magni.imaging.measurements._uniform_line module

Module providing public functions for the magni.imaging.measurements subpackage.

Routine listings

uniform_line_sample_image(h, w, scan_length, num_points)

Function for uniform line sampling an image.

uniform_line_sample_surface(l, w, speed, sample_rate, time)

Function for uniform line sampling a surface.

magni.imaging.measurements._uniform_line.uniform_line_sample_image(h, w, scan_length, num_points)

Sample an image using a set of uniformly distributed 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 uniformly distributed 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.

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.

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 x-axis whereas the height h is measured along the y-axis.

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 uniform_line_sample_image
>>> h = 10
>>> w = 10
>>> scan_length = 50.0
>>> num_points = 12
>>> np.set_printoptions(suppress=True)
>>> uniform_line_sample_image(h, w, scan_length, num_points)
array([[ 0.5       ,  0.5       ],
       [ 4.59090909,  0.5       ],
       [ 8.68181818,  0.5       ],
       [ 9.22727273,  3.5       ],
       [ 5.13636364,  3.5       ],
       [ 1.04545455,  3.5       ],
       [ 1.04545455,  6.5       ],
       [ 5.13636364,  6.5       ],
       [ 9.22727273,  6.5       ],
       [ 8.68181818,  9.5       ],
       [ 4.59090909,  9.5       ],
       [ 0.5       ,  9.5       ]])

magni.imaging.measurements._uniform_line.uniform_line_sample_surface(l, w, speed, sample_rate, time)

Sample aa surface area using a set of uniformly distributed straight lines.

The coordinates (in units of meters) resulting from sampling an area of size l times w using a pattern based on a set of uniformly distributed straight lines are determined. The scanned path is determined from the probe speed and the scan time.

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.

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 x-axis whereas the height l is measured along the y-axis.

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 uniform_line_sample_surface
>>> l = 2e-6
>>> w = 2e-6
>>> speed = 7e-7
>>> sample_rate = 1.0
>>> time = 12.0
>>> np.set_printoptions(suppress=True)
>>> uniform_line_sample_surface(l, w, speed, sample_rate, time)
array([[ 0.        ,  0.        ],
       [ 0.00000067,  0.        ],
       [ 0.00000133,  0.        ],
       [ 0.000002  ,  0.        ],
       [ 0.000002  ,  0.00000067],
       [ 0.00000167,  0.000001  ],
       [ 0.000001  ,  0.000001  ],
       [ 0.00000033,  0.000001  ],
       [ 0.        ,  0.00000133],
       [ 0.        ,  0.000002  ],
       [ 0.00000067,  0.000002  ],
       [ 0.00000133,  0.000002  ],
       [ 0.000002  ,  0.000002  ]])