Hide flaws and reveal them!

The crisp, clear images of the OmniScan X3 flaw detector present unambiguous inspection data

When the envelope function is enabled, the Total Focus Mode (TFM) algorithm of the instrument software extracts both the true component of the signal and the theoretical component of the signal, and combines the two before the OmniScan X3 instrument uses the envelope function for detection.

Reconstruction artifacts can be seen on defective signals when envelope is turned off

When the envelope function is turned on, the obtained total focus mode (TFM) reconstructed image is clearer and more vivid, with increased amplitude and no data loss

The first reason is related to detection performance

However, there is a workaround for this

When the envelope function is enabled, a coarser grid resolution setting is used: this Total Focus Mode (TFM) grid has 2.

Typically, in ultrasound inspection, the higher the number of dots per wavelength, the better the resolution and therefore the better the image quality, but the performance of the Total Focus Mode (TFM) envelope turns this concept upside down
.
Even after reducing the resolution and the number of points per wavelength (pts/λ), the envelope function continues to provide high-quality images
.

Effect of Total Focus Mode (TFM) Envelope on Amplitude Fidelity and Grid Resolution

The number of points per wavelength (pts/λ) is an important factor in maintaining acceptable amplitude fidelity values
.
Inspection specifications, such as ASME's new Total Focus Mode (TFM) appendix, require that amplitude fidelity values ​​remain stable at about 2 dB or less
.

If envelopes are not used, a ratio of about 7 pts/λ is required to maintain the 2 dB amplitude fidelity value that enables fine grid resolution
.
However, if the envelope function is enabled, the safety ratio required to ensure that the minimum amplitude fidelity value at which the defect can be detected can be reduced to 2 pts/λ
.
However, to consistently obtain high-quality images related to the envelope, a ratio of about 3 pts/λ is usually required
.

When the envelope function is enabled, a coarser grid resolution can be used because the processing algorithm uses both the actual signal and the theoretical signal for its calculations
.
More detailed information can be found by reading the application note: "Method for Determining Total Focus Mode (TFM) Grid Resolution Using Amplitude Fidelity for the OmniScan X3 Flaw Detector" .

With experience, the operator will have more confidence in the all-focus mode envelope function 

With a small adjustment to the raster resolution, the envelope function can be used, and a higher acquisition rate can be obtained
.
However, there is still one hurdle to overcome, and this is a second reason why some inspectors may not choose to use the envelope function: Total Focus Mode (TFM) is a relatively new technology, and they may not be familiar with it yet.
Too familiar, and the envelope function is a newer technology developed after TFM
.
Operators may need to try the envelope function several times before finally believing in the power of the envelope function
.

It is important to remember that the envelope function does not lose data information
.
Instead, the signal response from the defect is enhanced thanks to the reconstruction effect of the envelope function
.

Total Focus Mode (TFM) envelope function provides consistently sharper defect images 

In our own experimental inspections, it was once again demonstrated that the envelope function can enhance the effect of total focus mode (TFM) images: the defects in the image are more clearly defined
.
This capability has significant advantages for detecting tiny defects that are often difficult to find and characterize by standard phased array techniques, such as High Temperature Hydrogen-Induced Defects (HTHA)
.

Example of an all-in-focus image of an early high-temperature hydrogen-induced defect captured by the OmniScan X3 flaw detector with envelope processing enabled

High-temperature hydrogen-induced defects (HTHA) are highly hidden corrosion defects that may gradually develop in steel materials exposed to hydrogen at high temperatures, such as tanks or pipes in oil refineries or petrochemical plants
.
Using Total Focus Mode (TFM) imaging, inspectors can confirm that their suspicions of early high-temperature hydrogen-induced defects are correct, so they can take action to avoid failures
.

As with most innovative technologies, the image speaks, and seeing is believing, is also the goal of the all-focus approach envelope function

Using the envelope function, inspectors can see a dynamic envelope image of the actual workpiece being tested, and the empirical inspection data presented in the image cannot be questioned
.
People can only reassure people by seeing it with their own eyes, which is the driving force behind many extraordinary innovations
.

——Olympus Industrial Solutions——

Provide you with industrial endoscopes, non-destructive testing instruments, industrial microscopes, spectrometers and other equipment and accessories
.

Toll Free Hotline: 400-969-0456

Official website: arial="arial" border-box="border-box" box-sizing:="box-sizing:" break-word="break-word" em="em" gb="gb" helvetica="helvetica" hiragino="hiragino" important="important" microsoft="microsoft" neue="neue" normal="normal" pingfang="pingfang" px="px" rgb="rgb" sans="sans" sans-serif="sans-serif" sc="sc" > Email: SSBD.
Marketing@olympus.
com.
cn‍

↓Long press the QR code to follow↓