sphere_map.py

# Image Projection onto Sphere
# https://en.wikipedia.org/wiki/Equirectangular_projection
# Download the test image from the Wikipedia page!
# FB36 - 20160731
import math, random
from PIL import Image
import numpy as np
import serial
import serial.tools.list_ports
import sys
import glob
import serial
import time

ser = serial.Serial(
    port="/dev/ttyUSB0",
    baudrate=500000
)
if ser.isOpen():
    ser.close()
ser.open()
ser.isOpen()
ser.write('2\n')

imgxOutput = 768; imgyOutput = 768
pi2 = math.pi * 2
# 3D Sphere Rotation Angles (arbitrary)
# xy = -pi2 * random.random()
# xz = -pi2 * random.random()
# yz = -pi2 * random.random()
xy = 0
xz = 0
yz = 100.0 * np.pi/180.0
sxy = math.sin(xy); cxy = math.cos(xy)
sxz = math.sin(xz); cxz = math.cos(xz)
syz = math.sin(yz); cyz = math.cos(yz)
imageInput = Image.open("beer.png")
(imgxInput, imgyInput) = imageInput.size
pixelsInput = imageInput.load()
imageOutput = Image.new("RGB", (imgxOutput, imgyOutput))
pixelsOutput = imageOutput.load()
# define a sphere behind the screen
xc = (imgxOutput - 1.0) / 2
yc = (imgyOutput - 1.0) / 2
zc = min((imgxOutput - 1.0), (imgyOutput - 1.0)) / 2
r = min((imgxOutput - 1.0), (imgyOutput - 1.0)) / 2
# define eye point
xo = (imgxOutput - 1.0) / 2
yo = (imgyOutput - 1.0) / 2
zo = -min((imgxOutput - 1.0), (imgyOutput - 1.0))
xoc = xo - xc
yoc = yo - yc
zoc = zo - zc
doc2 = xoc * xoc + yoc * yoc + zoc * zoc
while(True):
    for yi in range(imgyOutput):
        for xi in range(imgxOutput):
           xio = xi - xo
           yio = yi - yo
           zio = 0.0 - zo
           dio = math.sqrt(xio * xio + yio * yio + zio * zio)
           xl = xio / dio
           yl = yio / dio
           zl = zio / dio
           dot = xl * xoc + yl * yoc + zl * zoc
           val = dot * dot - doc2 + r * r
           if val >= 0: # if there is line-sphere intersection
               if val == 0: # 1 intersection point
                   d = -dot
               else: # 2 intersection points => choose the closest
                   d = min(-dot + math.sqrt(val), -dot - math.sqrt(val))
                   xd = xo + xl * d
                   yd = yo + yl * d
                   zd = zo + zl * d
                   x = (xd - xc) / r
                   y = (yd - yc) / r
                   z = (zd - zc) / r
                   x0=x*cxy-y*sxy;y=x*sxy+y*cxy;x=x0 # xy-plane rotation
                   x0=x*cxz-z*sxz;z=x*sxz+z*cxz;x=x0 # xz-plane rotation
                   y0=y*cyz-z*syz;z=y*syz+z*cyz;y=y0 # yz-plane rotation
                   lng = (math.atan2(y, x) + pi2) % pi2
                   lat = math.acos(z)
                   ix = int((imgxInput - 1) * lng / pi2 + 0.5)
                   iy = int((imgyInput - 1) * lat / math.pi + 0.5)
                   lng = lng*180/np.pi
                   lat = lat*180/np.pi
                   if pixelsInput[ix, iy][0]==0:
                       print("lon %d lat %d"%(int(lng),int(lat)))
                       if lng<15 or lng >345:
                           continue
                       setpoint = '0 ' + str(int(lng)) + ' \n'
                       ser.write(setpoint)
                       setpoint = '1 ' + str(int(lat)) + ' \n'
                       ser.write(setpoint)
                       time.sleep(0.001)
                       ser.write('2\n')
                   else:
                       ser.write('3\n')
                   try:
                       pixelsOutput[xi, yi] = pixelsInput[ix, iy]
                   except:
                       pass

imageOutput.save("/home/letrend/Pictures/World.png", "PNG")