Design of flower counter based on CMOS image sensor

Abstract: The structural module and working mode of the new CMOS image sensor ME1010 are described, and a flower counting system with ME1010 as the core is designed. The hardware and software structure of the system are given, and the hardware and software are simulated and analyzed by computer. The simulation results show that the system can meet the requirements of flower counting operation in the production process of high-count fibers and has practical value.
Keywords: CMOS image sensor; ME1010; Flower counting device

0 Introduction
The defects on fabrics are mainly caused by flower knots on fibers. Flower counting devices are a common equipment in the textile industry. They are mainly used to count (or remove) flower knots on spindles and are the main basis for determining the quality grade of fibers. At present, domestic flower counting devices mainly include capacitive and photoelectric types, which have low accuracy and are difficult to handle high-count fibers. This paper proposes to use CMOS image sensors to perceive fiber flower knots, and its accuracy can reach 0.02mm, which can fully meet the current production needs of high-count fibers.

1 Introduction to ME1010
ME1010 is an easy-to-use integrated image sensor developed by Microne using a patented structure to make it easier to form an integral whole with computer products. Unlike traditional CCD image sensors or some new CMOS image sensor products, the ME1010 image sensor provides extremely low-speed XY address image output for easy connection with a computer or DSP. It provides 352×290 pixels (352×288 of which are effective pixels), an on-chip amplifier and matching ADC circuits.
In addition, a wide range of continuous full-screen electronic shutter function (from 1μs to 255ms) can avoid the need for many optical devices such as apertures and mechanical shutters. This is very attractive for compact and economical products such as directional audio-visual camera components, electronic surveillance, car TV systems, consumer products, high-tech toys, etc.
Its main features are: 12.1μm×12.1μm CMOS pixel element; 352×290 pixel array (effective element: 352×288); on-chip frame buffer based on pixel element; low-speed output of pixel signal according to XY address; on-chip video amplifier; on-chip 8-bit A/D converter; low power consumption (less than 200mW); full-screen electronic shutter with wide range continuous adjustment; built-in black state reference; LCC-48
pin package;
Function:
Pixel array: It consists of 352×290 photosensitive areas, including a series of reference rows and an available 352×288 pixel array.
The state of the control signal "XYSEL" determines the decoding of the nine-bit address (ADO to AD8) corresponding to the X or Y address. The initialization of the photosensitive process is preset by the level of "VRST" to each photosensitive element in the photosensitive area. The initialization of the pixel array can be performed once for the whole screen, or it can be performed row by row through the combined logic state of "PREC", X address decoding output and "G" signal. The generated photosensitive signal can be temporarily stored in the frame buffer. Through the sampling control signal (including the logic synthesis of the "Samp" signal, the X decoding output, and the "SampG" signal), the specified content in this buffer can be read out by the XY address.
During the data reading period, the X address decoding output and the "Sel" signal jointly determine which row of pixels is the current row. At the same time, at the rising edge of the "Read" signal, the photosensitive unit of the current pixel area is sampled and sent to a buffer row. This buffer row is output to the output row "Vout" through multiplexing technology. The multiplexer is controlled by the decoded output of the Y signal. The most recent output of the Y decoding is used to read
out the dynamic dark reference. Therefore, in the normal image readout mode, the most important Y decoding output is O×15F.
ME1010 saves the photosensitive signal of the photosensitive area (current area) corresponding to the XY address specified by the external logic circuit (microcontroller or ASIC) to the analog signal frame buffer. The original pixel signal output by the "Vout" pin is a negative polarity signal. In other words, the level of the black signal is higher than the level of the white signal.
Black reference cell row:
The first row (bottom) of the photosensitive array is used to sense the dynamic black (reference background). This dynamic black reference is generated by the photosensors in the first row before the sampling process begins. When this row is selected, that is, the Y decoding output is 15F (351), the reference signal is output to the "Vref" pin as a subsequent source. This provides a black reference for shutting down the signal processor and the on-chip analog-to-digital converter.
On-chip 8-bit analog-to-digital converter (8-bADC);
The on-chip 8-bit analog-to-digital converter can convert analog image signals into digital image signals. The functional timing diagram of the fast ADC is shown in Figure 1 below. The analog image signal is sampled at the falling edge of the "ADCclock" signal, the A/D conversion is completed during the low level period of the "ADC Clock", and the digital signal is output at the rising edge of the "ADCClock". This causes a conversion delay of half a clock cycle (low level width). The conversion range is determined by the external reference voltage. The compensation signal input in the form of power can reduce the deviation signal to zero.



2 Hardware system
The hardware of this system mainly consists of sensors and peripheral circuits, key circuits, reference voltage circuits, MCU processors, display circuits, communication interface circuits with the host computer, power supply circuits, etc., as shown in Figure 2.


The sensor uses the ME1010 CMOS image sensor, and its peripheral circuits mainly consist of address decoding and driving circuits, data buses, sampling clocks and control circuits, A/D control circuits, etc.

The key circuit is relatively simple, mainly including the flower counting, length counting, and pause keys, etc., to realize the functions of flower counting, length counting, and pause maintenance.
The reference voltage circuit provides the A/D conversion reference level for the image sensor. The specific circuit is shown in Figure 3.


The display circuit completes the display of the flower counting and length counting results, and is mainly composed of a display module and a drive circuit. The display module is implemented by a digital tube, and a liquid crystal display module can also be used. The former has a simple structure and low cost.
The communication interface circuit realizes the data transmission between each flower counter terminal and the host computer. During the system development stage, the sensor data can also be obtained through the communication interface circuit to set a reasonable setting value.
The MCU can be an 8-bit single-chip microcomputer.

3 Software system
The software system is mainly composed of the main program, key scanning program, display program, etc.
The main program is mainly responsible for processing the sensor signal and calling the key subroutine and display subroutine. Figure 4 Software flow chart



4 Simulation
The program is written in assembly language, and each program is simulated on the single-chip microcomputer IDE platform UV2. The simulation results show that the functions of each program module are correct. The hardware simulation is carried out using analog signals, and the simulation results show that the system is fully capable of realizing the predetermined functions: according to the knot setting parameters, the input signal is processed and the number of knots on the current spindle is counted.