我刚开始学习CNN和机器学习，正在尝试按照TensorFlow的图像分类教程进行学习。

现在，Google Colab的链接在这里可以找到这里。我已经按照TensorFlow的官方教程进行操作，并稍作修改，将模型保存为h5格式而不是tf格式，这样我就可以使用Keras的model.predict_classes方法。

现在，我已经训练了模型，并从保存的模型中重新加载了模型。但是，每当我尝试预测图像时，我总是会得到list index out of range错误，我是这样做的：

def predict():  image = tf.io.read_file('target.jpeg')  image = tf.image.decode_jpeg(image, channels=3)  image = tf.image.resize(image, [224, 224])  print(model.predict_classes(image)[0])

target.jpeg是我从flowers_photos数据集中取出的一张图片，该模型就是在这个数据集上训练的。

错误的回溯信息如下：

Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "<stdin>", line 7, in predict  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/sequential.py", line 319, in predict_classes    proba = self.predict(x, batch_size=batch_size, verbose=verbose)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training.py", line 821, in predict    use_multiprocessing=use_multiprocessing)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training_arrays.py", line 712, in predict    callbacks=callbacks)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training_arrays.py", line 187, in model_iteration    f = _make_execution_function(model, mode)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training_arrays.py", line 555, in _make_execution_function    return model._make_execution_function(mode)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training.py", line 2037, in _make_execution_function    self._make_predict_function()  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/engine/training.py", line 2027, in _make_predict_function    **kwargs)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/backend.py", line 3544, in function    return EagerExecutionFunction(inputs, outputs, updates=updates, name=name)  File "/home/amitjoki/.local/lib/python3.6/site-packages/tensorflow/python/keras/backend.py", line 3468, in __init__    self.outputs[0] = array_ops.identity(self.outputs[0])IndexError: list index out of range

我广泛搜索了但没有找到任何解决方案。如果有人能指导我如何解决这个问题，我将不胜感激。

回答：

Keras中的所有预测函数都期望输入一个批次。因此，由于您是在单张图像上进行预测，您需要在图像张量的开头添加一个轴来表示批次轴：

image = tf.expand_dims(image, axis=0)   # 形状将变为(1, 224, 224, 3)print(model.predict_classes(image)[0])