Design and Simulation of Array Cells of Mixed Sensor Processors for Intensity Transformation and Analog-Digital Coding in Machine Vision

Abstract

The urgent need to create video sensors and processors for parallel (simultaneous by pixel) image processing with advanced functionality and multichannel picture outputs is shown in the chapter. We consider perspective spheres and areas of application of such sensor processors, in particular, for hardware high-performance architectures of neural networks, convolutional neural structures, parallel matrix-matrix multipliers, and special processor systems. We show and analyze the theoretical foundations, the mathematical apparatus of the matrix and continuous logic, and their basic operations, show their functional completeness, and evaluate their advantages and prospects for application in the design of biologically inspired devices and systems for processing and analysis of array signals. We show that some functions of continuous logic, including operations of normalized equivalence of vector and matrix signals, the operation of a limited difference in continuous logic, are a powerful basis for designing improved smart micro-cells for analog transformations and analog-digital encodings. In the next sections of the chapter, we consider in more detail the design and modeling aspects of such micro-basic cells and continuously logical high-speed ADCs based on them. The picture-type ADC consists of an array of parallel operating channels, each of which is a basic microcell or a set of them. The basic microcell of a 2D ADC structure consists of several digital-analog cells (DC), which is made on 15–35 CMOS transistors. For an iterative type ADC, only one DC cell is needed, which is DC-(G), and it additionally contains a sample and hold device (SHD). In this case, the entire base microcell can be performed on just 35 CMOS transistors. A single ADC channel cell with iteration has a serial-parallel output code. For a non-iterative-type ADC, its base microcell may consist of such a quantity of DC, which depends on the digit capacity of the code. To simulate the proposed schemes, we used OrCAD, and the results are presented below. Conversion time with 6–8-bit binary codes or Gray codes and an input photocurrent range of 0.1–24 μA is 20–30 ns at a supply voltage of 1.8–3.3 V. If the maximum input current is 4 μA, then for ADC with iteration, total power consumption was only 50–100 μW. Low power consumption at such a supply voltage and good dynamic characteristics (the digitization frequency even for 1.5 μm CMOS technologies is 40–50 MHz) shows good prospects since the structure of the linear array of ADCs and its microcells is very simple. The conversion frequency can be increased ten times with more advanced CMOS transistors. Thus, the proposed ADC based on CL BC and CM are promising for creating photoelectric structures with matrix operands, digital optoelectronic processors, linear and matrix image processors (IP), and other neural-like structures that are necessary for neural networks and neuro fuzzy controllers. In the chapter, we consider a generalized method of designing devices for nonlinear transformation of the photocurrent intensity using a set of similar basic modified cells and their circuits implemented using traditional CMOS technology. To implement the required nonlinear transformation function, we use the decomposition method. The type of synthesized functions is determined by the choice of suitable parameters, which are specified as constants or as parameters with which you can choose or change the type of nonlinear transformation. In this chapter, we also show the need for different types of nonlinear intensity conversion of photocurrents and different codes (gray, binary) for AD conversion in such parallel sensor devices and systems, especially for implementing various types of activation functions in hardware implementations of neural networks, consider the use of such parallel matrix arrays to create progressive IP and neural networks (NN). The cells offered by us have a low supply voltage of 1.8–3.3 V, low power consumption (microwatts), the conversion time is less than 1 μs, and consist of several dozen transistors. We also consider the cells for the implementation of various neuron activation functions in neural networks and transient nonlinear conversion with characteristics of S-, N-, and λ-types. In conclusion, we make estimates and show the prospects for such approaches to the design of sensor processors.