Paul Slebodnick, James Tagert, Bruce N. Nelson, Darren C ...

Paul Slebodnick, James Tagert, Bruce N. Nelson, Darren C. Melhuish,
Kimberly Santangelo, John Wegand, Diane Lysogorski,
and Edward J. Lemieux

Current assessment methods are expensive and time consuming
Approximately 65 man day effort with significant logistical requirements
Typically takes 3 months to assess a Carrier’s Topside Coatings
Determining the affected area of many of the parameters assessed
are based on estimates from trained coatings inspectors and hence
are subjective
Topside coatings parameters including corrosion damage, coatings non‐
uniformity, and the extent of flaking, blistering, and delamination are
currently assessed manually –Significant inspector to inspector variance
can result in improper assessment of these parameters
Scheduling and initiating unnecessary maintenance actions
Delaying proper action with minimal corrective costs thereby allowing further
degradation to the topside coating and unprotected freeboard surfaces

Inspectors estimate the extent of specific coatings anomalies by zone
Corrosion (ASTM D610 and ASTM F1130)
Delamination (ASTM D610)
Blistering (ASTM D714)
Cracking (ASTM D661)
Checking (ASTM 660)
Caulking (ASTM D4214 Method A)
Assist in decision making process for overhaul planning
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For Each Zone Human Inspectors:
Determine Affected Area (Total Area Affected)
Within the Affected Area associate the appropriate rust grade density
(Distribution of Corrosion)
ASTM F1130
Scale Used To
Determine
Affected Area
ASTM D610
Scale Used
To
Determine
Corrosion
Distribution
in the
Affected
Area
Inspector to inspector estimation variation using these and similar
scales makes it difficult to properly prioritize maintenance and
optimally preserve US Navy Ship topside coatings

Surface Contact Measurements
Tensile Adhesion (ASTM D4541)
Color (CIEL*a*b*) & Spectral Gloss
Dry Film Thickness
Contact Measurements Of Coatings
Condition Made With Instruments
that Make Direct Contact With Ship’s
Hull
Multiple Personnel Lifts (JLGs) and
Barges Are Typically Required To
Support These Measurements

Size and complexity of Carrier Zones or equivalent topside areas of
Surface Ships make it difficult for human inspectors to estimate the
affected areas and distributions
Potential variations amongst inspectors for extent of affected area
and density of defects
The log scale associated with ASTM D610 can make “fitting”
corrosion grades misleading
Not all areas are accessible for visual or physical inspection
Image Depicting Approximately 1/3 of a
Carrier Zone
Note that Different Regions Within a Zone
(e.g. Hull versus Overhead) May Have Very
Different Affected Areas and Distributions
For Each Type of Damage Scenario

15 Freeboard Zones
7 port, 7 starboard, 1 stern
14 Catwalk Zones
NACE Certified and Shipboard Corrosion Assessment
Trained (S‐CAT) engineers and technicians
5 persons x 5 days
6 JLG’s
2 Pier side, 4 on Barges
8‐10 Ship’s Force support of barge/JLG logistics
Report Generation 4 additional weeks
65 Man-Day Effort Excluding
Report Generation

Image collection performed by two trained technicians
2 persons x 3 days
External logistics requirements: patrol boat support
One day, 2 man crew
Algorithm execution and automated report generation
by trained technician
1 person x 2 days
10 Man-Day Effort Including Report Generation
Over a Six Fold Reduction in the Level of Effort
Required to Perform the Topside Assessment
Reduced Logistics Requirements

Collect “Overview” and Zoomed‐In Images
Overview Images Depict Freeboard Areas of Approximately 90 feet in
Width by 70 feet in Height
Zoomed‐In Images Depict Freeboard Areas of Approximately 20 feet in
Width by 15 feet in Height
Green box denotes an “Overview Image”
Red and blue boxes denote “Zoomed-in
Images”
Images are Collected Without Panning
the Camera – The Photographer Walks
the Hull
All images collected from approximately
a 100 foot distance
Images were collected pierside and from a patrol boat. Over three days
over 3000 images depicting the USS NIMITZ freeboard were collected for
automated analysis

Reduce the number of images that make up the image set that fully
covers a Carrier Zone or the equivalent surface ship topside surface
area from greater than 300 images to 6 –30 images.
Collect images at high resolution, resize images as required for various
automated analysis algorithms
Objective: Ease and Expedite Image Collection
Eliminate requirements for patrol or other boats when
photographing the sea facing topside surfaces
Collect all images from available piers
Necessitates image collection from distances up to 1300 feet
Objective: Reduce Image Collection Logistics Requirements
Allow for some minor editing of imagery prior to automated
analysis
Cropping of imagery to remove sky, sea, and structure such as pierside
infrastructure and booms
Objective: Ease Image Collection Requirements

Collect 6 -15 “Overview images” that depict a Carrier Zone or Ship Side
and edit images if required to remove sky, sea and structure. Collect
additional images of regions of interest to augment the image set.
Complete Zone Image sets should be 6 – 30 images.

Images below collected pierside from a distance of 1250 feet
Canon SX10IS – 16X Optical Magnification Canon EOS7D/Swarovski Spotting Scope – 38X
Optical Magnification
Image Detail From Above – Note Flaking Paint
can be observed at this imaging distance
Images above demonstrate the ability to
collect imagery with sufficient resolution to
observe coatings anomalies from a 1250 foot
camera to ship distance
Image Detail From Above – Note
Flaking Paint can be observed at
this imaging distance

Canon SX 30 IS
0.7X –24 X optical
magnification
Point and shoot ease
of use
50 % increase in the
optical magnification
compared to the
Canon SX 10 IS
Primary imaging tool
Digital Spotting Scope
(Carl Zeiss or Barska)
15X –45 X optical
magnification
Point and shoot ease
of use
Secondary imaging
tool used to ensure
that coatings
anomalies are not
missed by the Canon
SX 30 IS
Composite Tripod
(Swarovski or Gitzo)
Provides required
mechanical stability
to image from larger
camera to ship
distances
Lightweight, rugged
and easily
transportable to aid
the collection of
topside image sets

AFTCAT Consists of A Suite of Automated Algorithms Used
to Analyze Topside and Freeboard Image Sets
Topside Corrosion Detection Algorithm (TCDA) – Identifies and
quantifies corrosion damage in topside and freeboard images
Coatings Non‐Uniformity Algorithm –Provides a quantitative
measure of coatings non‐uniformity and can show areas where
topside overcoats have been applied.
Coatings Failures Assessment Algorithms – Identifies and
quantifies the extent of coatings delamination, flaking and
blistering
Aggregation Algorithms – Generate zone level condition
assessments from the individual image results
Automated Report Generation Algorithms – Generates reports in
standardized format for upload to Navy databases

TCDA
Most mature and tested AFTCAT algorithm
Based on the proven Tank and Void Corrosion Detection Algorithm
Calculates actual corrosion damage percentage for the image analyzed
Generates an output image that highlights identified corrosion using red image
overlays
Overview image as collected TCDA output image
Result = 0.04 % corrosion damage

TCDA output image
Result = 0.04 % corrosion damage
TCDA output image
Result = 0.10 % corrosion damage
Overhead regions became a region of interest as they had higher levels
of corrosion damage (and delaminated paint). The image set for this
zone was augmented with representative images from this region to
afford an optimal assessment of this zone’s corrosion damage

NRL has developed a unique image processing filter that highlights color hue and
textural variations
This filter is used as the first processing step in both the coatings non‐uniformity
and failure assessment algorithms
These algorithms work on topside imagery collected at a resolution of 3648 x 2736
pixels or higher.
Image as collected
Filtering enhances
coatings hue variations

Image as collected
Filtering enhances
roller marks and hue
variations
Image as collected
Filtering enhances
coatings
delamination
Image as collected
Filtering enhances
flaking paint and
blistering

Freeboard image as collected Filtered image. The coatings nonuniformity
algorithm produced an
8% non-uniformity value
Apply hue/texture enhancement filter to ship freeboard image
Break enhanced image into four equally sized full column and
four equally sized full row based sub‐images
Generate a course ten bin histogram for each image
Analyze the histograms to assess coatings non‐uniformity of
each sub‐image
Average results across sub‐images to generate an image level
coatings non‐uniformity percentage value

Image as collected Filtered image False color image
Apply hue/texture enhancement filter to ship freeboard image
Generate a course ten bin histogram for the filtered image
Group individual pixels from each of the histogram bins by color
–creates the false color image on the left.
Perform a spatial contrast analysis of the false color image –
identify and quantify coatings anomalies in the image. Note
that flaking, blistering and delaminated coatings have different
signatures allowing their extent to be individually determined

Image as captured provided to
coatings Non-uniformity algorithm
Overview image as collected
(3648 x 2736 pixels)
Resized image (1600 x 1200 pixels)
provided to the TCDA
Filtered Image – 36 % coatings non-uniformity
TCDA output image – 0.29 % corrosion damage

Aggregation Algorithms for the TCDA and Coatings
Failure Assessment Algorithm that generate zone level
assessment of damage extent and distribution have
been developed and are being tested
Report Generation Algorithms have been developed
and utilized in the Tank and Void CDA
Report Generation Algorithms will be developed when all
AFTCAT Algorithms are finalized
The final AFTCAT output is a report in a
standardized format that documents the
inspection and its results that is suitable for
upload to Navy databases

Digital photography and AFTCAT analysis of image sets
will allow topside coatings assessments and report
generation to be completed in one week at
significantly reduced costs
At least a six fold reduction in labor requirements
Reduced expertise and logistics requirements
Contact measurements of coatings adhesion and thickness
are not made –these measurement would be made if the
need is indicated by AFTCAT analysis
Images can be manually reviewed to assess automated
results
Inspection reports in standard formats afford better cross
platform comparisons and improved maintenance planning

The Authors Acknowledge the Support and
Guidance Received from the Naval Sea
Systems Command, Paint Center of
Excellence, as well as the Office of Naval
Research and the Office of the Secretary of
Defense
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