Tham khảo tài liệu 'advances in analog circuits part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Analog Circuit for Motion Detection Applied to Target Tracking System 319 Target .ựE Ý P Photoreceptor L Large monopolar cell D Delay neuron C Correlator a b Fig. 1. Unit model for motion detection. a Model. b Transient response of each cell. and VD and ID are decreased by MN2. The current IC is 0 since the nMOS transistor MN4 turns off when the target is not projected on PD2. The target moves toward the right side and the target projected on PD2. Then the voltage VL2 becomes about VDD and IC is equal to ID since MN4 turns on. IC is converted to the output voltage VE by the integration circuit constructed with the capacitor CO and the nMOS transistor MN5 where the voltage VG2 is set to the constant value. VE is proportional to the velocity of the target. In the case that the circuit is applied to the target tracking system the voltage Vcenter described in section 4 is generated by the PD located on the center of the array. When the target locates on the center of the input part VE shows about 0 by the nMOS transistor MN6. 320 Advances in Analog Circuits Photoreceptor P1 and Large monopolar cell L1 i Photoreceptor P2 1 and L2 Correlator C DD PD center Id mn3 MN6 Delay neuron D Fig. 2. Unit analog motion detection circuit. 4. Target tracking model based on the biological vision system Figure 3 shows the model for tracking the target based on the biological vision system. The unit model EMD in Fig. 1 are arrayed in one-dimensionally. By using this model it is able to track the target and capture the target in the center of the input parts. In this section I will describe the details of the model. The input part of the model is the photoreceptor P array. P generates the signal which is proportional to light intensity. The signal of P is input to each EMD. EMDR generates the signal VER when the target moves toward the right side. EMDL generates the signal VEL when the target moves toward the left side. I describe about the model in Fig. 3 in the case that the target .
