def central_scaled_coordinates(self):
return geometry_util.central_scaled_coordinate_2d_from(
shape_native=self.shape_native,
pixel_scales=self.pixel_scales,
origin=self.origin,
)
def grid_pixel_centres_2d_slim_from(
grid_scaled_2d_slim: np.ndarray,
shape_native: (int, int),
pixel_scales: (float, float),
origin: (float, float) = (0.0, 0.0),
) -> np.ndarray:
"""
Convert a slimmed grid of 2D (y,x) scaled coordinates to a slimmed grid of 2D (y,x) pixel values. Pixel coordinates
are returned as integers such that they map directly to the pixel they are contained within.
The input and output grids are both slimmed and therefore shape (total_pixels, 2).
The pixel coordinate origin is at the top left corner of the grid, such that the pixel [0,0] corresponds to
the highest (most positive) y scaled coordinate and lowest (most negative) x scaled coordinate on the gird.
The scaled coordinate grid is defined by the class attribute origin, and coordinates are shifted to this
origin before computing their 1D grid pixel indexes.
Parameters
----------
grid_scaled_2d_slim: np.ndarray
The slimmed grid of 2D (y,x) coordinates in scaled units which is converted to pixel indexes.
shape_native : (int, int)
The (y,x) shape of the original 2D array the scaled coordinates were computed on.
pixel_scales : (float, float)
The (y,x) scaled units to pixel units conversion factor of the original 2D array.
origin : (float, flloat)
The (y,x) origin of the grid, which the scaled grid is shifted
Returns
-------
ndarray
A slimmed grid of 2D (y,x) pixel indexes with dimensions (total_pixels, 2).
Examples
--------
grid_scaled_2d_slim = np.array([[1.0, 1.0], [2.0, 2.0], [3.0, 3.0], [4.0, 4.0]])
grid_pixels_2d_slim = grid_scaled_2d_slim_from(grid_scaled_2d_slim=grid_scaled_2d_slim, shape=(2,2),
pixel_scales=(0.5, 0.5), origin=(0.0, 0.0))
"""
grid_pixels_2d_slim = np.zeros((grid_scaled_2d_slim.shape[0], 2))
centres_scaled = geometry_util.central_scaled_coordinate_2d_from(
shape_native=shape_native, pixel_scales=pixel_scales, origin=origin)
for slim_index in range(grid_scaled_2d_slim.shape[0]):
grid_pixels_2d_slim[slim_index,
0] = int((-grid_scaled_2d_slim[slim_index, 0] /
pixel_scales[0]) + centres_scaled[0] +
0.5)
grid_pixels_2d_slim[slim_index,
1] = int((grid_scaled_2d_slim[slim_index, 1] /
pixel_scales[1]) + centres_scaled[1] +
0.5)
return grid_pixels_2d_slim
def grid_2d_slim_via_mask_from(
mask_2d: np.ndarray,
pixel_scales: (float, float),
sub_size: int,
origin: (float, float) = (0.0, 0.0),
) -> np.ndarray:
"""
For a sub-grid, every unmasked pixel of its 2D mask with shape (total_y_pixels, total_x_pixels) is divided into
a finer uniform grid of shape (total_y_pixels*sub_size, total_x_pixels*sub_size). This routine computes the (y,x)
scaled coordinates a the centre of every sub-pixel defined by this 2D mask array.
The sub-grid is returned on an array of shape (total_unmasked_pixels*sub_size**2, 2). y coordinates are
stored in the 0 index of the second dimension, x coordinates in the 1 index. Masked coordinates are therefore
removed and not included in the slimmed grid.
Grid2D are defined from the top-left corner, where the first unmasked sub-pixel corresponds to index 0.
Sub-pixels that are part of the same mask array pixel are indexed next to one another, such that the second
sub-pixel in the first pixel has index 1, its next sub-pixel has index 2, and so forth.
Parameters
----------
mask_2d : np.ndarray
A 2D array of bools, where `False` values are unmasked and therefore included as part of the calculated
sub-grid.
pixel_scales : (float, float)
The (y,x) scaled units to pixel units conversion factor of the 2D mask array.
sub_size : int
The size of the sub-grid that each pixel of the 2D mask array is divided into.
origin : (float, flloat)
The (y,x) origin of the 2D array, which the sub-grid is shifted around.
Returns
-------
ndarray
A slimmed sub grid of (y,x) scaled coordinates at the centre of every pixel unmasked pixel on the 2D mask
array. The sub grid array has dimensions (total_unmasked_pixels*sub_size**2, 2).
Examples
--------
mask = np.array([[True, False, True],
[False, False, False]
[True, False, True]])
grid_slim = grid_2d_slim_via_mask_from(mask=mask, pixel_scales=(0.5, 0.5), sub_size=1, origin=(0.0, 0.0))
"""
total_sub_pixels = mask_2d_util.total_sub_pixels_2d_from(mask_2d, sub_size)
grid_slim = np.zeros(shape=(total_sub_pixels, 2))
centres_scaled = geometry_util.central_scaled_coordinate_2d_from(
shape_native=mask_2d.shape, pixel_scales=pixel_scales, origin=origin)
sub_index = 0
y_sub_half = pixel_scales[0] / 2
y_sub_step = pixel_scales[0] / (sub_size)
x_sub_half = pixel_scales[1] / 2
x_sub_step = pixel_scales[1] / (sub_size)
for y in range(mask_2d.shape[0]):
for x in range(mask_2d.shape[1]):
if not mask_2d[y, x]:
y_scaled = (y - centres_scaled[0]) * pixel_scales[0]
x_scaled = (x - centres_scaled[1]) * pixel_scales[1]
for y1 in range(sub_size):
for x1 in range(sub_size):
grid_slim[sub_index,
0] = -(y_scaled - y_sub_half +
y1 * y_sub_step + (y_sub_step / 2.0))
grid_slim[sub_index,
1] = (x_scaled - x_sub_half +
x1 * x_sub_step + (x_sub_step / 2.0))
sub_index += 1
return grid_slim