The operator of a shadow measuring videoscope must be proficient in positioning the videoscope tip for maximum accuracy. Source: Advanced Inspection Technologies Inc.


Over the years there have been many methods of conducting remote visual inspection measurements with the use of a video borescope. Unfortunately, some of these methods are frequently confusing and may lead to inaccurate borescope measurement due to lack of training or improper use. To assist operators in avoiding these pitfalls, here are some quick notes on how to properly use a shadow measuring videoscope. Video borescope shadow measurements require the use of shadow measurement tips, which project a shadow onto a target. To measure the target, the videoscope processor uses triangulation based on the shadow’s location. Shadow measurements can only be taken on a frozen image or on a recalled image that was saved in measurement mode. The operator of a shadow measuring videoscope must be proficient in positioning the videoscope tip for maximum accuracy:

  • The videoscope tip must be as close to the surface as possible while still viewing the entire item to be measured. The shadow will move toward the left of the video display as the videoscope move closer.

  • Videoscope measurements can be made even if the tip is so close that the image is somewhat out of focus, as long as the features are sharp enough to place the cursors accurately. For depth measurements, in particular, the tip needs to be close enough to noticeably break the shadow so that the system can accurately differentiate between the raised and recessed surfaces.

  • The shadow must be straight up and down on the video display. This indicates that the surface is perpendicular to the videoscope objective lens.

  • The shadow must be near and on the same plane as the item to be measured.



    • Rigid Borescopes Used With High-Speed Video

    A common application for a rigid borescope is to be used with a high-speed camera. Rather than coupling the rigid borescope to a standard charge-coupled device (CCD) camera, a high-speed camera can be connected. The combination of a rigid borescope and high-speed video allows live remote visual inspection of machinery, rotating components and other processes where the high-speed video camera could simply not fit.

    Rigid borescopes are available in a variety of lengths, diameters and direction of view to best meet the application. The rigid borescope needs to be long enough to reach the area to be recorded. The largest diameter rigid borescope also should be used for optimal light and image results. Finally, the direction of view needs to be considered: is a straight forward 0-degree view, a 90-degree side view or other offset best to view the area to be inspected.

    Automotive Borescope Applications

    Remote visual inspection (RVI) has many applications within the automotive industry. Automotive borescopes provide solutions by allowing internal inspection of engine castings, cylinder bores, gearboxes, body shells and finished vehicles, from state-of-the-art racing cars to earth moving equipment. Investigation of a variety of problems without teardown is possible with an automotive borescope including checking internal component condition for carbon deposits and wear, pinpointing sources of unwanted noise, identifying corrosion and confirming component failure. Borescopes can be used cost-effectively in automotive applications. Automotive applications include:

  • Clutch – condition and thickness of lining, condition of springs of pressure plate and thrust bearing

  • Engine – valve damage, cylinder inspection, head gaskets and piston top

  • Body and Chassis – inspection of hollow members to detect damage cracks and corrosion

  • Transmission and differential – ring, bevel gear inspection, seals and shaft bearing inspection

    Renal of borescopes, videoscopes, fiberscopes and pipe cameras has become a common method of meeting remote visual inspection needs. In the past, the only option to inspecting a one time or emergency application was to purchase equipment for that one purpose.

    Today a video borescope rental can be delivered overnight or even the same day the inspection is required. The appeal of a videoscope rental is the cost savings and fast turnaround. Remote visual inspection equipment rentals have many benefits for both long and short term requirements.