Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=F-Bild-Technik}} {{PSM_Infobox}} F-scan technique FORCETOC ==Introduction== The F-scan is a special ultrasound testing and evaluation method for two-dimensional imaging of the Fourier-transformed amplitudes of a tested specimen volume (see: frequency analysis). As with the C-scan, it is composed of A-Scan Techni..."

2025-12-02T08:35:30Z

Created page with "{{Language_sel|LANG=ger|ARTIKEL=F-Bild-Technik}} {{PSM_Infobox}} <span style="font-size:1.2em;font-weight:bold;">F-scan technique</span> __FORCETOC__ ==Introduction== The F-scan is a special ultrasound testing and evaluation method for two-dimensional imaging of the Fourier-transformed amplitudes of a tested specimen volume (see: frequency analysis). As with the C-scan, it is composed of A-Scan Techni..."

New page

{{Language_sel|LANG=ger|ARTIKEL=F-Bild-Technik}}
{{PSM_Infobox}}
<span style="font-size:1.2em;font-weight:bold;">F-scan technique</span>
__FORCETOC__

==Introduction==

The F-scan is a special [[ultrasound Testing|ultrasound testing]] and evaluation method for two-dimensional imaging of the Fourier-transformed amplitudes of a tested specimen volume (see: [[Frequency Analysis|frequency analysis]]). As with the [[C-Scan Technique|C-scan]], it is composed of [[A-Scan Technique|A-scans]] that have been recorded using a grid of equidistant measuring points. The sum of the recorded amplitudes in the frequency domain is assigned a colour or gray value. This means that each Fourier-transformed [[A-Scan Technique|A-scan]] receives a pixel as a colour or gray value. In the F-scan, these pixels are assembled, and the colour values are graded relative to the scaling of the colour palette used [1, 2]. The evaluation procedures required for the F-scan can thus be performed in the same way as for the C-scan.

==Construction of the F-scan==

Using a manipulator (scanner), the test piece is moved through a [[Ultrasonic Immersion Bath Technique|water bath]] according to the previously specified grid definition. Water is located between the ultrasonic transducer, which acts as a transmitter and receiver ([[Pulse-Echo Ultrasonic Technique|pulse-echo ultrasonic technique]]), and the test piece surface ([[Ultrasonic Transmission Technique|ultrasonic transmission technique]]). The [[HF-Scan|HF-scans]] are recorded at the previously defined raster points.

[[File:F-Scan-Technique-1.jpg|425px]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|HF-scan of a measurement on polypropylene ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PP) using the immersion technique
|}

'''Figure 1''' shows the result of a [[Measure|measurement]] on polypropylene ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PP) with a thickness of 20 mm. While the surface echo reaches 100 % of the amplitude, the rear wall echo only reaches 17 %. This corresponds to a sound level loss of −15 dB and is typical for this [[Plastics|plastic]], which has a specific sound attenuation of 0.38 dB/mm.

[[File:F-Scan-Technique-2.jpg|425px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Fourier transforms of the surface signal from '''Fig. 1'''
|}

The corresponding Fourier transform is formed from a selected echo from the [[HF-Scan|HF-scans]] determined at each raster point ('''Fig. 2'''). The value of the frequency at the amplitude maximum of the Fourier transform is thus determined for the respective echo at each raster point. A matrix with these frequencies is set up according to the raster. The frequency maximum and minimum are assigned to the extrema of the selected colour palette, resulting in a relative assignment of the colour values to the frequency values at the grid points (= the matrix elements), similar to the [[C-Scan Technique|C-scan]].

==Practical relevance of the F-scan==

The F-scan is very important for testing surface-related defects in a [[Plastic Component|component]]. Its special property compared to the volume scan is the layer-by-layer examination of a test piece by evaluating individual defined successive time intervals of the [[HF-Scan|HF-scan]], whereby the frequency changes of the reflection signals are of interest.

'''Figure 3''' shows the F-scan of a test specimen made of polyamide 6 ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PA 6), which reveals defects in the detected test specimen volume. In contrast, these defects could not be detected in a measurement with an amplitude-based [[C-Scan Technique|C-scan]] due to the high sound attenuation. The F-scan allows, for example, air inclusions (see: [[Gas Bubbles|gas bubbles]] and pores) in highly sound-attenuating [[Material & Werkstoff|materials]] to be detected more effectively using this frequency-based evaluation method, thereby extending the range of [[Ultrasound Testing|ultrasound testing]] and its resolution to weak but frequency-sensitive echo signals.

[[File:F-Bild-Technik-3.JPG|400px]]
{|
|- valign="top"
|width="50px"|'''Fig. 3''':
|width="600px"|F-scan of a sintered test specimen made of polyamide 6 ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PA 6)
|}

==See also==

* [[A-Scan Technique|A-scan technique]]
* [[B-Scan Technique|B-scan technique]]
* [[Imaging Ultrasonic Testing|Imaging ultrasonic testing]]
* [[C-Scan Technique|C-scan technique]]
* [[D-Scan Technique|D-scan technique]]
* [[HF-Scan|HF-scan]]
* [[Ultrasound Testing|Ultrasound testing]]

'''References'''

{|
|-valign="top"
|[1]
|Matthies, K., Gohlke, D.: Der Ultraschall-Volumenscan als Werkzeug zur Prüfung komplizierter Geometrien und komplexer Gefüge. DGZfP-Jahrestagung 2007
|-valign="top"
|[2]
|Deutsch, V., Platte, M., Vogt, M.: Ultraschallprüfung – Grundlagen und industrielle Anwendungen. Springer, Berlin Heidelberg (1997), (ISBN 3-540-62072-9; see [[AMK-Büchersammlung|AMK-Library]] under M 45)
|}

[[Category:Acoustic Test Methods_Ultrasonics]]

F-Scan Technique - Revision history