magni.imaging.measurements._random_line module¶
Module providing public functions for the magni.imaging.measurements subpackage.
Routine listings¶
 random_line_sample_image(h, w, scan_length, num_points, discrete=None,
 seed=None) Function for random line sampling an image.
 random_line_sample_surface(l, w, speed, sample_rate, time, discrete=None,
 seed=None) Function for random line sampling a surface.

magni.imaging.measurements._random_line.
random_line_sample_image
(h, w, scan_length, num_points, discrete=None, seed=None)[source]¶ Sample an image using a set of random straight lines.
The coordinates (in units of pixels) resulting from sampling an image of size h times w using a pattern based on a set of random straight lines are determined. The scan_length determines the length of the path scanned whereas num_points indicates the number of samples taken on that path. If discrete is set, it specifies the finite number of equally spaced lines from which the scan lines are be chosen at random. For reproducible results, the seed may be used to specify a fixed seed of the random number generator.
Parameters:  h (int) – The height of the area to scan in units of pixels.
 w (int) – The width of the area to scan in units of pixels.
 scan_length (float) – The length of the path to scan in units of pixels.
 num_points (int) – The number of samples to take on the scanned path.
 discrete (int or None, optional) – The number of equally spaced lines from which the scan lines are chosen (the default is None, which implies that no discritisation is used).
 seed (int or None, optional) – The seed used for the random number generator (the defaul is None, which implies that the random number generator is not seeded).
Returns: coords (ndarray) – The coordinates of the samples arranged into a 2D array, such that each row is a coordinate pair (x, y).
Notes
The orientation of the coordinate system is such that the width w is measured along the xaxis whereas the height h is measured along the yaxis.
Each of the scanned lines span the entire width of the image with the exception of the last line that may only be partially scanned if the scan_length implies this. The top and bottom lines of the image are always included in the scan.
Examples
For example,
>>> import numpy as np >>> from magni.imaging.measurements import random_line_sample_image >>> h = 10 >>> w = 10 >>> scan_length = 50.0 >>> num_points = 12 >>> seed = 6021 >>> np.set_printoptions(suppress=True) >>> random_line_sample_image(h, w, scan_length, num_points, seed=seed) array([[ 0.5 , 0.5 ], [ 4.59090909, 0.5 ], [ 8.68181818, 0.5 ], [ 7.01473938, 1.28746666], [ 2.92383029, 1.28746666], [ 0.5 , 2.95454545], [ 0.5 , 7.04545455], [ 4.03665944, 7.59970419], [ 8.12756853, 7.59970419], [ 8.68181818, 9.5 ], [ 4.59090909, 9.5 ], [ 0.5 , 9.5 ]])

magni.imaging.measurements._random_line.
random_line_sample_surface
(l, w, speed, sample_rate, time, discrete=None, seed=None)[source]¶ Sample a surface area using a set of random straight lines.
The coordinates (in units of meters) resulting from sampling an image of size l times w using a pattern based on a set of random straight lines are determined. The scanned path is determined from the probe speed and the scan
time
. If discrete is set, it specifies the finite number of equally spaced lines from which the scan lines are be chosen at random. For reproducible results, the seed may be used to specify a fixed seed of the random number generator.Parameters:  l (float) – The length of the area to scan in units of meters.
 w (float) – The width of the area to scan in units of meters.
 speed (float) – The probe speed in units of meters/second.
 sample_rate (float) – The sample rate in units of Hertz.
 time (float) – The scan time in units of seconds.
 discrete (int or None, optional) – The number of equally spaced lines from which the scan lines are chosen (the default is None, which implies that no discritisation is used).
 seed (int or None, optional) – The seed used for the random number generator (the defaul is None, which implies that the random number generator is not seeded).
Returns: coords (ndarray) – The coordinates of the samples arranged into a 2D array, such that each row is a coordinate pair (x, y).
Notes
The orientation of the coordinate system is such that the width w is measured along the xaxis whereas the length l is measured along the yaxis.
Each of the scanned lines span the entire width of the image with the exception of the last line that may only be partially scanned if the speed and
time
implies this. The top and bottom lines of the image are always included in the scan and are not included in the discrete number of lines.Examples
For example,
>>> import numpy as np >>> from magni.imaging.measurements import random_line_sample_surface >>> l = 2e6 >>> w = 2e6 >>> speed = 7e7 >>> sample_rate = 1.0 >>> time = 12.0 >>> seed = 6021 >>> np.set_printoptions(suppress=True) >>> random_line_sample_surface(l, w, speed, sample_rate, time, seed=seed) array([[ 0. , 0. ], [ 0.00000067, 0. ], [ 0.00000133, 0. ], [ 0.000002 , 0. ], [ 0.000002 , 0.00000067], [ 0.000002 , 0.00000133], [ 0.00000158, 0.00000158], [ 0.00000091, 0.00000158], [ 0.00000024, 0.00000158], [ 0. , 0.000002 ], [ 0.00000067, 0.000002 ], [ 0.00000133, 0.000002 ], [ 0.000002 , 0.000002 ]])