GT-8K: World’s First Infrastructure Inspection Vehicle using
8K Video Technology
Narumi Kurihara

General Manager, Camera business promotion
Video Engineering Dept.
ASTRODESIGN, Inc.

1. Introduction

So far, 8K technology has developed mainly for broadcasting.
NHK Science and Technology Research Laboratories has beendeveloping 8K under the name of Super Hi-Vision since 2004 andbegan 8K broadcasting in 2018. During development, several large
scale specialized devices were used for filming, but for roughly
15 years, 8K equipment has become more compact, 8K TVs haveappeared on the market, 8K video compression technology has
advanced, and products such as 8K processing workstations haveentered the market.
Through this process, the characteristics of 8K have also
been widely researched, and applications in industry are highlyanticipated. One characteristic of 8K is that it can capture highdefinition state over a wide area. If an unexpected outcome isperceived from the overall image, the overall features can beanalyzed on a single image rather than attempting to join images
from multiple cameras. It is hoped that this will show the benefitsof 8K in industry. To apply a new technology such as 8K inindustry requires the desired objective to be achieved, but also thatthe technology is both practical and economical.
ASTRODESIGN has put effort into developing devices for
8K broadcasting and has commercialized successive products
including cameras, signal processing equipment, recorders anddisplays. Here we describe how we provided comprehensive
leading-edge technology, when it was needed, during completionof the GT-8K, the world’s first 8K infrastructure inspectioncar. We have conducted repeated trials since development
began, and now understand the effects of using 8K technology
for infrastructure inspection, so we are now ready to apply thetechnology. Here, we describe the development process, show
operation and results from the inspection system, and results
achieved in light of issues with current infrastructure inspection
practices.

2. Evolution of 8K equipment

ASTRODESIGN has worked on developing products since
the beginning of Super Hi-Vision development, and been broadly
involved in 8K products. As FPGAs have advanced, they became
a technology for processing 8K efficiently. They have been a highquality signal processing technology for broadcasting, contributing
to advancement of devices such as cameras. They are the eye ofthe system, the entryway for images, and an essential component
when considering industrial applications of 8K. Earlier 8K

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Kazutomo Yamamoto

Engineer
Mobility Spatial Information Department
MMS Technology Group
Aero Asahi Corporationcameras were large systems requiring much power, but their sizeand power consumption has been reduced, without decrease inperformance. These advances have greatly reduced the hurdles tousing 8K cameras in industry applications.
Currently, ASTRODESIGN has a lineup of two cameras forindustrial use, with model numbers AB-4815 and AB-4830/AC4829.
Both models can output 8K video (12G-SDI×4 channels) inreal time, to use the characteristics of 8K video. The AB-4815 is acompact camera with the main unit measuring 148 mm × 150 mm
× 241 mm, which outputs image-processed video and consumes
only 90 W of power. The other model, the AB-4830/AC-4829,
is separated into a camera head and a video processing unit. The
camera head is more compact, measuring only 65 mm ×65 mm
× 85 mm and weighing only 340 g. Including the AC-4829
signal processing unit, it only consumes 80 W of power. These
compact designs expand the range of possible non-broadcasting
applications.
Use of 8K video for industrial applications requires capture
as well as storage of the video and processing with CPU/GPU.
ASTRODESIGN has developed a hardware-based 8K recorder,
but we also developed a workstation able to receive the video
data to create a more flexible capture system. The AW-8800
workstation is able to receive 8K video from up to four camera
systems. For such a case, the system would be implemented
with four capture boards capable of transmitting and receiving■ Figure 1: 8K camera(left: AB-4815, right: AB-4830/AC-4829)■ Table 1: A B-4815 specifications
Item
Image sensor
Effective pixels
Lens mount
Frame frequencies

External dimensions
WeightSpecifications
Super 35 mm CMOS image sensor
Approx. 33 million
PL mount
59.94 Hz, 60 Hz, 50 Hz, 30 Hz, 29 Hz, 25Hz, 24 Hz
148 (W)×150 (H)×241 (D) mm
3.5 kg■ Table 2: AB-4830/AC-4829 specifications
Item
Image sensor
Effective pixels
Lens mount
Frame frequenciesExternal dimensions

WeightSpecifications
Super 35 mm CMOS image sensor
Approx. 33 million
Micro Four Thirds mount59.94 Hz, 60 Hz, 50 Hz
Camera head: 65 (W)×65 (H)×88.5 (D) mm
CCU: 210 (W)×133 (H)×370 (D) mm
Camera head: 340 g
CCU: 5 kg

four 12G-SDI channels installed in five-lane PCIe slots. The
workstation is also equipped with 16 U.2 NVMe SSDs in a
RAID configuration. The system can also be implemented with
8 GB DDR4 DIMM in 24 slots, so the system can record evenuncompressed high-bit-rate video data. The CPU has 56 cores, sothat workstation-based systems can be built for high-performanceand specialized applications, able to process 8K in real-time.
The 8K infrastructure inspection system described here is asimple configuration including four 8K cameras (AB-4815) andan AW-8800 workstation.
■ Figure 2: AW-8800 TAMAZONE workstation

ASTRODESIGN announced completion of joint developmentof GT-8K, a new measurement vehicle equipped with 8K video
technology to advance and increase performance in maintenanceof various infrastructure such as roads, railways and airports. It isa vehicle-mounted Mobile Mapping System (MMS) and is able torecord 8K video while travelling at highway speeds, linking it withpositioning data to collect accurate data at high speed. The Aero
Asahi Corp. mobile measurement vehicle technology combinedwith ASTRODESIGN’s high-quality video technology creates ahighly accurate and practical measurement system.
Since 2019, we have conducted repeated trials inspecting
tunnels, demonstrating that we achieved our goal of detecting
cracks on the order of 0.1 mm to complete the photographicsystem. Till now, we have been operating the GT-8K andintegrating the crack detection system with point cloud data.
Using the results, we have implemented industry applications of8K, delivering measurement services and the measurement data asa commercial product.
■ Figure 3: GT-8K (left) and GT-8K in operation (right)

4. Measurement system configuration■ Table 3: AW-8800 specifications
Item
CPUMemory
Drive
GPU
PCIe slots
ChassisSpecifications
Intel® Xeon® processor×2 (56-core)
DDR4-2666 8 GB×24
2.5” U.2 NVMe SSDx×16
NVIDIA® Quadro® P4000
PCIe Gen3×16 4-Lane
PCIe Gen3×4 (DMI) 1-Lane
5U Chassis, 28.7” (L) ×18.0” (H) ×8.54” (W)

3. GT-8K: World’s first infrastructure
inspection car

During the years of rapid economic growth in Japan, large
amounts of social infrastructure were built, including roads,
tunnels, and railways. As this infrastructure deteriorates,
managing maintenance is becoming more important, while atthe same time, a shortage of inspection personnel and increasing
inspection costs are becoming major issues. The Ministry ofLand, Infrastructure and Transport has designated infrastructure
facilities that were built 50 years or more in the past as deteriorated
facilities, and is working on policy to replace inspection, which has
basically involved close visual inspection, with technology.
On June 3, 2020, Aero Asa hi Cor poration andGT-8K consists of four 8K cameras, a video collection
workstation, high-output illumination and a laser scanner, allmounted on a vehicle.
The image capture component has 8K cameras with fixedfocus lenses, which send video signals to the components inthe vehicle. The cameras also have high-powered lighting
on both sides to ensure that the tunnel walls are adequatelyilluminated. The laser scanner component is equipped with a
Global Navigation Satellite System (GNSS) antenna, an Inertial
Measurement Unit (IMU) and a laser scanner. The GNSS is
not able to receive radio signals inside a tunnel, so the IMU
positioning measurements enable the system to record accurate
positioning data as the vehicle moves, even while in a tunnel.
Based on this positioning data, point cloud data is generatedusing the laser scanner. Overall control of the system and datacollection is done by a PC in the vehicle, and data collection canbe monitored in real time on a terminal in the vehicle as it moves.
All of this equipment is driven by a power supply installed under
the cabinet. The simplified system configuration enables theentire system to be installed on a single vehicle.
The laser scanner is able to acquire range data for one million
points per second. By combining this point cloud data with the8K video, an expanded image of the inside of the tunnel is created

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■ Figure 6: C apturing tunnel wall surfaces

with both location and image information.
The video and point cloud data are synchronized during
capture using a video synchronization signal (30 Hz TTL pulse).
The cameras output 30 Hz 8K video and the workstation isequipped with up to four 12G-SDI capture cards. The PC
receives uncompressed video, which is transferred to main
memory, and then written sequentially to the SSDs. The input
video data rate is 96 Gbps, and the application is optimized
to ensure that no data is lost. To enable monitoring of themeasurement status, the image data in the SSDs is also processed
to display it on a terminal as it is recorded.
Three or four cameras are used for measurement of the surfaceof tunnel walls. The number of cameras and lenses are selected
beforehand based on the tunnel shape, and the position andorientation of the cameras on the cabinet and the path of thevehicle are adjusted through prior simulation and at the site.

Data collection is then performed after tuning the lens focus andlighting conditions. To utilize the horizontal resolution of the 8K
video, the cameras are tilted by 90° facing the wall surface. To
capture an entire tunnel with inner circumference of 15 m, threecameras are used to capture the left-hand surface, and the vehicle
drives down the opposite late to capture the other half.
In this case, a single camera captures an area of 2.5 m × 1.4 m,
and each pixel represents an area of approximately 0.3 mm × 0.3
mm. We have targeted this 0.3 mm size when measuring cracks,
but there is a high contrast ratio between cracked areas (whichappear black) and the tunnel walls, so we are able to use thisdifference in contrast ratio to measure cracks that are smaller thanthe pixel size. In practical tests, we have been able to discriminate
cracks down to approximately 0.15 mm.
To capture from the vehicle while it is moving requires
suppression of motion blur. When capturing at 30 Hz andtravelling at 60 km/h, the vehicle travels roughly 550 mm during
a single frame. To suppress motion blur due to this motion, thecamera shutter speed must be increased. Using a shutter speed of■ Figure 4: GT-8K configuration■ Figure 5: GT-8K system schematic diagram
GNSS antenna
High-definition laser scanner
IMU

Synchronization signal

6G-SDI x 4ch
24Gbps12G-SDI
capture card
6G-SDI x 4ch
24Gbps

8K camera
AB-4815
Synchronization signal

8K camera
AB-4815

AW-8800, 8K video recording/processing workstation

DDR4 x 1212G-SDI
capture card

8K camera
AB-4815
Synchronization signal

Transfer video from each capture
card to memory
Data rate: 96 Gbps

6G-SDI x 4ch
YCbCr4:2:2 30Hz
24Gbps

8K camera
AB-4815
Synchronization signal

Laser scanner measurement module
Operator PC

PCI bus
PCIe Gen3, 8 lanes

CPU28 cores

DDR4 x 1212G-SDIcapture card

PCI bus
PCIe Gen3, 8 lanes

6G-SDI x 4ch
24Gbps12G-SDI
capture card

PCI bus
PCIe Gen3, 8 lanes

CPU28 cores

Transfer uncompressed image
data from memory to SSD
Data rate: 96 Gbps

GPUProcess video for monitoring using CPU,and output to monitor through GPU
Use bus idle time for image down-conversion and cropping (low-priority).

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DDR4‐26668GB
8GB
DDR4‐2666
DDR4‐2666
8GB

PCI bus
PCIe Gen3, 8 lanes

PCI bus
PCIe Gen3,16 lanes
MonitorDDR4‐2666
8GB… 8GB
DDR4‐2666
DDR4‐26668GB

DDR4‐2666
8GB… 8GB
DDR4‐2666
DDR4‐2666
8GB
DDR4‐26668GB
8GB
DDR4‐2666
DDR4‐2666
8GB

U.2 NVMe
U.2 NVMe
U.2 NVMeSSD
U.2 NVMe
SSD
SSD
SSD

U.2 NVMe
U.2 NVMe
U.2 NVMeSSD
U.2 NVMe
SSD
SSD
SSD

U.2 NVMe
U.2 NVMe
U.2 NVMeSSD
U.2 NVMe
SSD
SSD
SSD

U.2 NVMe
U.2 NVMe
U.2 NVMeSSD
U.2 NVMe
SSD
SSD
SSD

2.5' U.2 NVMe SSDs
x16

1/10000 s, image blur can be reduced to approximately 1.5 mm.
When conducting data measurements, target capture conditions
must be verified beforehand, and also adjusted at the site. The 8K
cameras and workstation provide advantages for achieving this inthat the system is simplified and has functions for real-time tuningat the site.
An expanded image of the tunnel is generated by combining
the 8K video with the point cloud data obtained when collecting
the data. The images are combined by projecting a mosaic of theimages onto a 3D projection surface generated from the laser datausing the position and orientation of the camera. The complete
expanded image is further processed to provide a record of theposition and shape of any cracks. Besides cracks, areas with water
stains, and where markings have been added manually in the past
are also isolated comparatively.
The expanded view image can be analyzed automaticallyusing image processing and can also be inspected visually by aninspector at a later date. The data is also archived, so any changes
detected in periodic inspections can also be used for forecasting
future changes.

5. Benefits of the 8K infrastructure inspection
vehicleCreating this expanded view from the video captured using
the 8K infrastructure inspection vehicle enables automation ofinspections, reduction in required personnel, increased accuracy,and greater stability of inspection quality. Compared with■ Figure 7: Tunnel expanded view

■ Figure 8: Image processing results■ Figure 9: Image analysis■ Figure 10: G
 T-8K inspection support

conventional periodic inspections, the labor and costs of the close
visual inspections, hammer testing and other tests required in thepast are reduced and on-site work is more efficient. The system
also supports diagnosis of tunnel shape and soundness, improving
the quality of the diagnostics that can be done.
Use of 8K cameras in the inspection system reduces thenumber of cameras needed and reduces the preparation andtuning time required. It can also be expected to help reducedifficulties and errors, and to simplify monitoring during image
capture. Image captured with the video cameras are consecutive
in time and with images taken from other viewpoints, they cancomplement each other to enhance the inspection. Even forimages that are difficult to discern due to the light and shadows ofa structure, other images can be used for the inspection, increasing
reliability and utility of the inspection. In particular, the system
is designed to maximize performance of the 8K cameras, so theexpanded view of the tunnel retains the color and texture of theimages. This makes the inspection similar to a visual inspection,
so that inspectors can use their experience gained in the past.

6. Conclusion

The increasing amount of deteriorating infrastructure isbecoming an urgent issue, and we have tested effective use of
8K video technology for work inspecting such infrastructure.
Digitalization of inspections promotes efficiency, and can also
increase reliability, so we can expect it to be used in an increasing
range of scenarios in the future. The characteristics and potentialof 8K are extremely well suited to the field of infrastructure
inspection, and we expect that even more successes and research
results will appear in the future.
In this case, we examined roadways and tunnels, but there
are also other infrastructure areas such as bridges, railways, watersupply and drains, gas and electricity. We will continue to refine
our technologies so that 8K can be used to increase safety andefficiency with respect to the huge amounts of infrastructure inthese areas as well.

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