Skip to content

Commit

Permalink
Added stronger tests
Browse files Browse the repository at this point in the history
  • Loading branch information
@ankit-maverick
ankit-maverick committed Jun 6, 2013
1 parent e1c23ac commit a88ae64
Showing 1 changed file with 96 additions and 43 deletions.
139 changes: 96 additions & 43 deletions skimage/exposure/tests/test_exposure.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

import numpy as np
from numpy.testing import assert_array_almost_equal as assert_close
from numpy.testing import assert_array_equal
import skimage
from skimage import data
from skimage import exposure
Expand Down Expand Up @@ -184,8 +185,7 @@ def test_rescale_intensity_gamma_one():
"""Same image should be returned for gamma equal to one"""
image = data.camera()
result = exposure.rescale_intensity_gamma(image, 1)
assert result.mean() == image.mean()
assert result.std() == image.std()
assert_array_equal(result, image)


def test_rescale_intensity_gamma_zero():
Expand All @@ -198,72 +198,125 @@ def test_rescale_intensity_gamma_zero():


def test_rescale_intensity_gamma_less_one():
"""Output's mean should be greater than input's mean for gamma less than
one"""
image = data.camera()
"""Verifying the output with expected results for gamma
correction with gamma equal to half"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 0, 31, 45, 55, 63, 71, 78, 84],
[ 90, 95, 100, 105, 110, 115, 119, 123],
[127, 131, 135, 139, 142, 146, 149, 153],
[156, 159, 162, 165, 168, 171, 174, 177],
[180, 183, 186, 188, 191, 194, 196, 199],
[201, 204, 206, 209, 211, 214, 216, 218],
[221, 223, 225, 228, 230, 232, 234, 236],
[238, 241, 243, 245, 247, 249, 251, 253]], dtype=np.uint8)

result = exposure.rescale_intensity_gamma(image, 0.5)
assert result.mean() > image.mean()
assert_array_equal(result, expected)


def test_rescale_intensity_gamma_greater_one():
"""Output's mean should be less than input's mean for gamma greater than
one"""
image = data.camera()
"""Verifying the output with expected results for gamma
correction with gamma equal to two"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 0, 0, 0, 0, 1, 1, 2, 3],
[ 4, 5, 6, 7, 9, 10, 12, 14],
[ 16, 18, 20, 22, 25, 27, 30, 33],
[ 36, 39, 42, 45, 49, 52, 56, 60],
[ 64, 68, 72, 76, 81, 85, 90, 95],
[100, 105, 110, 116, 121, 127, 132, 138],
[144, 150, 156, 163, 169, 176, 182, 189],
[196, 203, 211, 218, 225, 233, 241, 249]], dtype=np.uint8)

result = exposure.rescale_intensity_gamma(image, 2)
assert result.mean() < image.mean()
assert_array_equal(result, expected)


# Test Logarithmic Correction
# ===========================

def test_rescale_intensity_logarithmic():
"""Output's mean should be greater than input's mean and all pixel values
in output should be either greater than or equal to that of corresponding
pixel in input for logarithmiccorrection with multiplier constant equal
to unity"""
image = data.camera()
"""Verifying the output with expected results for logarithmic
correction with multiplier constant multiplier equal to unity"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 0, 5, 11, 16, 22, 27, 33, 38],
[ 43, 48, 53, 58, 63, 68, 73, 77],
[ 82, 86, 91, 95, 100, 104, 109, 113],
[117, 121, 125, 129, 133, 137, 141, 145],
[149, 153, 157, 160, 164, 168, 172, 175],
[179, 182, 186, 189, 193, 196, 199, 203],
[206, 209, 213, 216, 219, 222, 225, 228],
[231, 234, 238, 241, 244, 246, 249, 252]], dtype=np.uint8)

result = exposure.rescale_intensity_logarithmic(image, 1)
assert result.mean() > image.mean()
assert result.all() >= image.all()
assert_array_equal(result, expected)


def test_rescale_intensity_inv_logarithmic():
"""Output's mean should be less than input's mean and all pixel values
in output should be either less than or equal to that of corresponding
pixel in inputfor inverse logarithmic correction with multiplier constant
equal to unity"""
image = data.camera()
"""Verifying the output with expected results for inverse logarithmic
correction with multiplier constant multiplier equal to unity"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 0, 2, 5, 8, 11, 14, 17, 20],
[ 23, 26, 29, 32, 35, 38, 41, 45],
[ 48, 51, 55, 58, 61, 65, 68, 72],
[ 76, 79, 83, 87, 90, 94, 98, 102],
[106, 110, 114, 118, 122, 126, 130, 134],
[138, 143, 147, 151, 156, 160, 165, 170],
[174, 179, 184, 188, 193, 198, 203, 208],
[213, 218, 224, 229, 234, 239, 245, 250]], dtype=np.uint8)

result = exposure.rescale_intensity_logarithmic(image, 1, -1)
assert result.mean() < image.mean()
assert result.all() <= image.all()
assert_array_equal(result, expected)


# Test Sigmoid Correction
# =======================

def test_rescale_intensity_sigmoid_cutoff_one():
"""Output's std should be less than input's std and all pixel values
in output should be either less than or equal to that of
corresponding pixel in input for sigmoid correction with cutoff equal
to one and gain of 10"""
image = data.camera()
result = exposure.rescale_intensity_sigmoid(image, 1, 10)
assert result.std() < image.std()
assert result.all() <= image.all()
"""Verifying the output with expected results for sigmoid correction
with cutoff equal to one and gain of 5"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 1, 1, 1, 2, 2, 2, 2, 2],
[ 3, 3, 3, 4, 4, 4, 5, 5],
[ 5, 6, 6, 7, 7, 8, 9, 10],
[ 10, 11, 12, 13, 14, 15, 16, 18],
[ 19, 20, 22, 24, 25, 27, 29, 32],
[ 34, 36, 39, 41, 44, 47, 50, 54],
[ 57, 61, 64, 68, 72, 76, 80, 85],
[ 89, 94, 99, 104, 108, 113, 118, 123]], dtype=np.uint8)

result = exposure.rescale_intensity_sigmoid(image, 1, 5)
assert_array_equal(result, expected)


def test_rescale_intensity_sigmoid_cutoff_zero():
"""Output's std should be less than input's std and all pixel values
in output should be either greater than or equal to that of
corresponding pixel in input for sigmoid correction with cutoff equal
to zero and gain of 10"""
image = data.camera()
"""Verifying the output with expected results for sigmoid correction
with cutoff equal to zero and gain of 10"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[127, 137, 147, 156, 166, 175, 183, 191],
[198, 205, 211, 216, 221, 225, 229, 232],
[235, 238, 240, 242, 244, 245, 247, 248],
[249, 250, 250, 251, 251, 252, 252, 253],
[253, 253, 253, 253, 254, 254, 254, 254],
[254, 254, 254, 254, 254, 254, 254, 254],
[254, 254, 254, 254, 254, 254, 254, 254],
[254, 254, 254, 254, 254, 254, 254, 254]], dtype=np.uint8)

result = exposure.rescale_intensity_sigmoid(image, 0, 10)
assert result.std() < image.std()
assert result.all() >= image.all()
assert_array_equal(result, expected)


def test_rescale_intensity_sigmoid_cutoff_half():
"""Output's std should be greater than input's std for sigmoid
correction with cutoff equal to 0.5 and gain of 10"""
image = data.camera()
"""Verifying the output with expected results for sigmoid correction
with cutoff equal to half and gain of 10"""
image = np.uint8(4 * np.arange(64).reshape(8,8))
expected = np.array([[ 1, 1, 2, 2, 3, 3, 4, 5],
[ 5, 6, 7, 9, 10, 12, 14, 16],
[ 19, 22, 25, 29, 34, 39, 44, 50],
[ 57, 64, 72, 80, 89, 99, 108, 118],
[128, 138, 148, 158, 167, 176, 184, 192],
[199, 205, 211, 217, 221, 226, 229, 233],
[236, 238, 240, 242, 244, 246, 247, 248],
[249, 250, 250, 251, 251, 252, 252, 253]], dtype=np.uint8)

result = exposure.rescale_intensity_sigmoid(image, 0.5, 10)
assert result.std() > image.std()
assert_array_equal(result, expected)

0 comments on commit a88ae64

Please sign in to comment.