ai.djl.training.evaluator.SingleShotDetectionAccuracy Maven / Gradle / Ivy
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/*
* Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
* with the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0/
*
* or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
* OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
* and limitations under the License.
*/
package ai.djl.training.evaluator;
import ai.djl.modality.cv.MultiBoxTarget;
import ai.djl.ndarray.NDArray;
import ai.djl.ndarray.NDList;
import ai.djl.ndarray.types.DataType;
import ai.djl.util.Pair;
/**
* {@code SingleShotDetectionAccuracy} is an implementation of {@link AbstractAccuracy}. It is used
* while training a Single Shot Detection (SSD) model for object detection. It uses the targets
* computed by {@link MultiBoxTarget}, and computes the class prediction accuracy against the
* computed targets.
*/
public class SingleShotDetectionAccuracy extends AbstractAccuracy {
private MultiBoxTarget multiBoxTarget = MultiBoxTarget.builder().build();
/**
* Creates a new instance of {@link SingleShotDetectionAccuracy} with the given name.
*
* @param name the name given to the accuracy
*/
public SingleShotDetectionAccuracy(String name) {
super(name, 0);
}
/** {@inheritDoc} */
@Override
protected Pair accuracyHelper(NDList labels, NDList predictions) {
NDArray anchors = predictions.get(0);
NDArray classPredictions = predictions.get(1);
NDList targets =
multiBoxTarget.target(
new NDList(anchors, labels.head(), classPredictions.transpose(0, 2, 1)));
NDArray classLabels = targets.get(2);
checkLabelShapes(classLabels, classPredictions);
NDArray predictionReduced = classPredictions.argMax(-1);
long total = classLabels.size();
NDArray numCorrect =
classLabels.toType(DataType.INT64, false).eq(predictionReduced).countNonzero();
return new Pair<>(total, numCorrect);
}
}