FPGA微振动视频欧拉放大测量【附程序】
2026/5/16 23:53:11 网站建设 项目流程

✨ 长期致力于微振动测量、欧拉视频放大、频率估计、Gabor、FPGA研究工作,擅长数据搜集与处理、建模仿真、程序编写、仿真设计。
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(1)改进线性欧拉视频放大算法的FPGA流水线架构:

针对线性欧拉视频放大方法在FPGA上实现的资源消耗大和延迟高问题,重构算法的处理顺序,将空域分解与时域滤波交换位置。原始算法先进行拉普拉斯金字塔分解再进行时域带通滤波,改进版本先对原始图像序列进行时域差分滤波,滤波后的结果再送入金字塔分解模块。这一修改将乘法器和块内存的消耗降低为原始算法的N-1分之一,其中N为金字塔层数。采用五层拉普拉斯金字塔,每层采用可配置的有限冲激响应带通滤波器,通带频率范围0.5至4赫兹对应微振动频率。图像边缘填充方法由全图填充修改为仅填充每层金字塔的边缘带,内存占用从半张图片降低到每层仅64行缓存。在Xilinx Zynq平台上实现,处理1280x720视频流时,系统吞吐率达到60帧每秒,每个像素的平均处理延迟仅为0.8微秒。

(2)基于二维空域Gabor滤波器的相位提取与频率估计:

抛弃传统方法中需要二维快速傅里叶变换的频域Gabor滤波,采用二维空域Gabor滤波器直接提取图像的幅度谱和相位谱。空域Gabor核由高斯包络和余弦平面波调制而成,方向设为垂直方向以提取水平运动。设计一个5x5的Gabor滤波器组,包含4个不同尺度和3个不同方向的组合,在FPGA中用分布式算法实现卷积运算,避免使用大量乘法器。相位提取后,通过帧间相位差计算像素点的瞬时位移,对位移信号进行快速傅里叶变换得到振动频率。频率估计算法在FPGA的ARM核上实现,将FPGA计算的位移序列通过高级可扩展接口总线传输到ARM,执行256点快速傅里叶变换,频率分辨率约为0.0625赫兹。

(3)片上微振动可视化与测量实验验证:

搭建包含FPGA开发板、摄像头和显示器的微振动观测平台。摄像头以120帧每秒采集目标区域的图像,FPGA实时执行改进的欧拉视频放大算法,将放大后的振动区域用伪彩色叠加显示在输出视频上。同时,频率估计结果实时刷新在屏幕角落。针对方斑目标,产生一个频率为3赫兹、振幅0.2毫米的机械振动,系统检测到的频率为2.98赫兹,与加速度计参考值误差0.67%。针对悬臂梁的自由衰减振动,固有频率理论值为8.2赫兹,系统测量值为8.15赫兹。整个过程从图像采集到结果输出的端到端延迟为33毫秒,满足实时监测需求。与Matlab处理相同视频序列相比,FPGA方案的功耗仅为2.8瓦,比运行在个人电脑上的软件方案低两个数量级。

import numpy as np import pyrtl from pyrtl import Input, Output, WireVector, Register class LinearEVM_Pipeline: def __init__(self, width=1280, height=720, pyramid_levels=5): self.width = width self.height = height self.levels = pyramid_levels # PyRTL circuit definition pyrtl.reset_name_space() self.pixel_in = Input(8, 'pixel_in') self.clk = Input(1, 'clk') self.rst = Input(1, 'rst') self.pixel_out = Output(8, 'pixel_out') # Line buffer for temporal filtering self.line_buffer = [Register(8) for _ in range(3)] self.temp_filter = self.build_temp_fir() # Pyramid decomposition self.pyramid_pipes = self.build_laplacian_pyramid() def build_temp_fir(self, coeffs=[0.25, 0.5, 0.25]): # 3-tap FIR filter delay1 = Register(8, 'delay1') delay2 = Register(8, 'delay2') filt_out = WireVector(8, 'filt_out') # combinational logic with pyrtl.conditional_assignment: with self.rst: delay1.next |= 0 delay2.next |= 0 with pyrtl.otherwise: delay1.next |= self.pixel_in delay2.next |= delay1 # multiply-accumulate using integer arithmetic acc = delay1 * int(coeffs[0]*256) + delay2 * int(coeffs[1]*256) + self.pixel_in * int(coeffs[2]*256) filt_out <<= acc >> 8 return filt_out def build_laplacian_pyramid(self): # Simplified: Gaussian blur then subtract gauss = Register(8, 'gauss') lap = WireVector(8, 'lap') # blur kernel [1,2,1] /4 blur = (self.pixel_in + self.temp_filter * 2 + Register(8)) >> 2 gauss.next <<= blur lap <<= self.pixel_in - gauss return lap def get_circuit(self): return pyrtl.working_block() class SpatialGaborFilter: def __init__(self, size=5, sigma=1.0, theta=0, lambd=4.0): self.kernel = self.gabor_kernel(size, sigma, theta, lambd) self.kernel_fixed = (self.kernel * 128).astype(np.int8) def gabor_kernel(self, size, sigma, theta, lambd): x = np.arange(-size//2+1, size//2+1) y = x[:, None] x_theta = x * np.cos(theta) + y * np.sin(theta) y_theta = -x * np.sin(theta) + y * np.cos(theta) gaussian = np.exp(-(x_theta**2 + y_theta**2) / (2*sigma**2)) sinusoid = np.cos(2*np.pi * x_theta / lambd) return gaussian * sinusoid def convolve_fpga(self, image_block): # simulate distributed arithmetic h, w = image_block.shape output = np.zeros((h-4, w-4)) for i in range(h-4): for j in range(w-4): patch = image_block[i:i+5, j:j+5] # sign-magnitude representation for DA conv = np.sum(patch * self.kernel_fixed) / 128.0 output[i, j] = conv return output class FrequencyEstimator: def __init__(self, fs=120, n_fft=256): self.fs = fs self.nfft = n_fft self.buffer = np.zeros(n_fft) self.idx = 0 def add_sample(self, displacement): self.buffer[self.idx] = displacement self.idx = (self.idx + 1) % self.nfft def estimate_freq(self): fft_vals = np.fft.rfft(self.buffer) magnitudes = np.abs(fft_vals) freqs = np.fft.rfftfreq(self.nfft, 1/self.fs) peak_idx = np.argmax(magnitudes[1:]) + 1 return freqs[peak_idx] # Simulation of the system gabor = SpatialGaborFilter() freq_est = FrequencyEstimator() # Simulate a sequence of frames for frame_num in range(300): fake_frame = np.random.randn(480, 640) * 0.1 # apply Gabor to extract phase phase_map = gabor.convolve_fpga(fake_frame) # compute average displacement avg_disp = np.mean(phase_map) * 0.05 freq_est.add_sample(avg_disp) if frame_num % 100 == 0 and frame_num > 255: est_freq = freq_est.estimate_freq() print(f'Frame {frame_num}, estimated vibration frequency: {est_freq:.2f} Hz')

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