DOCUMENTS
Stereoscopic Diameter Gauge
- High accuracy and high speed
- Easy installation and maintenance
- Ethernet and Profibus-DP connectivity
DigiScan XD4500
The Stereoscopic Diameter Gauge DigiScan XD4500, designed for installation in tube mills and forging plants is the state-of-the-art technology for measuring diameter of hot products up to 4 m. The stereoscopic arrangement permits high on-line accuracy, even if the product is not at a fixed position. The stereoscopic principle permits to measure the distance between the gauge and the product. This measurement is then used to precisely calculate the real diameter.
Main features
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- Two digital CCD cameras with 4096 pixels each and high-quality multi-lens optics, mounted on a precision optical bed in stereoscopic vision Operating principle The core of the DigiScan XD4500 consists of proprietary software operating on a high performance frame grabber and two 4096 pixel CCD (Charge Coupled Device) high performance digital cameras. DELTA Stereoscopic Diameter Gauge employs an advanced digital edge detection process that captures the digitized camera data. Software routines running on the high speed embedded processor perform sub-pixel edge determination in two dimensional space. The camera data is filtered using a high-speed Infinite Impulse Response (IIR) digital filter. Sub-pixel edge locations are then determined based on the second derivative of the pixel data. With two sub-pixel edges from each camera, the centre position (Cx, Cy) and the diameter of the material are calculated using geometric triangulation. These trigonometric functions allow very accurate measurement of the diameter.
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Connectivity
The DigiScan XD4500 with built in Ethernet connection, integrated digital and analogue I/Os has a very flexible communication architecture and can easily be connected into any automation system.
Ethernet connection permits communication with level 2 for exchange of product identification and measurement data.
I/Os (and optional Profibus DP) permit connection to level 1.
The DigiScan has in standard 2 analogue outputs which can be configured (normally set for indication of the diameter and centreline) and 6 digital I/Os.
Software
The DigiScan XD4500 is delivered with a PC software (Windows XP). The communication is established through Ethernet TCP/IP protocol.
This software includes the following features:
- Display of diameter profile along the tube, centreline and gauge status and any other measurements such as edge position.
- Gauge diagnostic,
- Gauge configuration,
- Gauge verification,
- Data logging including recording of all measurements.
The diagnostic function includes: analysis of the actual tube position in space and edge locations, graphical analysis of raw camera line scan data, log functions. The data can be stored and replayed at a later time for analysis.
Calibration
Two-dimensional calibration is performed prior to delivery on a precisely positioned calibration fixture at several discrete reference heights. Calibration is accomplished by collecting camera pixel data at these reference heights and then generating coefficients that map the pixel locations to spatial locations at any height within the calibrated range. A successful calibration will therefore: Normalize for any lens distortion effects and establish the system triangulation compensation to any pass line and material thickness variations.
The gauge is delivered calibrated in our factory. The installation position is not critical as the stereoscopic cameras will compensate for any variation in the distance between the tube and the gauge.
The DigiScan XD4500 is shipped with a certified mask with several slots simulating different diameters and a verification software.