GB/T 36015-2018Non-destructive testing instruments—Performance and testintg rules of industrial digital X-ray imaging system (English PDF)

3.7 High voltage ripple coefficient

Peak value of alternating components in high voltage generated by X-ray system.

NOTE: Ripple coefficient = ripple voltage/output voltage.

3.8 System total unsharpness

NOTE: The smaller the unsharpness is, the clearer the details are, which is expressed in mm.

3.9 Image SNR

Ratio of statistical standard deviations of average signals to signals of the zone in some zone of test images.

3.10 Sensitivity of IQI

Percentage of the diameter of IQI identifiable finest wire to the thickness of object to be tested in the central zone of images.

4.1 Photovoltaic conversion

The process in which X-ray is received by a receiving-conversion device and converted into electrical signals.

4.2 Analog-digital conversion

The process in which analog signals are converted into digital signals.

5.1 General

5.3.3

System image grade shall not be lower than 256.

5.4 Computer systems

5.4.1 Computer configuration

Desktop computers, image workstations or notebook computers are preferably used; for poor working environment, industrial personal computers can be used.

5.4.2 CRT monitor

CRT monitors are preferably used, whose dot pitch is not greater than 0.26 mm and refresh rate is greater than 75 Hz.

5.4.3 Image storage

5.4.3.1 Stored digital images shall include work piece number, image name, transmission thickness, technological parameter, date and other effective information and shall not be modified. Necessary information can be displayed along with images.

5.4.3.2 Images shall not be modified or deleted after storage; storage devices for a long term storage are preferably used.

5.4.3.3 Original, unprocessed data shall be stored in image storage.

5.4.4 Image processing software

5.4.4.1 It shall meet the technical standards specified for products to be tested.

5.4.4.2 It shall include image acquisition modules, image processing modules and image display modules; other functional modules such as image auxiliary evaluation and database management, are recommended to be added as required by actual test.

5.4.4.3 It shall have image geometrical dimensions and measurement and defect positioning functions.

5.5 System requirements

5.5.1 Resolution

The system resolution of X-ray digital imaging devices shall be better than 1.5 LP/mm; the resolution test method shall be as specified in Annex A.

5.5.2 Sensitivity of IQI

The sensitivity of IQI shall be better than 2.0%; the IQI sensitivity test method shall be as specified in Annex B.

6.4.1 Geometrical amplification

In accordance with the relationships between the relative positions of X-ray generator (source), work piece to be tested and X-ray receiving-conversion device, see equation (1) for the geometrical amplification factor: where, M - the geometrical amplification factor;

L1 - the distance from the focus of X-ray generator to the surface of work piece to be tested;

L2 - the distance from the surface of work piece to be tested to the surface of ray receiving-conversion device.

6.4.2 Selection of amplification factor M

For the optimum amplification factor see equation (2): where, Mopt - the optimum amplification factor;

U - the inherent system unsharpness;

d - the focus size.

6.5 Image quality

6.5.1 Test method

Use metal wire IQI to test image quality.

6.5.2 Sensitivity of IQI

Use the minimum identifiable wire diameter of geometric metal wire IQI to evaluate test sensitivity.

6.5.3 Improving image quality

The method for improvement of image quality include: […]

8.1 Marking

Nameplate shall include:

a) type specifications and product name;

b) major technical parameters;

c) manufacturer name, address and trademark;

d) data and number of production;

e) mark of conformity.

8.2 Packaging

8.2.1 Systems shall be provided with composite packaging, as specified in GB/T 13384.

8.2.2 The words and marks on the wall of packaging boxes shall be legible and indelible which shall not be blurred because of rubbing in handling or rain. The content shall include at least:

a) manufacturer name;

b) product name and type specifications;

c) name and address of receiver, and name and address of shipper;

d) packaging volume (L×W×H);

e) packaging boxes shall be marked with the words such as "upward", "fragile", "keep dry" and "do not roll", or the words or symbols for packaging, transportation and storage specified in GB/T 191;

f) number and name of product standards implemented.

8.2.3 Packaging boxes shall enclose the following accompanying documents:

a) packing list;

b) conformity certificate;

c) instruction manual;

d) list of accessory (spare) parts attached.

A.3 Test method for system resolution of X-ray digital imaging devices

Place an X-ray test image resolution tester closely against the surface center area of the input screen of the X-ray detector, with grid bars forming an angle of 90° with the horizontal position; carry out transillumination under the following test conditions:

a) the distance from the focus of X-ray tube to the surface of X-ray detector input screen is not less than 500 mm;

b) select appropriate tube voltage and tube current to ensure images have appropriate degrees of brightness and contrast.

A.4 Determination of X-ray digital imaging system resolution and system unsharpness

A.4.1 Determination of X-ray digital imaging system resolution

On the display screen, observe the image of X-ray test image resolution tester; observe a line pair where grid bars just start to separate, and then the value corresponding to the line pair is system resolution.

A.4.2 Determination of system unsharpness

On the display screen, observe the image of X-ray test image resolution tester; observe a line pair where grid bars just start to coincide, and then the grid bar width corresponding to the line pair is the inherent system unsharpness. […]