tra-analysis/analysis-master/tra_analysis/fits.py
Dev Singh c48c512cf6
Implement fitting to circle using LSC and HyperFit (#45)
* chore: add pylint to devcontainer

Signed-off-by: Dev Singh <dev@devksingh.com>

* feat: init LSC fitting

cuda and cpu-based LSC fitting using cupy and numpy

Signed-off-by: Dev Singh <dev@devksingh.com>

* docs: add changelog entry and module to class list

Signed-off-by: Dev Singh <dev@devksingh.com>

* docs: fix typo in comment

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: only import cupy if cuda available

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: move to own file, abandon cupy

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: remove numba dep

Signed-off-by: Dev Singh <dev@devksingh.com>

* deps: remove cupy dep

Signed-off-by: Dev Singh <dev@devksingh.com>

* feat: add tests

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: correct indentation

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: variable names

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: add self when refering to coords

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: numpy ordering

Signed-off-by: Dev Singh <dev@devksingh.com>

* docs: remove version bump, nomaintain

add notice that module is not actively maintained, may be removed in future release

Signed-off-by: Dev Singh <dev@devksingh.com>

* fix: remove hyperfit as not being impled

Signed-off-by: Dev Singh <dev@devksingh.com>
2020-09-24 21:06:30 -05:00

85 lines
2.4 KiB
Python

# Titan Robotics Team 2022: CPU fitting models
# Written by Dev Singh
# Notes:
# this module is cuda-optimized (as appropriate) and vectorized (except for one small part)
# setup:
__version__ = "0.0.1"
# changelog should be viewed using print(analysis.fits.__changelog__)
__changelog__ = """changelog:
0.0.1:
- initial release, add circle fitting with LSC
"""
__author__ = (
"Dev Singh <dev@devksingh.com>"
)
__all__ = [
'CircleFit'
]
import numpy as np
class CircleFit:
"""Class to fit data to a circle using the Least Square Circle (LSC) method"""
# For more information on the LSC method, see:
# http://www.dtcenter.org/sites/default/files/community-code/met/docs/write-ups/circle_fit.pdf
def __init__(self, x, y, xy=None):
self.ournp = np #todo: implement cupy correctly
if type(x) == list:
x = np.array(x)
if type(y) == list:
y = np.array(y)
if type(xy) == list:
xy = np.array(xy)
if xy != None:
self.coords = xy
else:
# following block combines x and y into one array if not already done
self.coords = self.ournp.vstack(([x.T], [y.T])).T
def calc_R(x, y, xc, yc):
"""Returns distance between center and point"""
return self.ournp.sqrt((x-xc)**2 + (y-yc)**2)
def f(c, x, y):
"""Returns distance between point and circle at c"""
Ri = calc_R(x, y, *c)
return Ri - Ri.mean()
def LSC(self):
"""Fits given data to a circle and returns the center, radius, and variance"""
x = self.coords[:, 0]
y = self.coords[:, 1]
# guessing at a center
x_m = self.ournp.mean(x)
y_m = self.ournp.mean(y)
# calculation of the reduced coordinates
u = x - x_m
v = y - y_m
# linear system defining the center (uc, vc) in reduced coordinates:
# Suu * uc + Suv * vc = (Suuu + Suvv)/2
# Suv * uc + Svv * vc = (Suuv + Svvv)/2
Suv = self.ournp.sum(u*v)
Suu = self.ournp.sum(u**2)
Svv = self.ournp.sum(v**2)
Suuv = self.ournp.sum(u**2 * v)
Suvv = self.ournp.sum(u * v**2)
Suuu = self.ournp.sum(u**3)
Svvv = self.ournp.sum(v**3)
# Solving the linear system
A = self.ournp.array([ [ Suu, Suv ], [Suv, Svv]])
B = self.ournp.array([ Suuu + Suvv, Svvv + Suuv ])/2.0
uc, vc = self.ournp.linalg.solve(A, B)
xc_1 = x_m + uc
yc_1 = y_m + vc
# Calculate the distances from center (xc_1, yc_1)
Ri_1 = self.ournp.sqrt((x-xc_1)**2 + (y-yc_1)**2)
R_1 = self.ournp.mean(Ri_1)
# calculate residual error
residu_1 = self.ournp.sum((Ri_1-R_1)**2)
return (xc_1, yc_1, R_1, residu_1)