PseudoAugment Learning to Use Unlabeled Data for Data Augmentation in Point Clouds Zhaoqi Leng1 Shuyang Cheng1 Benjamin Caine2 Weiyue Wang1 Xiao

2025-05-02 0 0 4.92MB 19 页 10玖币
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PseudoAugment: Learning to Use Unlabeled
Data for Data Augmentation in Point Clouds
Zhaoqi Leng1, Shuyang Cheng1, Benjamin Caine2, Weiyue Wang1, Xiao
Zhang1, Jonathon Shlens2, Mingxing Tan1, and Dragomir Anguelov1
Waymo1, Google2
1{lengzhaoqi, weiyuewang, tanmingxing, dragomir}@waymo.com
Abstract. Data augmentation is an important technique to improve
data efficiency and save labeling cost for 3D detection in point clouds.
Yet, existing augmentation policies have so far been designed to only
utilize labeled data, which limits the data diversity. In this paper, we
recognize that pseudo labeling and data augmentation are complemen-
tary, thus propose to leverage unlabeled data for data augmentation to
enrich the training data. In particular, we design three novel pseudo-
label based data augmentation policies (PseudoAugments) to fuse both
labeled and pseudo-labeled scenes, including frames (PseudoFrame), ob-
jects (PseudoBBox), and background (PseudoBackground). PseudoAug-
ments outperforms pseudo labeling by mitigating pseudo labeling er-
rors and generating diverse fused training scenes. We demonstrate Pseu-
doAugments generalize across point-based and voxel-based architectures,
different model capacity and both KITTI and Waymo Open Dataset. To
alleviate the cost of hyperparameter tuning and iterative pseudo label-
ing, we develop a population-based data augmentation framework for 3D
detection, named AutoPseudoAugment. Unlike previous works that per-
form pseudo-labeling offline, our framework performs PseudoAugments
and hyperparameter tuning in one shot to reduce computational cost.
Experimental results on the large-scale Waymo Open Dataset show our
method outperforms state-of-the-art auto data augmentation method
(PPBA) and self-training method (pseudo labeling). In particular, Au-
toPseudoAugment is about 3×and 2×data efficient on vehicle and
pedestrian tasks compared to prior arts. Notably, AutoPseudoAugment
nearly matches the full dataset training results, with just 10% of the
labeled run segments on the vehicle detection task.
Keywords: data augmentation, semi-supervised learning, 3D detection.
1 Introduction
3D object detection from LiDAR point cloud data is a core component of au-
tonomous driving. Building accurate 3D object detection systems requires vast
quantities of labeled scenes with accurate 3D bounding box annotations. While
unlabeled LiDAR data is readily available, labeling itself is costly, e.g., 6.4 hours
of LiDAR data contains more than 10 million human labeled 3D boxes [58].
arXiv:2210.13428v1 [cs.CV] 24 Oct 2022
2 Z. Leng et al.
Fig. 1: AutoPseudoAugment is more data efficient than auto data aug-
mentation and self-training methods. Data augmentation only (PPBA [8]),
self-training (Pseudo labeling [4]) and our method (AutoPseudoAugment) are
evaluated using 3D detection AP at Level 1 difficulty on the validation split of
the Waymo Open Dataset [58]. Using 10% of labeled run segments, AutoPseu-
doAugment is about 3×data efficient as PPBA and Pseudo label method on the
vehicle class and 2×on the pedestrian class. AutoPseudoAugment is nearly 10×
and more than 5×data efficient compared to the supervised (no augmentation)
vehicle and pedestrian baselines.
Thus, an effective way to increase the data efficiency for model training would
be very appealing.
Data augmentation is an effective way to increase data efficiency for labeled
data. Data augmentations for 3D detection generally come in two forms: global
augmentations like scene rotations, or local augmentations like ground truth aug-
mentation, where crops of ground truth objects from the training set are inserted
into the scene. Pasting ground truth objects into the scene has been shown to
be extremely effective on various 3D detection datasets [64,25,8,66,70,65,30].
However, these augmentation techniques are typically limited to the labeled
training data. A simple way to incorporate unlabeled data into training is pseudo
labeling, but naively applying existing 3D data augmentation policies to pseudo
labeled frames has an intrinsic limitation, i.e., pseudo labeled frames contain nu-
merous false positive/negative bounding boxes and points. Several recent studies
on 3D pseudo labeling [4,44] have tried to use large-capacity teacher models to
mitigate this issue, but the intrinsic pseudo-labeling errors persist. Here, we seek
to an alternative approach: mitigating the pseudo labeled errors by new data aug-
mentation policies.
Another challenge is how to effectively combine labeled and unlabeled data
via data augmentation. Previous approaches treat pseudo-labeled frames as
a whole and do not recognize the compositional nature of 3D point clouds
scenes [4,44]. This limits the diversity of training data. A simple way to fuse la-
PseudoAugment 3
PseudoFrame PseudoBBox PseudoBackground
Labeled frame Pseudo labeled frame
Augmented frames
Original PseudoAugments
Fig. 2: Visualization of PseudoAugments. PseudoAugments contain three
new data augmentation policies: PseudoFrame, PseudoBBox, and PseudoBack-
ground. PseudoFrame replaces the labeled frame with a pseudo-labeled frame
and drops points of low-confidence bounding boxes in the pseudo-labeled frames.
PseudoBBox pastes high-confidence bounding boxes and corresponding point
clouds from a pseudo-labeled frame to a labeled frame. PseudoBackground re-
moves all points within bounding boxes in a pseudo-labeled frame, and replaces
the background point clouds in the labeled frame with the background point
clouds of the pseudo-labeled frame. The augmented frames are used as labeled
frames during training.
beled and pseudo-labeled frame is to generalize the existing copy-pasting object
data augmentation to leverage unlabeled objects. Interestingly, we observe that
only pasting objects between labeled and pseudo-labeled frames is not enough
[64,25,8,66,70,65,30], because we miss out the diverse background scenes in the
pseudo labeled dataset. Especially for 3D point clouds, more than 90% of the
points are backgrounds, which provide critical ingredients for 3D detectors to
learn to detect objects in new scenes. Thus, it is necessary to develop a set of data
augmentation policies that take advantage of both foreground objects and back-
ground points in the pseudo labeled frames along with labeled frames to generate
combinatorial number of point clouds.
In this work, we propose a set of data augmentation policies tailored for
pseudo labeled data, named PseudoAugments. As shown in Figure 2, our Pseu-
doAugments contain three new data augmentation policies: PseudoFrame re-
moves low confidence points, PseudoBBox pastes pseudo objects onto labeled
scenes, and PseudoBackground swaps the background point clouds between la-
4 Z. Leng et al.
beled and pseudo-labeled scenes. All our augmentations allow pseudo-labeling
uncertainty, and only make use of points of frame, object, and background with
high-confidence. PseudoAugments significantly increase the diversity of training
data by enabling a combinatorial number of new fused training scenes, including
1) ground truth objects on pseudo labeled background scenes, 2) pseudo labeled
objects on ground truth background scenes, and 3) pseudo labeled objects on
pseudo labeled background scenes, which greatly enrich the diversity of training
data.
Based on PseudoAugments, we develop an auto data augmentation frame-
work named AutoPseudoAugment to learn the best augmentation policies. Our
AutoPseudoAugment is based on population-based training (PBT) and searches
for the best augmentation policies online at different training stages. On top of
PBT, AutoPseudoAugment uses the top-performing models in previous genera-
tions as an ensemble of teachers to pseudo label unlabeled data, which further
boosts the quality of pseudo labeled data without the need of training a sepa-
rated set of high-capacity teacher models [4,44]. AutoPseudoAugment extends
PBT beyond simple hyperparameter tuning by introducing population-based
distillation and creates a virtuous cycle between students and teachers, where
good teachers in previous generations improves the quality of student models,
which become better teachers to pseudo label for future generations.
Our main contributions can be summarized as follows:
1. PseudoAugments: unifying data augmentation and pseudo label-
ing. We identify data augmentation and pseudo labeling are complementary
and introduce PseudoFrame, PseudoBBox, PseudoBackground data aug-
mentation policies to take advantage of the composability of unlabeled 3D
point clouds while mitigating errors.
2. AutoPseudoAugment: efficient one-shot framework for PseudoAug-
ment. Our framework extends PBT by introducing population-based dis-
tillation. AutoPseudoAugment does auto hyperparameters search and self-
training in one-shot, which reduces the training cost.
3. Extensive experimental evaluations. We demonstrate PseudoAugments
generalize to different network architectures, model sizes, and datasets. In
addition, AutoPseudoAugment outperforms both state-of-the-art auto data
augmentation method (PPBA [8]) and pseudo labeling [4]. In particular,
leveraging unlabeled data, AutoPseudoAugment requires 10% of labeled run
segments to achieve similar performance as PPBA training on 30% of run
segments and nearly matches the model performance trained on all labeled
data without data augmentation, shown in Figure 1.
2 Related Work
2.1 Data augmentation
Data augmentation has been widely adopted to improve the performance of mod-
els trained with supervised learning, such as image classification[55,10,60,49,29,13,67],
摘要:

PseudoAugment:LearningtoUseUnlabeledDataforDataAugmentationinPointCloudsZhaoqiLeng1,ShuyangCheng1,BenjaminCaine2,WeiyueWang1,XiaoZhang1,JonathonShlens2,MingxingTan1,andDragomirAnguelov1Waymo1,Google21flengzhaoqi,weiyuewang,tanmingxing,dragomirg@waymo.comAbstract.Dataaugmentationisanimportanttechniqu...

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