Tuesday, July 12, 2016

A New Parallel VLSI Architecture for Real-time Electrical Capacitance Tomography

A New Parallel VLSI Architecture for Real-time Electrical Capacitance Tomography
This paper presents a fixed-point reconfigurable parallel VLSI hardware architecture for real-time Electrical Capacitance Tomography (ECT). Another FPGA module performs the inverse steps of the tomography algorithm. A dual port built-in memory banks store the sensitivity matrix, the actual value of the capacitances, and the actual image. A two dimensional (2D) core multiprocessing elements (PE) engine intercommunicates with these memory banks via parallel buses. We are focus only on the FPGA module because the design is decide the power consumption and cost. The proposed architecture of this paper analysis the logic size, area and power consumption using Xilinx 14.2.

Use color image for the processing .i.e., RGB image.

Electrical Capacitance Tomography (ECT) is an effective technique to measure a process non-intrusively by reconstructing the 2D or 3D dielectric distribution of its different constituencies. This makes ECT a good candidate for several industrial applications such as two-phase flow monitoring, quality control in manufacturing industry, and corrosion detection. In the last few years, several ECT systems have already been suggested.
Most of them used a desktop computer as a main processing unit and focused their research mainly on improving the accuracy and execution time of the algorithms on general purpose computers. Nevertheless, the tremendous computation complexity of the tomography algorithms let them to be executed still relatively slowly (in few seconds order), preventing them to sustain real-time applications. Hence, only few research works have been done on designing dedicated hardware architectures for ECT tomography using either DSP processor or FPGA technology. In, a dedicated architecture based on the DSP processor, TMS320C6701; operating at 133 MHz was suggested for the image reconstruction algorithm. The system consists of 12 electrodes and claimed to be able to achieve the image reconstruction of images of 480 pixels within a throughput of 135 frames/s, when using the Linear Back Project (LBP) algorithm. Similarly, in a TMS3206416 processor was used in LBP-based ECT system with 16 electrodes to achieve a throughput of 200 frames/s.
Other works were also suggested for FPGA-based image reconstruction targeting other tomography modalities such as computed tomography (CT) and Single-Photon Emission Computed Tomography (SPECT).FPGA-based Electrical Impendence Tomography (EIT) system comprises several FPGA-based Impedance Measurement Modules (IMM) comprising independent current sources and voltmeters intercommunicating through a reconfigurable FPGA-based Intra-network controller.

·        It’s only for gray scale based process
·        Performance is less

This constitutes the core engine of our ECT system since it performs the image reconstruction task for color images (i.e. RGB format images). Figure 4 shows the derailed VLSI architecture. It is modular and divided into four main modules,
1.     A parallel processing module
2.     A data variable input/output memories modules
3.     A sequencer and memory controller modules
4.     Post processing modules
We are only focus on processing unit for this proposed system with RGB format image processing. The parallel processing module is parallel like architecture which is composed of several similar adder/multiplier processing units. Each of these units is scalable and consists of three pipelined stages: Decomposition stages, Basic unit operation stages, Composition stages. Figure shows these stages at both matrix and bit-levels.
Figure 4: image reconstruction implementation block diagram on FPGA
1.1.1    Decomposition stages:
For the three afro-mentioned algorithms, the matrix decomposition consists to divide the two matrices to multiply into regular square blocks (q * q) which are then simultaneously processed by the parallel processing units using bit decomposition techniques.
The basic unit operator stage in matrix level covers decomposition stage in bit level, basic unit operation stages in bit level; add composition stage in bit level as described in below. Figure 6 shows the overall operations in basic unit operation stage. Port A and port B are the input ports of the k-processing unit.

Figure 6: Overall architecture with three main units. Figure is illustrated with the number of basic operators, N basic, which equal to 4.

         Increase the performance

·        Modelsim
·        Xilinx ISE