Learn what a video borescope is, how it works, its role in remote visual inspection, industrial applications, detectable defects, benefits, limitations and NDT use.
What Is a Video Borescope? How It Works, Applications and Inspection Methods
A video borescope is an industrial visual inspection instrument that enables engineers and inspection professionals to examine internal areas that are difficult or impossible to see directly. Using a miniature camera, illumination system and insertion probe, a video borescope displays live images on a monitor and, depending on the system, can capture photographs and record inspection videos for documentation and further assessment.
Video borescopes are widely used for Remote Visual Inspection (RVI) of engines, turbines, pipelines, pressure vessels, heat exchangers, boilers, machinery and other enclosed or hard-to-reach components. RVI allows visual examination from outside the asset when direct access is restricted by geometry, equipment configuration or operating conditions.
What Is a Video Borescope?
A video borescope is a digital inspection device designed to transmit visual information from an inaccessible inspection area to an external display.
Unlike a conventional optical borescope that relies primarily on an optical image path, a modern video borescope uses a camera at or near the end of the insertion probe. The captured image is transmitted electronically to a display, allowing the inspector to observe the inspection area in real time.
Depending on the configuration, an industrial video borescope may include:
Miniature digital camera
Flexible insertion probe
LED illumination
Articulation controls
Integrated display
Image capture
Video recording
Adjustable viewing direction
Measurement capabilities on specialised systems
Inspection data and reporting functions
The exact configuration varies according to the inspection application and instrument design.
How Does a Video Borescope Work?
The operating principle is straightforward: the inspection probe carries the camera and lighting system into an inaccessible area while the inspector views the internal condition from outside.
A typical inspection sequence is:
Access point → Probe insertion → Illumination → Image capture → Live display → Visual assessment → Image/video documentation
The probe is introduced through an existing access point, inspection opening, port or other suitable entry route. The camera captures the internal surface, while integrated lighting illuminates areas that may otherwise remain too dark for reliable visual examination.
For complex inspection paths, an articulating probe can help the operator direct the camera towards specific areas of interest. Modern RVI systems can provide real-time viewing and recording, allowing inspection evidence to be retained for reporting, maintenance planning and comparison during subsequent inspections.
Why Is Video Borescope Inspection Used?
Many industrial components contain internal surfaces that cannot be examined effectively from the outside.
Opening, dismantling or cutting equipment solely to obtain visual access can require significant maintenance effort and may interrupt production. Video borescopes provide an alternative approach where suitable access exists.
They can help inspection teams:
Examine inaccessible internal surfaces
Identify visible abnormalities
Document inspection findings
Reduce unnecessary dismantling
Support maintenance planning
Establish visual evidence of component condition
Compare inspection observations over time
The value of a video borescope therefore extends beyond simply producing an image. It provides a practical method for obtaining visual information from locations that are otherwise difficult to access. Industrial RVI is commonly used across aerospace, power generation, manufacturing, oil and gas and other demanding sectors.
What Can a Video Borescope Inspect?
The application depends on the probe diameter, insertion length, articulation, viewing direction, lighting, environmental conditions and geometry of the component.
Typical inspection applications include:
Turbine Inspection
Video borescopes can provide visual access to turbine components and other internal areas where direct inspection is restricted. Inspection teams may examine surfaces for visible signs of wear, corrosion, deposits, damage or other abnormalities.
Engine Inspection
Engines contain numerous internal areas that require specialised access. Video borescopes can assist with visual examination of combustion areas, cylinders, chambers and other difficult-to-access components.
Pipeline and Pipe Inspection
Flexible inspection probes can be introduced into suitable piping systems to examine internal surfaces for visible conditions such as corrosion, deposits, scaling, blockage, cracks or foreign material.
Heat Exchanger and Boiler Inspection
Internal tubes, passages and related components can contain deposits, corrosion or physical damage that may not be visible through external examination.
Pressure Vessel Inspection
Where suitable access points are available, video inspection can help examine internal surfaces without requiring extensive dismantling.
Industrial Machinery
Gearboxes, pumps, valves, hydraulic systems, castings and other machinery can contain enclosed areas where conventional visual inspection is difficult.
Pro Engineers' industrial borescope portfolio specifically identifies turbines, engines, pipelines, vessels and other hard-to-reach components as key inspection applications.
What Defects Can a Video Borescope Detect?
A video borescope provides visual information, so its ability to identify a defect depends on whether the condition produces a visible indication and whether the camera can obtain a suitable view.
Common visible conditions may include:
Cracks or crack-like indications
Corrosion
Pitting
Erosion
Wear
Deposits
Scaling
Foreign objects
Surface damage
Blockages
Weld-related surface irregularities
Deformation
Material deterioration
For example, during internal pipe inspection, a camera may reveal corrosion, deposits, blockages, weld irregularities or foreign material. However, the appearance of an indication does not necessarily establish its complete nature, depth or structural significance.
Where a visual finding requires further evaluation, another appropriate NDT method may be necessary.
Video Borescope and Remote Visual Inspection (RVI)
Remote Visual Inspection, commonly abbreviated as RVI, is the broader inspection methodology. Video borescopes and videoscopes are among the tools used to perform RVI.
RVI is particularly useful when the inspection location is:
Physically inaccessible
Confined
Located inside machinery
Difficult to observe directly
Located along a curved or obstructed pathway
Unsuitable for conventional direct visual examination
The fundamental purpose is to move the visual observation capability to the inspection location while allowing the operator to remain outside the inspected area.
Therefore:
Video borescope = inspection instrument
RVI = inspection approach/methodology
This distinction is useful when defining inspection procedures and documenting the scope of an examination.
Video Borescope vs Rigid Borescope
Video borescopes and rigid borescopes can both support remote visual inspection, but they are suited to different access conditions.
A rigid borescope uses a straight, inflexible insertion tube and optical system. It is particularly useful where the inspection path provides relatively direct access.
A flexible video borescope uses a flexible insertion tube and digital camera system, allowing inspection through curved or complex pathways. Articulating systems can provide additional control over the camera direction.
Characteristic | Rigid Borescope | Video Borescope |
Probe | Rigid | Flexible |
Access | Generally straight | Straight and curved pathways |
Image system | Optical | Digital camera |
Articulation | Generally limited or unavailable | Available on applicable systems |
Live digital display | System dependent | Typical |
Video recording | System dependent | Common |
Complex internal geometry | More limited | Generally more adaptable |
The appropriate technology depends on the inspection geometry rather than one technology being universally superior. Pro Engineers' existing rigid-versus-flexible guide provides a more detailed comparison of these inspection approaches.
Video Borescope vs Conventional Visual Inspection
Conventional visual inspection normally requires a direct line of sight to the surface being examined.
A video borescope changes the inspection geometry by placing the camera inside or close to the area being examined.
This makes video borescope inspection particularly useful where:
Direct visual access is possible → conventional visual inspection may be sufficient
Direct access is restricted → RVI using a borescope or videoscope may be appropriate
The method does not eliminate the need for engineering judgement. The inspector must still determine whether the available view is adequate, whether the observed condition can be characterised visually and whether additional inspection techniques are required.
Video Borescope Inspection in NDT
Visual Testing (VT) is an established non-destructive testing approach, and remote visual inspection extends visual examination into areas that cannot be conveniently observed directly.
A video borescope can therefore form part of an NDT inspection programme where the inspection objective is to identify and document visible conditions.
However, video inspection has limitations. It generally cannot determine every internal or subsurface condition. For example, an indication that is not visually apparent may require ultrasonic testing, radiography, magnetic particle testing, penetrant testing or another appropriate technique depending on the material and inspection objective.
This is why video borescope inspection is often most effective as part of a broader inspection strategy, rather than as a universal replacement for other NDT methods.
Applications Across Industrial Sectors
Video borescopes are used across industries where internal access is limited.
Aerospace and Aviation
Engine and turbine components contain complex internal geometries where RVI can provide valuable visual information during maintenance and inspection activities.
Oil and Gas
Process piping, valves, pressure vessels, compressors and other equipment can contain inaccessible internal areas requiring inspection.
Power Generation
Turbines, boilers, condensers, heat exchangers and associated equipment may require internal visual examination during maintenance programmes.
Automotive Manufacturing
Engine components, cylinders, castings, fuel systems and machined parts can require internal visual examination.
Pharmaceutical Manufacturing
Process piping, vessels, reactors and hygienic systems may require internal inspection where access is restricted and visual condition assessment is necessary.
Heavy Engineering
Fabricated components, machinery, castings, weldments and hydraulic systems can benefit from remote visual access.
These applications align with the industries and inspection environments currently covered by Pro Engineers' industrial borescope portfolio.
Role of Video Borescopes in Preventive and Predictive Maintenance
A video borescope can support maintenance teams by providing visual evidence of equipment condition without requiring extensive dismantling.
During periodic inspections, recorded images can help maintenance personnel document observations and compare conditions over time where inspection procedures and equipment configuration permit consistent examination.
For example, an inspection programme may identify:
Normal condition → Early visible deterioration → Developing defect → Maintenance intervention
This approach can support condition-based maintenance decisions, but the inspection findings should always be interpreted according to the equipment, applicable procedures, engineering criteria and severity of the observed condition.
What Does a Video Borescope Inspection Produce?
Depending on the equipment configuration, a video borescope inspection may produce:
Live inspection images
Still photographs
Recorded video
Defect documentation
Inspection observations
Measurement data on applicable systems
Inspection reports
Documentation is particularly valuable when inspection findings need to be reviewed by maintenance, engineering or quality teams after the physical inspection has been completed.
Advanced systems may also provide specialised capabilities such as 3D measurement. Pro Engineers' Pro-DSV-PRO, for example, is positioned for three-dimensional measurement and defect sizing in addition to visual inspection.
Limitations of Video Borescope Inspection
Video borescopes are powerful visual inspection tools, but they have practical limitations.
Limited Access
The probe must physically reach the area of interest through a suitable access route.
Restricted Field of View
A camera may not provide visibility of every surface within a component, particularly where geometry is highly complex.
Surface Visibility
The ability to identify an indication depends on lighting, camera position, surface condition, resolution and the nature of the condition.
Visual Evidence Has Limits
A visible indication may require additional investigation to determine its depth, extent, material significance or structural impact.
Environmental Conditions
Temperature, contamination, moisture, chemicals and other operating conditions must be considered when selecting an inspection system.
Consequently, the inspection procedure should define the equipment requirements, access conditions, examination area and acceptance criteria before inspection begins.
A Typical Video Borescope Inspection Workflow
A structured inspection can follow these stages:
1. Define the Inspection Objective
Determine what component, area or condition needs to be examined.
2. Identify the Access Point
Determine the probe's access route to the target inspection location.
3. Assess the Inspection Geometry
Determine whether the path is straight, curved, narrow or obstructed.
4. Select the Appropriate Probe
Consider probe diameter, insertion length, articulation and viewing requirements.
5. Establish Adequate Illumination
Ensure the inspection area can be illuminated sufficiently for reliable visual observation.
6. Perform the Examination
Navigate the probe systematically and inspect the defined areas.
7. Document Findings
Capture photographs, videos and observations where required.
8. Evaluate Indications
Determine whether an observed condition can be adequately assessed visually or requires additional NDT.
9. Record the Inspection
Maintain appropriate inspection records for maintenance, quality assurance and future reference.
How Video Borescope Technology Is Evolving
Modern video borescopes are developing beyond basic image transmission.
Depending on the system, advanced capabilities can include:
High-definition digital imaging
Improved illumination
Multi-directional articulation
Image and video recording
UV inspection
Infrared imaging
3D measurement
Defect sizing
Digital reporting
Data management
For example, Pro Engineers offers specialised industrial borescope configurations that include UV/IR imaging and 3D measurement alongside conventional high-resolution visual inspection.
These capabilities do not change the fundamental purpose of a video borescope: to provide reliable visual access to areas that are difficult to inspect directly. Instead, they expand the amount and type of information that can be obtained during an inspection.
Conclusion
A video borescope provides engineers with a practical means of obtaining visual access to internal and difficult-to-reach areas without relying solely on conventional direct examination. By combining a miniature camera, illumination, insertion probe and external display, it supports Remote Visual Inspection across a wide range of industrial applications.
Its value is particularly evident when inspecting turbines, engines, pipelines, vessels, heat exchangers, boilers and complex machinery where access is restricted.
However, video borescope inspection should be understood as a visual examination technology, not a universal substitute for every NDT method. The most effective inspection programme uses the appropriate technique for the material, component, defect type, accessibility and inspection objective.
For industrial inspection teams, understanding how video borescopes work, where they are applicable and what their limitations are is essential for obtaining useful visual evidence and making informed maintenance and inspection decisions.