Imaging of a distinctive large bubble in gas–water flow based on a size projection algorithm

Li, Kun; Wang, Qiang; Wang, Mi; Han, Yan

doi:10.1088/1361-6501/ab16b0

Cited by 6 publications

(3 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a fast, nonradiation, nonintrusive, and low-cost imaging technique, electrical resistance tomography (ERT) [1] has been developed for visualizing the internal conductivity distribution of industrial processes, by providing 2D/3D images. ERT has been widely used for chemical [2], food processing [3], biology [4], geology [5], and other industrial applications [6]. In ERT, usually a current is injected to a pair of electrodes and the boundary voltages are measured from other pairs of electrodes [7].…”

Section: Introductionmentioning

confidence: 99%

A New Iterative Algorithm Based on Correction of Sensitivity Matrix for Electrical Resistance Tomography

Chen

Han

Yang³

et al. 2019

Mathematical Problems in Engineering

Self Cite

View full text Add to dashboard Cite

Electrical resistance tomography (ERT) is used to reconstruct the resistance/conductivity distribution. Usually, a uniform distribution is assumed as the initial condition to obtain a generic sensitivity matrix, which may be very different from a theoretical sensitivity matrix, resulting in a large error. The aim of this study is to analyse the difference between a generalized sensitivity matrix and a theoretical sensitivity matrix and to improve image reconstruction. The effect of the generic sensitivity matrix and theoretical sensitivity matrix on image reconstruction is analyzed. The error caused by the use of the generic sensitivity matrix is estimated. To reduce the error, an improved iterative image reconstruction algorithm is proposed, which is based on calculation of the error between the generic sensitivity matrix and the theoretical sensitivity matrix, and a correction coefficient with a penalty. During the iterative process, the resistivity distribution and sensitivity matrix are alternatively corrected. Simulation and experimental results show that the proposed algorithm can improve the quality of images, e.g., of two-phase distributions.

show abstract

Section: Introductionmentioning

confidence: 99%

A New Iterative Algorithm Based on Correction of Sensitivity Matrix for Electrical Resistance Tomography

Chen

Han

Yang³

et al. 2019

Mathematical Problems in Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…The threshold value used for classifying small bubbles and large bubbles in the bubble lookup table needs to be studied for the theoretical support, e.g. determining the value with an inverse method [33]. Since the visual results are dependent on the quality of input data, i.e.…”

Section: Discussionmentioning

confidence: 99%

Bubble mapping: three-dimensional visualisation of gas–liquid flow regimes using electrical tomography

Wang

Jia

Wang

2019

Meas. Sci. Technol.

View full text Add to dashboard Cite

It is well known that electrical tomography is capable of 'seeing' through opaque pipe walls and flow media. However, due to the relatively low spatial resolution, electrical tomograms are ineffective on visualisation of small bubbles or sharp interfaces between large bubbles and the liquid. These limitations give rise to ambiguity in human and/or machine perception of flow dynamics from presenting bubble cluster and blurry boundaries of large bubbles in faint colour or grey. In this paper, a binary approach, called bubble mapping, is proposed to enhance the visibility of flow regime in gas-liquid pipeline flows. With the input gas concentration tomograms reconstructed by an electrical tomography, the method takes the major visual characteristics of typical flow regimes in common recognition as a prior knowledge and replaces the conventional colour mapping with a number of bubbles and their mergence with a thresholding value. With this approach, a stack of cross-sectional tomograms by electrical tomography is transformed and displayed as a collection of individual gas bubbles. The transformation is done with the help of a lookup table indexed by bubble size and an enhanced isosurface algorithm for vivid three-dimensional visualisation. This new approach has been applied to a gas-in-water flow rig and its performance is compared with photo images taken by a high-speed camera. Reasonable agreements have been obtained for common flow regimes including bubbly flow, stratified flow, plug flow, slug flow and annular flow in horizontal pipe and bubbly flow, slug flow and annular flow in vertical pipe. Results evidence the method can provide a photorealistic flow visualisation and therefore enhance the visibility of electrical tomograms for visual identification of flow regime, particularly for opaque media in industrial flows.

show abstract

“…Second, segmentation or interpolation is used to narrow the interval. The Golden-Section algorithm is adopted here, as in [21]- [23], the golden ratio 𝜆𝜆 =…”

Section: Solving Thread Profile Projection Curve Based On Linear Searchmentioning

confidence: 99%

A Novel Non-Contact Measurement Method of Ball Screw Thread Profile Detection Based on Machine Vision

Miao

Wang

Chen

et al. 2023

Measurement Science Review

View full text Add to dashboard Cite

The transmission accuracy of the ball screw depends on the processing quality of the thread profile. Traditional detection method of thread profile is complicated and inefficient. When shooting the thread profile of the ball screw in the normal section, the camera axis must be tilted to the lead angle, and adjustment errors are easily introduced from both the front view and the top view. When shooting in the axial section, the spiral lines block each other, so the actual thread profile cannot be captured for detection. In order to solve the above problems, a thread profile detection method is proposed: the theoretical equation of the ball screw thread profile in the axial section is derived based on the theoretical thread profile in the normal section, and the theoretical equation of the thread profile projection curve in the axial section is solved based on helix analysis, and the differential equation between them is obtained; then, the theoretical correction value of the thread profile projection curve is obtained by Linear Search to find the boundary value; the actual thread profile in both axial section and normal section is finally obtained with the theoretical correction value, which can support accurate measurement and detection of the key parameters of the thread profile. Experiments show that the proposed method can effectively improve the accuracy of the ball screw thread profile detection.

show abstract

Imaging of a distinctive large bubble in gas–water flow based on a size projection algorithm

Cited by 6 publications

References 30 publications

A New Iterative Algorithm Based on Correction of Sensitivity Matrix for Electrical Resistance Tomography

A New Iterative Algorithm Based on Correction of Sensitivity Matrix for Electrical Resistance Tomography

Bubble mapping: three-dimensional visualisation of gas–liquid flow regimes using electrical tomography

A Novel Non-Contact Measurement Method of Ball Screw Thread Profile Detection Based on Machine Vision

Contact Info

Product

Resources

About