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# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (C) 2019, Raspberry Pi Ltd
#
# ctt_ransac.py - camera tuning tool RANSAC selector for Macbeth chart locator
import numpy as np
scale = 2
"""
constructs normalised macbeth chart corners for ransac algorithm
"""
def get_square_verts(c_err=0.05, scale=scale):
"""
define macbeth chart corners
"""
b_bord_x, b_bord_y = scale*8.5, scale*13
s_bord = 6*scale
side = 41*scale
x_max = side*6 + 5*s_bord + 2*b_bord_x
y_max = side*4 + 3*s_bord + 2*b_bord_y
c1 = (0, 0)
c2 = (0, y_max)
c3 = (x_max, y_max)
c4 = (x_max, 0)
mac_norm = np.array((c1, c2, c3, c4), np.float32)
mac_norm = np.array([mac_norm])
square_verts = []
square_0 = np.array(((0, 0), (0, side),
(side, side), (side, 0)), np.float32)
offset_0 = np.array((b_bord_x, b_bord_y), np.float32)
c_off = side * c_err
offset_cont = np.array(((c_off, c_off), (c_off, -c_off),
(-c_off, -c_off), (-c_off, c_off)), np.float32)
square_0 += offset_0
square_0 += offset_cont
"""
define macbeth square corners
"""
for i in range(6):
shift_i = np.array(((i*side, 0), (i*side, 0),
(i*side, 0), (i*side, 0)), np.float32)
shift_bord = np.array(((i*s_bord, 0), (i*s_bord, 0),
(i*s_bord, 0), (i*s_bord, 0)), np.float32)
square_i = square_0 + shift_i + shift_bord
for j in range(4):
shift_j = np.array(((0, j*side), (0, j*side),
(0, j*side), (0, j*side)), np.float32)
shift_bord = np.array(((0, j*s_bord),
(0, j*s_bord), (0, j*s_bord),
(0, j*s_bord)), np.float32)
square_j = square_i + shift_j + shift_bord
square_verts.append(square_j)
# print('square_verts')
# print(square_verts)
return np.array(square_verts, np.float32), mac_norm
def get_square_centres(c_err=0.05, scale=scale):
"""
define macbeth square centres
"""
verts, mac_norm = get_square_verts(c_err, scale=scale)
centres = np.mean(verts, axis=1)
# print('centres')
# print(centres)
return np.array(centres, np.float32)
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