Question

我想创建200个大小为（100 * 100）的图像帧，并将它们堆叠在最终大小为（200 * 100 * 100）的3-D数组中，其中x轴表示每个帧，即（1，100，100 ）应该是第一帧。

我无法将它们堆叠为3-D阵列。第一个循环通过堆叠前两帧创建了一个（2,100,100）数组，但此后不起作用，并导致了一个（2，）数组

import numpy as np
import random




def createCircle(width,height , rad ):
  w = random.randint(1, height)
  h = random.randint(1, height)
  center = [int(w), int(h)]
  radius = rad
  Y, X = np.ogrid[:height, :width]
  dist_from_center = np.sqrt((X - center[0])**2 + (Y-center[1])**2)
  mask = dist_from_center <= radius
  return mask


def addCircle(test_image):
  m = createCircle(width = 100, height = 100 , rad = 8 )
  masked_img = test_image.copy()
  masked_img[m] = 0
  return masked_img

img = np.zeros([100,100],dtype=np.uint8)
img.fill(20)
img_test = img  


def noise(image):
  row,col= image.shape
  mean = 0
  var = 0.1
  sigma = var**0.5
  gauss = np.random.normal(mean,sigma,(row,col))
  gauss = gauss.reshape(row,col)
  noisy = image + gauss #adding gauss noise
  s1 = np.sin(8)   #adding sin fill
  noisy += s1
  return noisy


#creates 1st frame
for i in range(4):
  im_first = addCircle(test_image=img_test)
  im_first = noise(im_first)



for i in range(200):
  for j in range(4):
    img_test = addCircle(test_image=img_test)
  im1 = noise(img_test)
  img_test = img
  im_first = np.array([im_first, im1])#stacks every new frame   (im1)#error in this

我需要一个（200,100,100）

Answer 1

您可以使用numpy.stack进行此操作。看看我的例子

import numpy as np

a = np.array([[1,2],[3,4]])
b = np.array([[10,11],[12,13]])
c = np.stack((a,b))
print(c.shape) #prints (2,2,2)
print(c[0])
print(c[1])

第二张打印输出

[[1 2]
 [3 4]]

第三次打印的输出

[[10 11]
 [12 13]]

请注意，您必须将tuple个2D数组而不是单个2D数组馈入numpy.stack

Answer 2

您可以初始化一个数组，然后用图像填充它。这往往比连续堆叠更有效率。

ims = np.zeros((200, 100, 100)) # initialize your array
for i in range(200):
  for j in range(4):
    img_test = addCircle(test_image=img_test)
  im1 = noise(img_test)
  ims[i, ...] = im1 # add the image to our initialized array

Answer 3

一种方法是创建要堆叠并使用arrays = [np.random.randn(100, 100) for _ in range(200)] #each matrix is of shape (100,100) stacked_array = np.stack(arrays, axis=0) #stacked_array.shape is (200,100,100)的二维矩阵的列表。

示例

{{1}}

将200个大小为（100 * 100）的2-d numpy数组堆叠在3-d numpy数组（200 * 100 * 100）中

3 个答案: