Optical metrology · Software development · Image processing

Optical metrology · Software development · Image processing

  • Welcome

    • Company

  • News

  • Exhibitions

  • Products

    • Optics Test Equipment

    • measuring systems for beverage can manufacture

    • drawing die and wire measurement

    • Meters for Contact angle and surface tension

    • Semiconductor technology, Micro scriber

    • Measurement of Straightness, Flatness, positioning uncertainty of round tables

    • Measuring microscopes, Image processing

    • Flatness, Bow, Warp, curvature, glass thickness

    • Measuring systems for night vision systems

  • Product videos

  • Software Download

    • COMEF



    • RTM


    • Teamviewer

  • Contact

    • ISO 9001 Certificate

    • Representatives

    • privacy policy

Products > Meters for Contact angle and surface tension > SURFTENS PD - Measurement of surface tenison using the Pendant Drop method

SURFTENS PD is an image processing software for measurement of surface tension of liquids by pendant drop method.
By help of drop shape analysis the surface tension is calculated, using the form parameters of the pendant drop.
SURFTENS PD is used in connection with OEG equipment, but also available as standalone solution for applications of customer.


Get in touch >

Technical background




The Knowledge of surface tension is essential for many industries. It allows predictions about wetting and adhesion behaviour. The companies who benefit from the development work e.g. in the paint, lacquer and ink industry, the semiconductor and display industry, detergent industry, water supply and distribution, the cosmetic, pharmaceutical and dental industry and in biological engineering or they produce textiles, plastics and glues, films or optical equipment. The consistent use of measurement of the surface tension facilitates specific development of products and optimization of the requested physical and chemical properties.

Comfortable Windows software

For determination of the surface tension by the pendant drop method the 32 Bit Software SURFTENS 4.2 PD is used. This program, descended from the COMEF family, features comfortable functions for representation the drop and measurement of the surface tension. The generation of the drop is carried out by a device of the SURFTENS family. For the determination of the surface tension a drop shape analysis is made. The measured parameters are drawn in the video image. Through an iterative procedure a theoretical drop profile is fitted to the experimental drop profile. The required calibration of the system is carried out with different subpixelalgorithm that guarantee highest precision. Calibration is needed everytime the magnification, or even the position of the needle, is changed. Notice: the error in surface tension will be twice the error in calibration. The densities of the used test media and the surrounding media are parameters that are essential for exact computation of the surface tension. They have to be put in by the user. The program provides an extra window for entering the densities. The settings used last are remembered by the program. The collected data can be analysed in standard protocols, that provide statistic analyses as mean or standard deviation. The user has also the possibility to choose user defined protocols that are freely configurable. Even a formula editor is integrated. The measurement results can also be stored from the standard protocol into ASCII files and can therefore be further processed in any possible way.

Technical parameters

Windows image processing software for determination of the surface tension of liquids by the pendant drop method with:

live video representation in connection with OEG-frame-grabber for analogue standard video CCD-cameras

live video representation for special Megapixel-Digital cameras

Image acquisition from all sources with Twain-Interface

representation of any digital pictures up to (4096 x 4096) pixels

picture scaling (with conversion of the calibration values)

automatic computation of the optimum scaling factor for a screen-filling representation

calibration with subpixel algorithm

comfortable picture inscription with texts and rulers to scale (also at the scaled picture), measuring values, measuring markers,…

saving / printout of BMP- and JPEG-format - picture

picture in intermediate file copy/insert from intermediate file

hair cross insertion

grid insertion

Statistics and measurement error analysis

Analysis optional in standard protocols or in freely configurable measurement protocols

Data export as ASCII-File

Input of densities of the used media


Image sources

USB 2.0-Camera with up to 1,3 MPixel, UI-series* (live video representation)

Frame Grabber OEG (live video representation)

stored pictures in the BMP- and JPEG format up to 16 MB (4096 x of 4096 pixels)

all devices with TWAIN interface (image acquisition under COMEF software)


Measuring functions:

Measurement of the surface tension of liquids according to the pendant drop method


Operating system:

Windows 2000/XP/7