The Pixact process measurement technology is based on the direct optical imaging of process suspensions combined with computational image analysis to retrieve desired measurement information.
Our measurement systems are built following a modular concept. The imaging hardware, data analysis algorithms, operator view, reporting of results, installation and integration to factory automation can be tailored according to the customer's needs. The key features of the Pixact process monitoring technology are presented below.
Direct optical imaging has two major benefits over other techniques used for online particle diagnostics (including bubbles, droplets, etc.). First, direct imaging provides visual information on the process. In many cases, this information gives skilled operators and development staff a quick overview of the state of the process as well as the first indication of potential disturbances in the process.
The second advantage of direct imaging is related to the two-dimensional nature of the data. Compared to other optical techniques, such as laser diffraction and dynamic light scattering, direct imaging is able to capture the morphology and other visual properties of the particles, such as color. Thus, even the shape of complex agglomerates can be measured without the assumption of sphericity or other simplifications. Based on the size, shape and color measured for each object, the objects can be classified and the statistics can be computed separately for each particle class.
The Pixact Process Monitoring concept consists of four main elements tailored to the customer's needs. In addition to the high flexibility in adjusting the system, the modular approach enables the easy extension of the system in the future.
The type and characteristics of the process equipment in which the measurements will be conducted determine the requirements for the installation of the imaging components. Pixact offers three default configurations for varying process applications.
A periscope type design for installation on closed reactors and tanks. Available in many flange sizes starting from DN25. The probe length can vary between 50 - 1500 mm depending on the flange size and other installation requirements.
A flow-through cuvette for in-line installation on process and sampling lines. Available in several flange sizes: DN6, DN25 and DN50 (other sizes on request).
A submersible probe design for installation in open tanks, such as flotation cells. Adjustable optical path. Standard operating depth 0 - 5 m.
The imaging hardware consists of a camera, illumination and the Pixsync unit for power supply and the synchronization of the system.
Our selection of high-resolution and extremely sensitive digital cameras combined with powerful controllable illumination units guarantees superior image quality even in the most challenging process conditions.
The imaging setup depends on the process conditions and the details of the measurement task. One of the principal choices is made between back and front illumination. Other essential imaging parameters that need to be determined include optical magnification, depth-of-focus and the wavelength and type of illumination (telecentric vs. diffuse).
Image analysis hardware and software
The core of the measurement system is the Pixstation main unit running the Pixact software. In essence, the Pixstation is a high-performance industrial PC equipped with a modular I/O and database functionality. The system is built in an IP67-rated stainless steel cabinet, which can be installed next to the measurement location or in the automation room. The Pixstation main unit is available in several performance classes depending on the requirements of the analysis.
The image data acquired with the process imaging techniques contains a huge amount of information. In-house developed image analysis algorithms are used to detect objects in the image, classify them and measure their dimensional and morphological parameters, such as diameter, orientation, roundness, surface roughness and fractal dimension. (Here "object" is used to refer to all kind of particles, droplets, bubbles, etc.)
The Pixact team has extensive experience in developing robust high performance image analysis techniques for multiphase flow image data.
User interface / operator view
The Pixact software provides a live view of the process. A dedicated monitor can be placed in the control room or the image stream can be accessed remotely over a LAN connection. The live view provides valuable information for the operators.
The measurement information received from the image analysis is also shown to the operator. Trends, histograms and tabulated statistics are included in the user interface.
Automation connection and results reporting
The Pixact software communicates with the factory automation via the Pixstation I/O-modules. The measurement results can be transmitted to the automation in a wide range of protocols, including analog signals (mA, V) and fieldbus protocols (ProfiBus, Ethernet…).
The Pixact software also includes several data export interfaces, such as Microsoft Excel reports and ASCII text files.
Demonstration of the Pixact software
Imaging components >
Image analysis >
User interface & I/O >
(C) Pixact Ltd, 2017
tel.: +358 (0)10 439 2400 email: firstname.lastname@example.org