colour_hdri.utilities Package

Module Contents

colour_hdri.utilities.linear_conversion(a, old_range, new_range)[source]

Performs a simple linear conversion of given array between the old and new ranges.

Parameters:
  • a (array_like) – Array to perform the linear conversion onto.
  • old_range (array_like) – Old range.
  • new_range (array_like) – New range.
Returns:
Return type:

ndarray

Examples

>>> a = np.linspace(0, 1, 10)
>>> linear_conversion(a, np.array([0, 1]), np.array([1, 10]))
array([  1.,   2.,   3.,   4.,   5.,   6.,   7.,   8.,   9.,  10.])
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
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()[source]

Reads image pixel data at Image.path attribute.

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]
insert()[source]
from_files()[source]
static from_files(image_files)[source]

Returns a ImageStack instance with given image files.

Parameters:image_files (array_like) – Image files.
Returns:
Return type:ImageStack
insert(index, value)[source]

Reimplements the MutableSequence.insert() method.

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