Python - Numpy 3D 数组 - 连接问题

Question

我有一个包含 46 个条目的 txt 文件，如下所示 -

2020-05-24T10:57:12.743606#[0.0, 0.0, 0.0653934553265572, 0.0, 1.0, 0.0]
2020-05-24T10:57:12.806380#[0.0, 0.0, 0.0, 0.0, 1.0, 0.0]
2020-05-24T10:57:12.869022#[0.0, 0.0, 0.0, 0.0, 1.0, 0.0]

第一个参数是拍摄的相机图像的时间戳。对于每个时间戳，有 3 个 RGB 图像。

我的目标是沿着 channel 轴(轴 = 2)连接它们。图像尺寸为 70x320x3。所以所需的输出是 46x70x320x9。

我需要等到所有 3 个图像都被识别，然后将它们附加到列表并将其提供给 numpy 数组。我失败了，因为我得到的输出尺寸是 46x138(对于来自附加的 3 张图像)x70x320x3 46x138x70x320x3 在连接之前。当使用 axis =2 or 3

实现时，串联不起作用

我怎样才能得到 46x70x320x9？

代码-

with open("train.txt", 'r') as f:
    data = f.readlines()[:]
images = []
image_concat = []
labels = []
for row in data:
    for camera in ['center', 'left', 'right']:
        img_id, label = row.strip("\n").split("#")
        img_path = os.path.join(IMG_PATH, '{}-{}.jpg'.format(camera, img_id))
        image = cv2.imread(img_path)
        images.append(image)
        if camera == 'right':
            image_concat.append(images)

X_data = np.array(image_concat)
print(X_data.shape)

引用链接 -

Need help combining two 3 channel images into 6 channel image Python

numpy: concatenate two arrays along the 3rd dimension

numpy concatenate multiple arrays arrays

numpy concatenate over dimension

请帮忙。任何帮助将不胜感激。谢谢。

Answer 1

这是一个带有虚拟数据的实现

collect = []
for i in range(46):

    #create dummy arrays, simulate list of 3 RGB images
    a = [np.zeros((70,320,3)) for b in range(3)]
    # a[0].shape: (70,320,3) 

    #concatenate along axis 2
    b = np.concatenate(a, axis=2)
    # b.shape: (70,320,9)

    #create new axis in position zero
    b = b[np.newaxis, ...]
    # b.shape : (1,70,320,9)
    collect.append(b)

output = np.concatenate(collect, axis=0)

output.shape
(46, 70, 320, 9)

编辑:

# IIUC:
# left camera makes 70,320,3 at time t
# right camera makes 70,320,3 at time t
# center camera makes 70,320,3 at time t
# these need to be concatenated to 70,320,9
# if so, you can use a dictionary

#initialise dict
collected_images = {}
for timepoint, row in enumerate(data):
    #at every timepoint, initialise dict entry
    collected_images[timepoint] = []
    for camera in ['center', 'left', 'right']:
        image = cv2.imread('path/to/image')
        collected_images[timepoint].append(image)

# now you have all images in a dictionary
# to generate the array, you can

output = []
for key, val in collected_iamges.items():
    temp = np.concatenate(val, axis=2)
    output.append(temp[np.newaxis, ...])

output = np.concatenate(output, axis=0)