = vivification()
>>> vivified['my']['attribute'] = 1
>>> vivified['my']  # doctest: +ELLIPSIS
defaultdict(<function vivification at 0x...>, {u'attribute': 1})
>>> vivified['my']['attribute']
1

colour_hdri.utilities.vivified_to_dict(vivified)[source]¶

Converts given vivified data-structure to dictionary.

Parameters:	vivified (defaultdict) – Vivified data-structure.
Returns:
Return type:	dict

Examples

>>> vivified = vivification()
>>> vivified['my']['attribute'] = 1
>>> vivified_to_dict(vivified)
{u'my': {u'attribute': 1}}

colour_hdri.utilities.path_exists(path)[source]¶

Returns if given path exists.

Parameters:	path (unicode) – Path to check the existence.
Returns:
Return type:	bool

Examples

>>> path_exists(__file__)
True
>>> path_exists('')
False

colour_hdri.utilities.filter_files(directory, extensions)[source]¶

Filters given directory for files matching given extensions.

Parameters:	directory (unicode) – Directory to filter. extensions (tuple or list) – Extensions to filter on.
Returns:	Filtered files.
Return type:	list

class colour_hdri.utilities.ExifTag[source]¶

Bases: colour_hdri.utilities.exif.ExifTag

Hunt colour appearance model induction factors.

Parameters:	group (unicode, optional) – Exif tag group name. name (unicode, optional) – Exif tag name. value (object, optional) – Exif tag value. identifier (numeric, optional) – Exif tag identifier.

Returns a new instance of the ExifTag class.

colour_hdri.utilities.parse_exif_string(exif_tag)[source]¶

Parses given exif tag assuming it is a string and return its value.

Parameters:	exif_tag (ExifTag) – Exif tag to parse.
Returns:	Parsed exif tag value.
Return type:	unicode

colour_hdri.utilities.parse_exif_numeric(exif_tag, dtype=<class 'numpy.float64'>)[source]¶

Parses given exif tag assuming it is a numeric type and return its value.

Parameters:	exif_tag (ExifTag) – Exif tag to parse. dtype (object, optional) – Return value data type.
Returns:	Parsed exif tag value.
Return type:	numeric

colour_hdri.utilities.parse_exif_fraction(exif_tag, dtype=<class 'numpy.float64'>)[source]¶

Parses given exif tag assuming it is a fraction and return its value.

Parameters:	exif_tag (ExifTag) – Exif tag to parse. dtype (object, optional) – Return value data type.
Returns:	Parsed exif tag value.
Return type:	numeric

colour_hdri.utilities.parse_exif_array(exif_tag, dtype=<class 'numpy.float64'>, shape=None)[source]¶

Parses given exif tag assuming it is an array and return its value.

Parameters:	exif_tag (ExifTag) – Exif tag to parse. dtype (object, optional) – Return value data type. shape (array_like, optional) – Shape of
Returns:	Parsed exif tag value.
Return type:	ndarray

colour_hdri.utilities.parse_exif_data(data)[source]¶

Parses given exif data output from exiftool.

Parameters:	data (unicode) – Exif data.
Returns:	Parsed exif data.
Return type:	list

colour_hdri.utilities.read_exif_tags(image)[source]¶

Returns given image exif image tags.

Parameters:	image (unicode) – Image file.
Returns:	Exif tags.
Return type:	defaultdict

colour_hdri.utilities.copy_exif_tags(source, target)[source]¶

Copies given source image file exif tag to given image target.

Parameters:	source (unicode) – Source image file. target (unicode) – Target image file.
Returns:	Definition success.
Return type:	bool

colour_hdri.utilities.update_exif_tags(images)[source]¶

Updates given images siblings images pairs exif tags.

Parameters:	images (list) – Image files to update.
Returns:	Definition success.
Return type:	bool

colour_hdri.utilities.delete_exif_tags(image)[source]¶

Deletes all given image exif tags.

Parameters:	image (unicode) – Image file.
Returns:	Definition success.
Return type:	bool

colour_hdri.utilities.read_exif_tag(image, tag)[source]¶

Returns given image exif tag value.

Parameters:	image (unicode) – Image file. tag (unicode) – Tag.
Returns:	Tag value.
Return type:	unicode

colour_hdri.utilities.write_exif_tag(image, tag, value)[source]¶

Sets given image exif tag value.

Parameters:	image (unicode) – Image file. tag (unicode) – Tag. value (unicode) – Value.
Returns:	Definition success.
Return type:	bool

colour_hdri.utilities.exposure_value(f_number, exposure_time, iso)[source]¶

Computes the exposure value from given image FNumber, Exposure Time and ISO values.

Parameters:	f_number (array_like) – Image FNumber. exposure_time (array_like) – Image Exposure Time. iso (array_like) – Image ISO.
Returns:	Image exposure value.
Return type:	ndarray

Examples

>>> exposure_value(8, 1, 100)
6.0

colour_hdri.utilities.adjust_exposure(a, EV)[source]¶

Adjusts given array exposure using given \(EV\) exposure value.

Parameters:	a (array_like) – Array to adjust the exposure. EV (numeric) – Exposure adjustment value.
Returns:	Exposure adjusted array.
Return type:	ndarray

Examples

>>> adjust_exposure(np.array([0.25, 0.5, 0.75, 1]), 1)
array([ 0.5,  1. ,  1.5,  2. ])

colour_hdri.utilities.average_luminance(f_number, exposure_time, iso, k=12.5)[source]¶

Computes the average luminance from given image FNumber, Exposure Time and ISO values.

Parameters:	f_number (array_like) – Image FNumber. exposure_time (array_like) – Image Exposure Time. iso (array_like) – Image ISO. k (numeric, optional) – Reflected light calibration constant \(K\).
Returns:	Image average luminance.
Return type:	ndarray

References

[1]	Wikipedia. (n.d.). EV as a measure of luminance and illuminance. Retrieved November 14, 2015, from https://en.wikipedia.org/wiki/Exposure_value#EV_as_a_measure_of_luminance_and_illuminance

Examples

>>> average_luminance(8, 1, 100)
0.125

class colour_hdri.utilities.Metadata[source]¶

Bases: colour_hdri.utilities.image.Metadata

Defines the base object for storing exif metadata relevant to HDRI / radiance image generation.

Parameters:	f_number (array_like) – Image FNumber. exposure_time (array_like) – Image Exposure Time. iso (array_like) – Image ISO. black_level (array_like) – Image Black Level. white_level (array_like) – Image White Level. white_balance_multipliers (array_like) – Image white balance multipliers, usually the As Shot Neutral matrix.

class colour_hdri.utilities.Image(path=None, data=None, metadata=None)[source]¶

Bases: object

Defines the base object for storing an image along its path, pixel data and metadata needed for HDRI / radiance images generation.

Parameters:	path (unicode, optional) – Image path. data (array_like, optional) – Image pixel data array. metadata (Metadata, optional) – Image exif metadata.

path¶

data¶

metadata¶

read_data()[source]¶

read_metadata()[source]¶

data

Property for self._data private attribute.

Returns:	self._data.
Return type:	unicode

metadata

Property for self._metadata private attribute.

Returns:	self._metadata.
Return type:	unicode

path

Property for self._path private attribute.

Returns:	self._path.
Return type:	unicode

read_data(decoding_cctf=None)[source]

Reads image pixel data at Image.path attribute.

Parameters:	decoding_cctf (object, optional) – Decoding colour component transfer function (Decoding CCTF) or electro-optical transfer function (EOTF / EOCF).
Returns:	Image pixel data.
Return type:	ndarray

read_metadata()[source]

Reads image relevant exif metadata at Image.path attribute.

Returns:	Image relevant exif metadata.
Return type:	Metadata

class colour_hdri.utilities.ImageStack[source]¶

Bases: collections.abc.MutableSequence

Defines a convenient stack storing a sequence of images for HDRI / radiance images generation.

ImageStack()¶

__init__()[source]¶

__getitem__()[source]¶

__setitem__()[source]¶

__delitem__()[source]¶

__len__()[source]¶

__getattr__()[source]¶

__setattr__()[source]¶

sort()[source]¶

insert()[source]¶

from_files()[source]¶

static from_files(image_files, decoding_cctf=None)[source]

Returns a ImageStack instance with given image files.

Parameters:	image_files (array_like) – Image files. decoding_cctf (object, optional) – Decoding colour component transfer function (Decoding CCTF) or electro-optical transfer function (EOTF / EOCF).
Returns:
Return type:	ImageStack

insert(index, value)[source]

Reimplements the MutableSequence.insert() method.

Parameters:	index (int) – Item index. value (object) – Item value.

sort(key=None)[source]

Sorts the underlying data structure.

Parameters:	key (callable) – Function of one argument that is used to extract a comparison key from each data structure.