使用Matplotlib / Python绘制模糊的线条

Question

我想知道是否可以使用 Matplotlib 进行如下所示的可视化。

另一种观点：

来源：http://dl.acm.org/citation.cfm?id=1961832

这些图像的作用以及我想要做的是组合两个可视化。一个（背景）是一个简单的情节，可以用 imshow ， pcolor ， pcolormesh 完成，但另一个使用的纹理模糊的网格（ w 因子）决定了某些特征，在这种情况下，确定了不确定性。我不知道该怎么做是用不同的模糊绘制不同的线条。对于每个像素，我有一个不确定性，我应该在这个像素中画一条线，不确定性表示为线条模糊。

  

我不知道如何用 Matplotlib 来做后者（用模糊绘制线条）。

任何帮助将不胜感激。 先感谢您。

Answer 1

嗯，这就是我到目前为止所做的一切 - 我开始尝试复制fig. 2。

明天会更新。 （上半部分只是为了创建一些数据）

from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import proj3d
import numpy as np
import matplotlib.gridspec as gridspec
import matplotlib

def smooth1d(x, window_len):
    s=np.r_[2*x[0]-x[window_len:1:-1],x,2*x[-1]-x[-1:-window_len:-1]]
    w = np.hanning(window_len)
    y=np.convolve(w/w.sum(),s,mode='same')
    return y[window_len-1:-window_len+1]

def smooth2d(A, sigma=3):
    window_len = max(int(sigma), 3)*2+1
    A1 = np.array([smooth1d(x, window_len) for x in np.asarray(A)])
    A2 = np.transpose(A1)
    A3 = np.array([smooth1d(x, window_len) for x in A2])
    A4 = np.transpose(A3)

    return A4

class BaseFilter(object):
    def prepare_image(self, src_image, dpi, pad):
        ny, nx, depth = src_image.shape
        #tgt_image = np.zeros([pad*2+ny, pad*2+nx, depth], dtype="d")
        padded_src = np.zeros([pad*2+ny, pad*2+nx, depth], dtype="d")
        padded_src[pad:-pad, pad:-pad,:] = src_image[:,:,:]

        return padded_src#, tgt_image

    def get_pad(self, dpi):
        return 0

    def __call__(self, im, dpi):
        pad = self.get_pad(dpi)
        padded_src = self.prepare_image(im, dpi, pad)
        tgt_image = self.process_image(padded_src, dpi)
        return tgt_image, -pad, -pad

class GaussianFilter(BaseFilter):
    "simple gauss filter"
    def __init__(self, sigma, alpha=0.5, color=None):
        self.sigma = sigma
        self.alpha = alpha
        if color is None:
            self.color=(0, 0, 0)
        else:
            self.color=color

    def get_pad(self, dpi):
        return int(self.sigma*3/72.*dpi)


    def process_image(self, padded_src, dpi):
        #offsetx, offsety = int(self.offsets[0]), int(self.offsets[1])
        tgt_image = np.zeros_like(padded_src)
        aa = smooth2d(padded_src[:,:,-1]*self.alpha,
                      self.sigma/72.*dpi)
        tgt_image[:,:,-1] = aa
        tgt_image[:,:,:-1] = self.color
        return tgt_image


from matplotlib.artist import Artist

class FilteredArtistList(Artist):
    """
    A simple container to draw filtered artist.
    """
    def __init__(self, artist_list, filter):
        self._artist_list = artist_list
        self._filter = filter
        Artist.__init__(self)

    def draw(self, renderer):
        renderer.start_rasterizing()
        renderer.start_filter()
        for a in self._artist_list:
            a.draw(renderer)
        renderer.stop_filter(self._filter)
        renderer.stop_rasterizing()





##Create the landscape
from noise import snoise2

def boxOnSurface(rect, X,Y,Z):
  #Make rectangle of indicies to draw. Left the four loops expanded for clarity. Otherwise it's fairly ugly.
  rXs, rYs, rZs = [],[],[]

  for j in range(rect[0][1], rect[1][1]):
    i = rect[0][0]

    rXs.append(X[i][j])
    rYs.append(Y[i][j])
    rZs.append(Z[i][j])

  for i in range(rect[0][0], rect[1][0]):
    j = rect[1][1]

    rXs.append(X[i][j])
    rYs.append(Y[i][j])
    rZs.append(Z[i][j])

  for j in range(rect[1][1], rect[0][1], -1):
    i = rect[1][0]

    rXs.append(X[i][j])
    rYs.append(Y[i][j])
    rZs.append(Z[i][j])

  for i in range(rect[1][0], rect[0][0]-1, -1):
    j = rect[0][1]

    rXs.append(X[i][j])
    rYs.append(Y[i][j])
    rZs.append(Z[i][j])

  return rXs, rYs, rZs, [np.mean(rXs), np.mean(rYs), np.mean(rZs)]



octaves = 4
freq = octaves * 100


xs, ys = np.linspace(0.0, 100.0, 100), np.linspace(0.0, 100.0, 100)
X,Y = np.meshgrid(xs,ys)

Z1 = np.zeros(X.shape)


for i,x in enumerate(xs):
  for j,y in enumerate(ys):
    Z1[i][j] = int(snoise2(x/freq, y/freq, octaves) * 127.0 + 128.0)



# get some different colours for the surface.
faceValues = np.zeros(X.shape)

noise = []

for i,x in enumerate(xs):
  for j,y in enumerate(ys):
    faceValues[i][j] = snoise2(4*x/freq, 4*y/freq, octaves)

jet = cm.get_cmap("jet")
faceColours = []


for i,x in enumerate(xs):
  faceColours.append([])
  for j,y in enumerate(ys):
    normalised = (faceValues[i][j] - faceValues.min()) / (faceValues.max() - faceValues.min())
    faceColours[i].append(jet(normalised))
    faceValues[i][j] = normalised




fig = plt.figure()
miniPlotCount = 5
gs = gridspec.GridSpec(5, miniPlotCount)
ax = fig.add_subplot(gs[0:4,:], projection='3d')

miniAxes = []
for i in range(miniPlotCount):
  miniAxes.append(fig.add_subplot(gs[4,i]))

ax.plot_surface(X,Y,Z1, cmap=cm.jet, linewidth=0.2, cstride=2, rstride=2, facecolors=faceColours, vmin=0, vmax=1)


#This decides where we draw the rectangle to be inspecting.
rect = ((25,45),(65,70))

boxXs, boxYs, boxZs, middleOfBox = boxOnSurface(rect, X,Y,Z1)
ax.plot(boxXs, boxYs, boxZs)

xb, yb, zb = middleOfBox

xPoint, yPoint, _ = proj3d.proj_transform(xb, yb, zb, ax.get_proj())


labels = []
grids = []
for i in range(miniPlotCount):
  bbox = miniAxes[i].get_window_extent()
  xytext = ((bbox.min[0] + bbox.max[0])/2, (bbox.min[1] + bbox.max[1])/2)
  labels.append(ax.annotate("", xy=(xPoint,yPoint), arrowprops = {"arrowstyle":'->', "connectionstyle":'arc3,rad=0'}, textcoords="figure pixels", xytext=xytext))

#  miniAxes[i].contourf(X[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]], Y[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]], Z1[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]])#, vmin=Z1.min(), vmax=Z1.max())
  miniAxes[i].contourf(X[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]], Y[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]], faceValues[rect[0][0]:rect[1][0],rect[0][1]:rect[1][1]], vmin=faceValues.min(), vmax=faceValues.max())

# miniAxes[i].set_agg_filter(gaussFilter)
  gaussFilter = GaussianFilter(i)
  miniAxes[i].grid(linestyle="-", linewidth=2, agg_filter=gaussFilter)






def update_position(e):
    xPoint, yPoint, _ = proj3d.proj_transform(xb, yb, zb, ax.get_proj())
    for label in labels:
      label.xy = xPoint, yPoint
      label.update_positions(fig.canvas.renderer)
    fig.canvas.draw()

fig.canvas.mpl_connect('motion_notify_event', update_position)




plt.show()

创造了这个：

这模糊了网格线。 （我不确定为什么它没有模糊其中的两个）看来你可以通过添加agg_filter kwarg来设置你在matplotlib中获得的任何对象的agg_filter=。如果您编辑了GaussianFilter类，则可以将其设置为接收所有不确定性数据，然后使用它来对图像的各个部分应用模糊/不透明/无论什么。