
TOWARDS TRUSTWORTHY MULTI-LABEL SEWER DEFECT CLASSIFICATION VIA
EVIDENTIAL DEEP LEARNING
Chenyang Zhao1, Chuanfei Hu1, Hang Shao2, Zhe Wang3, Yongxiong Wang3
1Key Laboratory of Measurement and Control of CSE Ministry of Education, School of Automation, Southeast University, Nanjing, China
2School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing, China
3School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China
{zhaocy, cfhu}@seu.edu.cn, shaohang@njust.edu.cn, 201440049@st.usst.edu.cn, wyxiong@usst.edu.cn
ABSTRACT
An automatic vision-based sewer inspection plays a key
role of sewage system in a modern city. Recent advances fo-
cus on utilizing deep learning model to realize the sewer in-
spection system, benefiting from the capability of data-driven
feature representation. However, the inherent uncertainty of
sewer defects is ignored, resulting in the missed detection
of serious unknown sewer defect categories. In this paper,
we propose a trustworthy multi-label sewer defect classifica-
tion (TMSDC) method, which can quantify the uncertainty of
sewer defect prediction via evidential deep learning. Mean-
while, a novel expert base rate assignment (EBRA) is pro-
posed to introduce the expert knowledge for describing reli-
able evidences in practical situations. Experimental results
demonstrate the effectiveness of TMSDC and the superior
capability of uncertainty estimation is achieved on the latest
public benchmark.
Index Terms—Trustworthy visual inspection, evidential
deep Learning, multi-label sewer defect classification, sewer
pipelines
1. INTRODUCTION
Underground sewage system is one of the most vital life-
lines in a modern city [1], which can guarantee the commu-
nity health, safety, and manufacture. Vision-based inspection
method is widely applied to maintain the underground sewage
system [2]. The internal situations across the sewer pipes
can be captured via a remote mobile vehicle, while the sewer
inspectors diagnose the defects with a long time of looking
at a screen. Such manual inspection is not only laborsome
and time-consuming, but also may cause ophthalmic diseases
during the high-frequency illumination of the screen. Con-
sequently, how to construct an automatic sewer inspection
method has long been a research topic attracting constant at-
tention in the field of sewer inspection [3].
Chenyang Zhao and Chuanfei Hu contributed equally to this work. Cor-
responding author: Chuanfei Hu (cfhu@seu.edu.cn).
Recently, deep learning model has received substantial
interest in industrial applications [4,5]. In the vision-based
sewer inspection community, deep learning also attracts in-
creasing attention from both academia and industry [6,7,8].
Here, we focus on the sewer defect classification in the set-
ting of multi-label, in which multiply defect classes in an
image are recognized simultaneously. Although these deep
learning-based methods have achieved acceptable perfor-
mances of sewer defect classification, while the inherent un-
certainty of sewer defects might not be considered sufficiently
in real-world applications [9]. For instance, some categories
of sewer defects are not appeared from historical data, in
sense that, the trained sewer defect classification model has
not seen these unknown defects which is the samples out of
knowledge. Existing deep learning-based methods [6,7,10]
for sewer defect classification could not describe the mag-
nitude of epistemic uncertainty across known and unknown
sewer defect categories. The model would be over-confident
to “trust” the prediction, resulting in the missed detection of
serious unknown sewer defect categories.
In this paper, we propose a trustworthy multi-label sewer
defect classification (TMSDC) method for unknown sewer
samples setting. To enable the multi-label sewer defect clas-
sification model to “know unknown”, we cast the task as an
uncertainty estimation problem via evidential deep learning
(EDL) [11]. EDL describes the uncertainty via a Dirichlet
distribution of class probability, which can be seen as an ev-
idence collection process via a deep neural network. The
collected evidence is leveraged to quantify the uncertainty of
sewer defect prediction, for instance, unknown sewer defect
would present a high uncertainty explicitly. Moreover, we in-
troduce the expert knowledge to model the uncertainty and
propose an expert base rate assignment (EBRA), in which the
realistic base rate can provide reliable diagnosis of sewer de-
fects in practical situations [12]. It is noteworthy that TMSDC
can quantify the uncertainty effectively of model whose capa-
bility of distinguishing the known categories would only be
weakened slightly. The main contributions are summarized
as follows:
arXiv:2210.13782v1 [cs.CV] 25 Oct 2022