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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Intelligent Tracing and Process Improvement of Pathology Workflows using Character Recognition</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Markus Hatlem</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Fazle Rabbi</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Patrick Stünkel</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Friedemann Leh</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer science, Electrical engineering and Mathematical sciences, Western Norway University of Applied Sciences</institution>
          ,
          <country country="NO">Norway</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Department of Pathology, Haukeland University Hospital</institution>
          ,
          <country country="NO">Norway</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Faculty of Social Sciences, University of Bergen</institution>
          ,
          <country country="NO">Norway</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>A pathology laboratory processes various types of tissue and cell specimens and plays a vital role in the diagnostic process. However, pathology departments are currently facing a significant challenge due to the steady increase in incoming specimens. Increasing the workforce to match the influx is generally not feasible, so Information and Communication Technology (ICT) is seen as a potential solution. One area where ICT can be applied is in process monitoring and tracing. The increase in incoming specimens has caused queues within the laboratory, resulting in more time spent locating and retrieving individual specimens. Existing methods of tracing specimens, such as barcodes or alphabetic sorting, also require manual labor, adding further overhead. In this paper, we propose a lightweight application of optical character recognition (OCR) for specimen tracing, as part of a larger research project to optimize pathology processes at a large regional hospital in Bergen. We present a specific solution that integrates into a general process monitoring environment, and we compare diferent implementation techniques, particularly edge detection and neural networks. Our preliminary results indicate that this implementation can achieve an accuracy of up to 93.41%, increase sorting speed up to 54% and save up to 35% of time spent in manual sorting activities. We conclude our findings with a general discussion and outlook onto other areas where this solution could theoretically be applied.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Pathology</kwd>
        <kwd>Image recognition</kwd>
        <kwd>Optical Character Recognition</kwd>
        <kwd>workflow</kwd>
        <kwd>process mining</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>Medical treatment begins with a diagnosis, and Pathology (the study of diseases) plays a
paramount role in the latter. By assessing morphological changes of cells and tissue at a
microscopic level, pathologists provide critical insights for diagnostics and guide subsequent
treatments. However, the preparation of tissue samples for microscopic analysis is a laborious
process involving numerous manual activities.</p>
      <p>
        At the same time, healthcare systems are facing a shortage of trained professionals in relation
to the growing demand for medical services, which is exacerbated by factors such as an ageing
population, widespread cancer screening programs and the prospect of personalized medicine
[
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. This scarcity of resources manifests itself in growing waiting lists, increasingly exhausted
personnel and overfull weekly schedules for healthcare professionals. Thus, it is crucial to
develop innovative solutions that optimize existing processes and reduce unnecessary manual
workloads, allowing healthcare professionals to focus on higher-value tasks that require their
expertise. This also applies to the diagnostic process provided by the Pathology lab.
      </p>
      <p>Eficient prioritization and optimal resource allocation are crucial for delivering timely and
high-quality patient care. Business Process Management (BPM) has emerged as a discipline that
is concerned with these issues and provides techniques for process discovery, monitoring and
analysis. By tracking the progress of tasks and monitoring key indicators, it enables healthcare
providers to identify bottlenecks, streamline workflows, and allocate resources efectively [2].</p>
      <p>Traditionally, tracing techniques for Pathology labs rely on barcode scanning. While this
facilitates the capture of important data points and enables traceability, it also introduces
additional manual overhead. As a result, capturing points throughout the process have to be
chosen carefully in order to not unnecessarily introduce extra work.</p>
      <p>In light of these considerations, we propose a novel method for enhancing the tracing
capabilities of existing process monitoring solutions via optical character recognition (OCR)
technology, which allows for more capture points throughout the process while imposing
little additional manual overhead. Our work builds on a previously reported process mining
project at a large regional hospital in Bergen (Norway) [3]. Concretely, we are addressing
two operative challenges of that Pathology department: Locating workflow items within the
process at any given time, as well as reducing time spent on manual activities related to
tracing. Moreover, we illustrate how this approach can contribute to the analytical challenge of
creating a comprehensive process model from the available data. Finally, we provide preliminary
quantitative results about how the solution can help to reduce manual labour and how it may
be improved in the future.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Background on Pathology Workflow</title>
      <p>To introduce the problem, that we are going to address in this paper, some background
information about the workflow in the Pathology lab is needed. We focus specifically on Histology,
i.e. the sub-field of Pathology that studies tissues, which stands for a majority of workload by
incoming specimen. Fig. 1 depicts an abstract overview of respective processes:</p>
      <p>After the initial registration (Accessioning) and a macroscopic examination (Grossing), relevant
regions of the tissue specimen are placed in cassettes, which are then subjected to a chemical
processing step and are eventually placed inside a parafin block (Embedding), with the original
cassettes serving as a frame for the block. We will therefor use the terms cassette and block
interchangeably. The parafin block is used to cut a section through the tissue on a microtome
(Sectioning). This thin slice is then placed on a glass slide, which is stained with chemicals that
highlight certain cell structures (Staining) before a protective coverslip is applied. With the
advent of Digital Pathology, the slide is scanned so that it can be accessed by the responsible
pathologist within a Picture Archive and Communication System (PACS) [4]. The latter provides
an image viewer with advanced zoom functionality, replacing the traditional microscope.</p>
      <p>Send
Final Report</p>
      <p>Diagnostic
Reports</p>
      <p>Additional
Analysis</p>
      <p>Request
8.
"Microscopic"
Analysis</p>
      <p>Block
Archive</p>
      <p>Digital
Images</p>
      <p>Slides
6. Staining
Stained
Slides
7. Scanning
1. Accessioning
2. Grossing
3. Processing
4. Embedding
5. Sectioning
Specimens</p>
      <p>Cassettes</p>
      <p>Processed
Cassettes</p>
      <p>Blocks</p>
      <p>An important aspect of the Pathology workflow is
the fact that the "final" “ Microscopy” stage may generate Case
additional work for the laboratory in the form of orders caseID
for further “analysis”. With analysis, we mean a type of priority
stain that highlights specific morphological structures
(often based on Immunohistochemistry (IHC) where an- 1..*
tibodies and not chemicals induce the staining) but one SpecimenConatiner
may also perform molecular analysis of the existing specimenType
tissue. Note the possibility for loops in the net structure
in Fig. 1: If the available image material is not sufi- 1..*
cient to provide a conclusive diagnostic report yet, the
pathologist may order additional analyses. This means Block
that blocks, which were archived after sectioning, are blockID
to be retrieved and put again through the laboratory 1..*
workflow pipeline.</p>
      <p>Fig. 2 contains an abstract domain model, which illus- Slide
trates this situation: A single case may comprise several slideID
specimen containers, which may result in several cas- stainType
settes/blocks, which again turn into several slides. This
amlsinoinexgaaclegrobraitthemstsh, ewahpicphlicaaretiobansoedf tornadtihteiocnaasle-pcreonctersics Figure 2: Pathology Domain Model
view. However, due to the aforementioned composite
nature of cases in Pathology, the same activity will occur multiple times (depending on the
number of blocks and slides) within one case execution.</p>
      <p>This situation is comparable to the one described in [5], where lab visits are comprised of
several lab tests, which motivates the need for a PROCLETs framework [6]. A peculiarity of
the Pathology domain, however, is that all these case artefacts (specimen containers, cassettes,
slides) are being worked on in the lab simultaneously while the case is not concluded yet. Thus,
the duration of cases varies greatly due to the high degree of heterogeneity: For instance, a
small skin biopsy specimen generally results in a single block and single slide while a full
prostate resection can produce up to 150 blocks with even more slides, depending on how many
additional analyses are requested by the responsible pathologist.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Problem Statement: Tracing</title>
      <p>In [3], the third and fourth author presented an ongoing project at Haukeland University
Hospital in Bergen, which combines process mining, simulation, and optimization methods
with the final goal to improve the overall turnaround times of the Pathology lab. While, that
work was focusing on how to extract the raw data from a laboratory information system (LIS) to
produce a process model and the organizational, technical, methodological, practical, and social
issues associated with this activity, this paper focuses on the issues related to tracing.</p>
      <p>The foundation for every process mining (and thus also most process analysis) activity is
event logs. Bose et al. [7] mentioned three main issues w.r.t. data quality of such event logs: (i)
the event log does not contain events that really happened, (ii) the event log contains more
events than reality, and (iii) real events are concealed in the log. In this work, we focus on that
ifrst issue. This generally applies to all purely physical workflows. For such workflows, without
any form of automatic tracing, all events have to be entered manually. This causes a serious
overhead in terms of manual labour.</p>
      <p>In manufacturing processes, two
approaches for automatic tracing have emerged:
Barcodes (1-D, 2-D, QR) and Radio-Frequency
Identification (RFID) . RFID comes with the
advantage of being very eficient and
capable of recognizing multiple items
simultaneously. Its main disadvantages being, that it
is harder to locate single items and the costs
of RFID tags and scanners are significantly
higher compared to barcodes [8]. The
Pathology lab at Haukeland has adopted a tracing
solution based on barcodes: Specimen con- Figure 3: Cassette Tag Layout
tainers, blocks, and slides are tagged.</p>
      <p>Fig. 3 illustrates the layout of a
cassette/block. The most central piece of tracking information is a 2-dimensional barcode (data
matrix), which contains a unique item identifier, that is assigned by the LIS. The lab technicians
working at the workflow stations scan this data matrix when they start working on an item,
such that the respective event is logged by the LIS. The remaining information in the form of
regular text provides human-readable semantic context information, i.e. year of the case’s first
registration, the unique case number, the number of the block within the case and a hospital
identifier. This information helps to quickly discover blocks belonging together in a case and in
what order they appear, rather than scanning multiple barcodes for this purpose.</p>
      <p>While the LIS, partly functioning as a workflow-aware information system, logs the majority
of capture points in the “Histopathology workflow” execution, some activities are completely
untracked. This applies specifically to the “ block archive”, see centre of Fig. 1. When a block
has been sectioned, the produced slide is sent on to staining and the block is added to the
archive queue. Here, it has to remain accessible in the case that additional analyses are ordered.
Currently, the lab at Haukeland has no mechanism in place for registering blocks coming in and
out of the archive. In order to make the retrieval possible, all blocks have to be sorted manually in
alphabetical order (year → caseID → blockId). This generally binds one lab technician resource
to the block archive every day. At the same time, introducing barcode scanning into this station
would not create any significant benefit because the LIS has no tray management functionality
for archive locations and because barcode scanning of large batches creates significant manual
overhead. The latter is also the reason why there are several workflow stations where the
respective event does not exist in the event log.</p>
      <p>Fig. 4 depicts a Petri net (a refined variant of Fig. 1) serving as the process model (top) and
an example log (bottom) that was replayed on that net. The example shows the execution of a
single case with two blocks, where during microscopy an additional analysis is requested (see
Token columns). Events that are highlighted in red mean that the respective events are not
present in the log, which we aim to uncover with this work. “Missing out” on certain capture
points also causes problems when process artefacts get lost. This situation, rightly so, occurs
very seldom. However, when it happens, it can tie up multiple human resources who must
invest their time in trying to locate the missing item because the information given by the LIS
is not suficient. In the worst case, this can impair patient safety, if the item cannot be found.</p>
      <p>Our main objective with this work is to introduce additional capture points into the process
without causing much additional overhead, providing the following benefits:
• Reducing the amount of necessary manual labor in the archive would partially free up at
least one lab technician, allowing them to provide support at other workflow stations.
• Additional capture points will make it easier to locate individual blocks in the process.
• The extra capturing points in the event log allow producing a more comprehensive process
model, which allows for more accurate simulation results.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Related work</title>
      <p>In [9] the concept of a specialized laboratory information system is introduced. These systems
are characterized by the need to perform a limited number of functions extremely well, as
opposed to attempting to fulfill the needs of an entire laboratory [ 9]. The article outlines four
pillars to consider when developing an in-house solution. These four pillars are scalability,
building a design team, support costs and total cost of ownership versus long-term benefit.
It is crucial for the proposed solution to fulfill the requirements of a specialized laboratory
information system and, therefore, should take these four pillars into account.
Accessiong
:finish</p>
      <p>Grossing
:start</p>
      <p>Grossing
:finish
in_Archive
Archive_queue
b
b</p>
      <p>Block
archived</p>
      <p>Block
retrieved</p>
      <p>in_Embedding
in_Staining</p>
      <p>Staining_queue</p>
      <p>in_Sectioning
b
b
b</p>
      <p>b
Scanning_queue</p>
      <p>Staining
:finish</p>
      <p>Staining
:start</p>
      <p>Sectioning
:finish
Case</p>
      <p>Hanna and Pantanowitz outline the history of barcodes in pathology [10]. They presented
diferent types of codes including 2-D data matrix codes which is also used at the Haukeland
pathology lab. Additionally, they detail how hospitals have improved the scanning performance
with barcodes and improved eficiency. They explain how scanning could fail and mentioned
some measures to reduce the risk of failure. Some of these challenges such as print quality are
in_Processing
Embedding_queue</p>
      <p>Sectioning
:start
Token
B23 12345
B23 12345 01
B23 12345 02
B23 12345 01
B23 12345 01
B23 12345 02
B23 12345 02
B23 12345 01
B23 12345 01
B23 12345 02
B23 12345 02
B23 12345 01 01
B23 12345 02 01
B23 12345 01 01
also relevant to the OCR solution proposed. One significant benefit of incorporating barcode
based tracking system is the potential to eliminate mistakes in labeling and enhance patient
safety, leading to a decrease in adverse incidents [10]. However it is problematic to scan large
number of barcodes at the same time. Since image processing techniques have been improved
over the years, it can also be used for tracking laboratory samples at pathology lab.</p>
      <p>In 2009, Buese looked at adapting lean workflow models to histology labs [ 11]. He introduced
the concept of lean manufacturing, which is characterized by unitary production, minimal
waste, and customer-driven production processes (referred to as "lean"). He initially provided
a historical background of workflow methods, tracing their origins back to the automotive
industry and illustrated how these management techniques evolved to encompass concepts
of quality control and total quality management. Buese demonstrated the application of these
methods in histology labs. The article summarizes the findings from 25 histology facilities that
implemented management tools. Based on this data, it is extrapolated that labs handling over
20,000 cases annually derive greater benefits from incorporating these methods, although all
25 hospitals observed an improvement in performance. The article concludes by proposing 13
changes to enhance workflow in histology labs.</p>
      <p>In Zayas et. al., [12], a peer-reviewed analysis of 123 articles related to automation approaches
in various industries is conducted to identify opportunities for workflow automation in
healthcare. The authors highlight specific characteristics which promotes automation. The paper
presented diferent tasks that can be automated at diferent stages such as low-, semi- and fully
automated tasks. The level of automation achieved is closely related to the clarity and precision
within which the task is defined.</p>
      <p>Object centric process mining [13] can deal with divergence (multiple instances of the same
activity within a case) and convergence (one event may be related to diferent cases) related
problems. However, it does not ofer a solution for tracking cassettes and slides carrying
laboratory samples in pathology workflows or their subsequent analysis.</p>
      <p>Zhou et. al., introduced an eficient and accurate scene text detector (EAST) in [ 14]. EAST
is a fully convolutional neural network designed to achieve both eficiency and accuracy. The
authors provided detailed information about the image processing pipeline and explain the
decisions made regarding neural network training, including the choice of loss function, optimizer,
and number of batches. To evaluate the performance of EAST, quantitative and qualitative
experiments were conducted using three publicly available benchmark datasets: ICDAR 2015,
COCO-Text and MSRA-TD500. The results showed that the proposed algorithm outperformed
existing methods in terms of enhanced performance while also running significantly faster
when applied on the standard benchmark dataset [14]. In our work, we have tweaked
existing techniques for character recognition and incorporated them into process engineering to
streamline pathology workflows.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Proposed Method: Specimen Tracing with OCR</title>
      <p>In order to address the issue described in Sect. 3, we present a character recognition image
processing component, which serves as a lightweight tracing mechanism. This component
exploits the human-readable information that is attached to the process artefacts (i.e. blocks
and slides), see Fig. 3. We expect this approach to be applicable for any physical process, that
has not yet adopted Barcode or RFID technology, because it only relies on the human-readable
textual information, which we expect to be present anywhere human workers are involved.
Moreover, we illustrate how the image processing component can be incorporated into existing
workflow execution and process mining environments, where it provides improved traceability.</p>
      <sec id="sec-5-1">
        <title>5.1. Image Processing Component</title>
        <p>Image processing is the central part of our proposed solution for improving the tracing
capabilities within the pathology lab. The goal of image processing is to analyse, manipulate, and
extract meaningful information from digital images. It is used for extracting relevant features,
and enabling automated interpretation. Image processing often involves pre-processing steps
where certain aspects of the image are manipulated beforehand. This field can be divided into
the subcategories: text extraction, facial recognition, and vision systems. Our method focuses
on text extract, also referred to as OCR, i.e. “turning the text into analysable, editable, and
searchable data.” [15]. Machine learning has been successfully applied in OCR. However,
existing machine learning tools for image processing either need to be trained using a large dataset
which requires a lot of heavy computing power, or need to be fine-tuned with custom image
processing techniques. Our proposed framework includes an image processing component
which has been fine-tuned based on two techniques. These techniques have been selected based
on a sample dataset containing images of containers with a number of cassettes.</p>
        <p>These two techniques are optimized for pathology cassette detection. Two diferent image
processing pipelines have been used; one is built using various functionality from OpenCV [16];
and another one is built using a neural network. Fig. 5 depicts these two processing pipelines: (i)
Cassette reader pipeline with Edge Detection (ED); and (ii) Cassette reader pipeline with Eficient
and Accurate Scene Text detection (EAST).</p>
        <p>The cassette reader pipeline with edge detection (Fig. 5 left) applies filters and customized
contour detection for reading cassettes. It takes an image of a container with many cassettes
as input and applies gray scale filter and bilateral blur filter to smooth out noise. The pipeline
includes a sharpening step where objects boundaries are detected using an adaptive threshold
which binarize the image into black and white pixels. This sharpening technique increases the
outline of cassettes edges. The pixels are then eroded to remove noise. Contour detection is
also used for noise removal of small contours, and then contour detection is applied again for
locating and reading cassettes information. This pipeline uses Tesseract [17], or more specifically
PyTesseract which is a wrapper for Google’s Tesseract-OCR Engine for text recognition. The
Tesseract-OCR is already trained for text recognition, and therefore it simplifies the task of
extracting the textual information from cassettes. We have chosen Tesseract as it is open source
and freely available, even though the performance may not be the best when compared with
other commercial software [18].</p>
        <p>The cassette reader pipeline with EAST (Fig. 5 right) is a neural network based approach
using a fully convolutional network [14]. EAST requires an image resolution to be a multiple of
32 and therefore the pipeline checks for the resolution and adapts to the requirement by padding
each side with black pixels if required. In this pipeline, the output of the neural network is
parsed until the vertices of each piece of text is extracted. At this point, all 4 text fields of each</p>
        <sec id="sec-5-1-1">
          <title>Cassette reader pipeline with edge detection</title>
        </sec>
        <sec id="sec-5-1-2">
          <title>Cassette reader pipeline with EAST</title>
          <p>Image of a container
containing cassettes
Smoothing
- Gray-scale filter
- Bilateral blur filter
Sharpening object boundary
• Binarize the image with
adaptive threshold</p>
          <p>Contour detection to</p>
          <p>noise removal
Contour detection to
locate cassettes</p>
          <p>Text recognition
with Tesseract-OCR</p>
          <p>Engine</p>
          <p>Image of a container
containing cassettes</p>
          <p>Is image
resolution</p>
          <p>in a
multiple of
32?</p>
          <p>Yes
Neural network
Detection of 4 text
fields of cassettes
Custom merge
algorithm to combine
text fields of cassettes</p>
          <p>No</p>
          <p>Padding each side
with black pixels
cassette are extracted. However, to detect the boundary of all the text on each cassette, a custom
merging algorithm is employed. This merge algorithm checks the distances between the box
and pads them dynamically based on the image resolution until all text fields are merged or
removed in case if they are found to be too small. The cassettes are then considered located. Fig.
6 shows a screenshot of the results of image processing component.</p>
        </sec>
      </sec>
      <sec id="sec-5-2">
        <title>5.2. Architectural Integration</title>
        <p>The purpose of the image processing component is to identify cassettes and record their locations
at various checkpoints in the process flow. The image processing component ofers two major
functionalities: tracking and locating cassettes. Both functionalities are exposed via a REST API
and thus can be incorporated into arbitrary frontends.</p>
        <p>The cassette tracking API takes an image file and a parameter deciding over processing
pipeline as inputs. The API outputs a JSON object containing the coordinates of recognized
cassettes and texts field contents. Moreover, the application creates respective events in a log
ifle every time a cassette is recognized and when a cassette is retrieved from the archive. This
specialized log file is merged with the main event log to form a comprehensive event log.</p>
        <p>Fig. 7 shows how this component fits into the general framework of our project. The LIS
serves as the primary operative information system and also as a kind of process execution
engine since it is aware of the Pathology workflow. The data generated by the LIS serves as the
foundation for the creation of a cleansed event log, which is provided by an Extraction, Load &amp;
Transform (ELT) component. Details about this component can be found in [3]. The event log is
the basis of the process mining activities and succinct simulation and optimization components.
The novel part, here, is the image analysis component. It simultaneously serves as an operative
system as well as an analytic system.</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>6. Evaluation</title>
      <p>The performance of the image processing component is crucial for the applicability of our
proposed approach. Table 1 and 2 below present the results obtained from image processing
pipeline with edge detection and EAST for the identification of cassettes in four representative
images. These images were captured at equal distances. The images were taken using an
iPhone 13 with a resolution of 3024x4032. The evaluation and processing of the images were
done on a windows machine. To achieve the DPI resolution required by Tesseract the images
were taken from a close proximity. It also ensures that no details from the images were lost.
Consequently, a full image of tray containing 150 cassettes were not feasible to use, instead
smaller tiles containing between 37 and 49 cassettes were used. The results are expected to
scale with cameras that are able to capture images with similar text sizes and higher resolutions.
The only diference would likely be an increase in runtime with larger image sizes.</p>
      <p>Cassettes are classified into diferent categories based on the OCR tool’s performance. Fully
recognized cassettes refer to cases where the OCR tool successfully reads all the data present on
Plans</p>
      <p>Predictions</p>
      <p>Optimization</p>
      <p>Image Processing augments</p>
      <p>Tracking API
interacts Locating API
foundationFor
the cassette. Partially recognized cassettes indicate instances where the OCR tool only partially
recognizes or fails to recognize some of the text on the cassettes, although the cassette itself
is successfully located. False detections occur when the system highlights an area that does
not contain a cassette, possibly due to noise or erroneous detections. OCR errors correspond to
cases where the data on a cassette is recognized, but there are errors in the data itselfr.</p>
      <p>The edge detection model demonstrates an overall accuracy of 77.84% (130/167) in cassette
detection, while EAST achieves an average accuracy of 93.41% (156/167) in localizing cassettes.
However, this accuracy improvement comes at the cost of an average runtime increase of 22.01
seconds compared to edge detection. Some instances of false detections have been observed in
our experiments, wherein the program erroneously identifies a cassette that does not actually
exist. To estimate the time required for manually sorting cassettes, we conducted observations
in the archive room alongside a lab technician on a randomly selected day. Within a fixed time
span, it was determined that, on average, 10.78 cassettes are sorted per minute when the process
is performed manually.</p>
      <p>The graph in Fig. 8 presents the progress of produced blocks by the lab over time. The bar
chart below shows an estimate of the number of hours the lab technicians have dedicated to
sorting, based on the data gathered through observation. There is also an estimate of how
much time would have been saved if they utilized the EAST based sorting in its current state,
including the time for manual error correction.</p>
      <p>In 2022, the pathology lab sorted 185065 cassettes. If the sorting process were conducted at
the average manual speed measured here, which amounts to 647 cassettes per hour, it would
require approximately 286 hours of work. However, by implementing the EAST-based sorting
method with manual error correction, which currently achieves an average speed of 1000.333
cassettes per hour, it would be possible to complete the sorting within 185 hours. This would
allow the pathology lab to reduce sorting time by 101 hours, resulting in a 35.32% decrease in
time spent on sorting activities, while simultaneously enhancing traceability.</p>
    </sec>
    <sec id="sec-7">
      <title>7. Conclusion</title>
      <p>In this paper, we have presented an automated tracking system for lab samples using image
processing and its integration with a process execution engine. The technique we presented
for tracking lab samples will contribute to process improvement, as the tracking data can be
used to leverage process mining output. Empirical evaluations were conducted to assess the
efectiveness of the proposed method. Accurate recognition of text from the labels of lab samples
is crucial for this project, thus two diferent image processing techniques were tested: one is
based on edge detection and the other is based on a neural network for text detection named
EAST. The image processing pipeline with EAST outperformed the edge detection method,
achieving an accuracy score of 93.31%. Although EAST exhibited a slightly longer runtime
compared to the edge detection method, its accuracy is higher.</p>
      <p>Furthermore, a comparison of sorting time with and without the image processing tool was
performed. The experimental results demonstrated that utilizing EAST for sorting enabled the
processing of 54% more cassettes within a given time frame compared to the current manual
sorting approach. Based on our calculations, employing EAST for sorting would have saved
a total of 101 hours in 2022, corresponding to 35% reduction in sorting time. Although the
evaluation shows promising results, there is scope for improvement. The current accuracy
of the system necessitates manual oversight and error correction. Taking into consideration
the current runtimes of 1 minute and 56 seconds, a theoretical maximum of achieving 100%
accuracy and full automation would enable the sorting of approximately 86.38 cassettes per
minute, resulting in a substantial 701% increase in the number of cassettes sorted per hour.
However, it is important to note that this calculation assumes consistent runtimes and anticipates
technological advancements that can surpass the current error rate observed in manual sorting.
The primary drawback of the current models resides in their limited OCR performance, estimated
at 62% (97/156). Consequently, the remaining 38% of cassettes would require manual labeling.
Nevertheless, despite this suboptimal performance, the EAST model continues to outperform
manual sorting in terms of eficiency.</p>
      <p>In future work, we plan to explore the development of a custom machine learning model
specifically designed for cassette detection, instead of relying on of-the-shelf solutions.
Developing a custom machine learning model will require a substantial volume of training data,
containing labeled images of cassettes and slides captured from various angles.</p>
    </sec>
    <sec id="sec-8">
      <title>Acknowledgments</title>
      <p>The paper is partially funded by the Western Norway Regional Health Authority through
project “PiV – Pathology services in the Western Norwegian Health Region: a centre for applied
digitization” (PIV F-12563-D11779).
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