Li Hongqin

Real-Time Digital Image Exposure Status Detection and Circuit Implementation

Auto exposure is an important part of digital image signal processing. We studied the detection of the exposure status in this paper, and fast and parallel detection method was presented. The method comprises the following steps: first obtaining the current image, counting the numbers of pixels in bright and dark regions of the image and obtaining these pixels brightness; then determining exposure parameters based on the proportions of the counted numbers of pixels in bright and dark regions with preset value respectively; if the actual proportion is lower than preset value, then continue to adjust exposure parameters until pixel brightness value reaches preset brightness threshold. Experiments show that the computational complexity and operation demand is low, which can quickly determine the exposure status of the image, improving the real-time capability in image exposure control. The proposed method will make the whole digital image signal processing system works smoothly and be reliable. The circuit implementation of this method is simple with high real-time controllability. This method has been applied for China patent successfully.

Digital decimation filter design and simulation for delta-sigma ADC with high performance

This paper study a kind of design method about the digital decimation filter design for delta-Sigma ADC with high performance and validated it by simulation using MATLAB tool. A 16-bit digital decimation filter design for stereo audio delta-sigma ADC has been developed. A two-stage decimation filter architecture which can reduce digital switching noise was also introduced in this design. A merged four-stage comb filter is used for the first stage, and a bit-serial finite-impulse-response (FIR) filter is used for the second stage. In addition, a high pass filter is used to compensate filters DC offset. The design simulated using MATLAB according to this scheme can achieve higher performances.

Vehicle Traffic Flow Detection System Based on Video Images under Haze Environment

In order to study vehicle traffic flow under extreme weather conditions such as haze and so on, this paper mainly focus on the application of related video processing technology in vehicle detection, and studies the traffic flow detection method based on video images. Based on the Gaussian mixture model, background detection and video de-haze algorithm is used to model the background, video frame is extracted and HSV model is used to make the video image clearer and then traffic flow is detected. MATLAB simulation results show that the proposed flow detection system can produce high detection accuracy of the vehicle in the haze environment.

Smart Cars Path Identification based on Optical Sensors

This paper describes the design of intelligent car control system hardware and software, the entire system is involved in car models mechanical structure adjustment, the sensor circuit design and signal processing, control algorithms and strategies to optimize other aspects. A 16-bit free scale microcontroller MC9SXS128 was selected as the controller; information of road condition and car speed collected by the integrated laser tubes could be obtained by the single chip. Digital PID and PWM control techniques are used to real-time control the servo steering and front wheel steering angle, so as to guarantee a fast and safe driving of smart car along the given path.

Nonlinear System Identification based on Orthonormal Wavelet

Owing to the switching nature of power electronic systems, the dynamic behaviors of these systems are generally nonlinear. It’s a good approach to modeling dynamic nonlinear systems using nonlinear system identification. Compactly supported orthogonal wavelets have certain properties useful for system identification. This paper proposed an identification scheme for dynamic nonlinear system model using Haar wavelet. Simulation result for PWM boost DC-DC converter shows the validation of this scheme.

Image Registration Algorithm Based on Image Normalization

Image registration is a central problem to many tasks for image processing and is widely used in many applications such as automatic navigation, medical diagnostics, computer vision and etc. An image registration scheme using image normalization is proposed in this paper. Image feature points robust to rotation, scaling, noise and JPEG compression are obtained by the affine invariant Harris feature point detector and used to make the Delaunay triangle to estimate the affine transform parameters through image normalization. Simulation results show that the proposed scheme can effectively estimate rotation, scaling and translate parameters and has high estimation accuracy under common image attacks.

Modeling and Simulation of Anti-lock Braking System based on Fuzzy Control

Car security system can be divided into two main parts: one is the active security systems; the other is the passive security system. Anti-lock braking system (ABS) is an important active security systems. It can effectively enhance the driving stability, reduce the braking distance, and to some extent, prevent the accident from happening. The emergency brake of a moving car may cause sudden locking of the wheel. The front wheel locking will cause loss of vehicle steering force; the rear wheels locking will make the vehicle slide sideways and tail flick. These problems are often one of the factors causing the accident. If a vehicle equipped with ABS, the tires will not be in a locking state when there is an emergency braking, which enhances security. This article use of Matlab / Simulink software to implement simulation of anti-lock braking system, as well as modeling and control of the ABS. After the study of several car anti-lock braking system control method, the option of using the fuzzy control door limit control strategy can make the simulation results more accurate.

Fragile Watermark-based Electronic Police Information Processing System

A fragile watermarking algorithm applying to electronic police information processing system is proposed in this paper. First license plate is extracted as the embedded watermark from illegal driving automobile image and then was embedded in DCT domain; watermark was extracted without original image. MATLAB simulation results show that the proposed watermarking algorithm can be embedded in the illegal driving automobile image captured by electronic eye, and watermark can be exactly extracted under the conventional image processing such as noise addition & JPEG compression. When watermarked image is subjected to cropping and license plate content tampering attack, the extracted watermark is not clear enough, thus indicates the illegal driving automobile image was tampered.

A RSC Invariant Watermarking Scheme Utilizing Image Normalization for Synchronization

A rotation, scaling and cropping invariant watermarking scheme using image normalization is proposed in this paper. Watermark is adaptively embedded in discrete wavelet transform. Robust image feature points against rotation, scaling, noise and JPEG compression are obtained by the affine invariant Harris feature point detector and used to make the Delaunay triangle to estimate the affine transform parameters applied on the watermarked image through image normalization. Watermark extraction is carried out after watermarked image has been synchronized. Experimental results show that the proposed scheme can effectively resist rotation, scaling and cropping attacks as well as common signal processing.

18 bit Delta-Sigma DAC in 0.18um CMOS process

The Delta-Sigma Digital-to-Analog Converter ( Δ - Σ) is designed in Verilog HDL for stereo video system. This DAC supports 16-bit or 18-bit input data and includes an 8x digital interpolation filter followed by a 64x oversampled delta-sigma modulator. The modulator output controls the reference voltage input to analog low-pass filter. The architecture allows for adjustment of sample rate by changing the master clock frequency. This DAC is implemented in 0.18um CMOS process with the advantages of lower power consumption and higher performances demonstrated by chip test. It has been successfully used in practice.