调整图像大小时出错：“错误：（-215：断言失败）func！= 0函数'resize'”

Question

我正在尝试通过将它们重新缩放到（10,10）来预先处理以numpy形状（33600,784）表示的图像数据集（mnist）和形状（28,28）的图像。我写了一个函数：

def resize_dataset(images):
    resized_images = []
    for img in images:
            img = img.reshape((28,28))
            resized_img = cv2.resize(img, dsize=(10, 10))
            resized_images.append(resized_img)
    return numpy.array(resized_images)

但是当我真的尝试重新缩放它们时

x_tr_resc = resize_dataset(x_tr)

我收到以下错误：

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-38-fc680e0206f0> in <module>()
----> 1 x_tr_resc = resize_dataset(x_tr)

<ipython-input-37-bd0b64255821> in resize_dataset(images)
      6     for img in images:
      7             img = img.reshape((28,28))
----> 8             resized_img = cv2.resize(img, dsize=(10, 10))
      9             resized_images.append(resized_img)
     10     return numpy.array(resized_images)

error: OpenCV(4.0.0) /io/opencv/modules/imgproc/src/resize.cpp:3662: error: (-215:Assertion failed) func != 0 in function 'resize'

我试图谷歌这个错误，但只发现在c ++上写相同错误的人做了非常不同的东西，比如这个：resize an image and changing its depth和这个：http://answers.opencv.org/question/19715/error-215-func-0-in-function-convertto/

我究竟做错了什么？

Answer 1

哦，我真的想通了。数据集中的图像为numpy.int64类型。我只需将图像转换为float32，就像这样：

def resize_dataset(images):
    resized_images = []
    for img in images:
            img = img.reshape((28,28)).astype('float32')  # <-- convert image to float32
            resized_img = cv2.resize(img, dsize=(10, 10))
            resized_images.append(resized_img)
    return numpy.array(resized_images)

现在它很好用。看起来cv2.resize无法使用int中表示的图像。希望这对任何人都有帮助