predictor.py

from .. import utils as U
from ..imports import *
from ..predictor import Predictor
from .preprocessor import ImagePreprocessor


class ImagePredictor(Predictor):
    """
    ```
    predicts image classes
    ```
    """

    def __init__(self, model, preproc, batch_size=U.DEFAULT_BS):

        if not isinstance(model, keras.Model):
            raise ValueError("model must be of instance keras.Model")
        if not isinstance(preproc, ImagePreprocessor):
            raise ValueError("preproc must be instance of ImagePreprocessor")
        self.model = model
        self.preproc = preproc
        self.datagen = self.preproc.get_preprocessor()
        self.c = self.preproc.get_classes()
        self.batch_size = batch_size

    def get_classes(self):
        return self.c

    def explain(self, img_fpath):
        """
        ```
        Highlights image to explain prediction
        ```
        """
        # if U.is_tf_keras():
        # warnings.warn("currently_unsupported: explain() method is not available because tf.keras is "+\
        # "not yet adequately supported by the eli5 library. You can switch to " +\
        # "stand-alone Keras by setting os.environ['TF_KERAS']='0'" )
        # return

        try:
            import eli5
        except:
            msg = (
                "ktrain requires a forked version of eli5 to support tf.keras. "
                + "Install with: pip install https://github.com/amaiya/eli5/archive/refs/heads/tfkeras_0_10_1.zip"
            )
            warnings.warn(msg)
            return

        # if not hasattr(eli5, 'KTRAIN'):
        if (
            not hasattr(eli5, "KTRAIN_ELI5_TAG")
            or eli5.KTRAIN_ELI5_TAG != KTRAIN_ELI5_TAG
        ):
            warnings.warn(
                "Since eli5 does not yet support tf.keras, ktrain uses a forked version of eli5.  "
                + "We do not detect this forked version (or it is out-of-date), so predictor.explain may not work.  "
                + "It will work if you uninstall the current version of eli5 and install "
                + "the forked version:  "
                + "pip install https://github.com/amaiya/eli5/archive/refs/heads/tfkeras_0_10_1.zip"
            )
            return

        if not DISABLE_V2_BEHAVIOR:
            warnings.warn(
                "Please add os.environ['DISABLE_V2_BEHAVIOR'] = '1' at top of your script or notebook."
            )
            msg = (
                "\nFor image classification, the explain method currently requires disabling V2 behavior in TensorFlow 2.\n"
                + "Please add the following to the top of your script or notebook BEFORE you import ktrain and restart Colab runtime or Jupyter kernel:\n\n"
                + "import os\n"
                + "os.environ['DISABLE_V2_BEHAVIOR'] = '1'\n"
            )
            print(msg)
            return

        img = keras.preprocessing.image.load_img(
            img_fpath,
            target_size=self.preproc.target_size,
            color_mode=self.preproc.color_mode,
        )
        x = keras.preprocessing.image.img_to_array(img)
        x = np.expand_dims(x, axis=0)
        return eli5.show_prediction(self.model, x)

    def predict(self, data, return_proba=False):
        """
        ```
        Predicts class from image in array format.
        If return_proba is True, returns probabilities of each class.
        ```
        """
        if not isinstance(data, np.ndarray):
            raise ValueError("data must be numpy.ndarray")
        (generator, steps) = self.preproc.preprocess(data, batch_size=self.batch_size)
        return self.predict_generator(generator, steps=steps, return_proba=return_proba)

    def predict_filename(self, img_path, return_proba=False):
        """
        ```
        Predicts class from filepath to single image file.
        If return_proba is True, returns probabilities of each class.
        ```
        """
        if not os.path.isfile(img_path):
            raise ValueError("img_path must be valid file")
        (generator, steps) = self.preproc.preprocess(
            img_path, batch_size=self.batch_size
        )
        return self.predict_generator(generator, steps=steps, return_proba=return_proba)

    def predict_folder(self, folder, return_proba=False):
        """
        ```
        Predicts the classes of all images in a folder.
        If return_proba is True, returns probabilities of each class.
        ```

        """
        if not os.path.isdir(folder):
            raise ValueError("folder must be valid directory")
        (generator, steps) = self.preproc.preprocess(folder, batch_size=self.batch_size)
        result = self.predict_generator(
            generator, steps=steps, return_proba=return_proba
        )
        if len(result) != len(generator.filenames):
            raise Exception("number of results does not equal number of filenames")
        return list(zip(generator.filenames, result))

    def predict_generator(self, generator, steps=None, return_proba=False):
        # loss = self.model.loss
        # if callable(loss): loss = loss.__name__
        # treat_multilabel = False
        # if loss != 'categorical_crossentropy' and not return_proba:
        #    return_proba=True
        #    treat_multilabel = True
        classification, multilabel = U.is_classifier(self.model)
        if not classification:
            return_proba = True
        # *_generator methods are deprecated from TF 2.1.0
        # preds =  self.model.predict_generator(generator, steps=steps)
        preds = self.model.predict(generator, steps=steps)
        result = (
            preds
            if return_proba or multilabel
            else [self.c[np.argmax(pred)] for pred in preds]
        )
        if multilabel and not return_proba:
            return [list(zip(self.c, r)) for r in result]
        if not classification:
            return np.squeeze(result, axis=1)
        else:
            return result

    def predict_proba(self, data):
        return self.predict(data, return_proba=True)

    def predict_proba_folder(self, folder):
        return self.predict_folder(folder, return_proba=True)

    def predict_proba_filename(self, img_path):
        return self.predict_filename(img_path, return_proba=True)

    def predict_proba_generator(self, generator, steps=None):
        return self.predict_proba_generator(generator, steps=steps, return_proba=True)

    def analyze_valid(self, generator, print_report=True, multilabel=None):
        """
        ```
        Makes predictions on validation set and returns the confusion matrix.
        Accepts as input a genrator (e.g., DirectoryIterator, DataframeIterator)
        representing the validation set.


        Optionally prints a classification report.
        Currently, this method is only supported for binary and multiclass
        problems, not multilabel classification problems.
        ```
        """
        if multilabel is None:
            multilabel = U.is_multilabel(generator)
        if multilabel:
            warnings.warn("multilabel_confusion_matrix not yet supported - skipping")
            return

        y_true = generator.classes
        # *_generator methods are deprecated from TF 2.1.0
        # y_pred = self.model.predict_generator(generator)
        y_pred = self.model.predict(generator)
        y_pred = np.argmax(y_pred, axis=1)
        if print_report:
            print(classification_report(y_true, y_pred, target_names=self.c))
        if not multilabel:
            cm_func = confusion_matrix
            cm = cm_func(y_true, y_pred)
        else:
            cm = None
        return cm

    def _save_preproc(self, fpath):
        preproc_name = "tf_model.preproc"
        with open(os.path.join(fpath, preproc_name), "wb") as f:
            datagen = self.preproc.get_preprocessor()
            pfunc = datagen.preprocessing_function
            datagen.preprocessing_function = None
            pickle.dump(self.preproc, f)
            datagen.preprocessing_function = pfunc
        return