中国科学技术大学:光流性能(PPT讲稿)Performance of Optical Flow

Performance of optical flow Barron, fleet and beauchemin JcV12:1,1994 http://www.csd.uwoca/faculty/barron/
Performance of Optical Flow Barron, Fleet and Beauchemin IJCV 12:1, 1994 http://www.csd.uwo.ca/faculty/barron/

Performance of optical flow Evaluation of different optical flow techniques Accuracy reliability density of measurements a common set of synthetic and real sequences Several optical flow methods Differential Matching Energy-based Phase-based
Performance of Optical Flow • Evaluation of different optical flow techniques – Accuracy, reliability, density of measurements • A common set of synthetic and real sequences • Several optical flow methods – Differential – Matching – Energy-based – Phase-based

Performance of optical flow Accurate and dense velocity measurement Accurate 2d motion filed estimation is ill posed Inherent differences between the 2d motion field and intensity variations Only qualitative information can be extracted
Performance of Optical Flow • Accurate and dense velocity measurement • Accurate 2d motion filed estimation is illposed – Inherent differences between the 2D motion field and intensity variations • Only qualitative information can be extracted

Optical flow Process · Three stages Perfiltering or smoothing with low-pass /band-pass filters in order to extract signal structure of interest enhance the signal-to-noise ratio Extraction of basic measurements Spatiotemporal derivatives Local correlation surface Integration of measurements to produce 2D flow field Often involves assumptions about the smoothness of the underlying flow field
Optical Flow Process • Three stages – Perfiltering or smoothing with low-pass/band-pass filters in order to • extract signal structure of interest • enhance the signal-to-noise ratio – Extraction of basic measurements • Spatiotemporal derivatives • Local correlation surface – Integration of measurements to produce 2D flow field • Often involves assumptions about the smoothness of the underlying flow field

Differential Techniques First-order derivatives and based on image translation /(x,t)=l(X-v1,0 Intensity Is conserved d(r, t) 0 t VI(x,1)v+1(x,)=0V/(x,)=(1(x,),(x1) Normal velocity s(x,) 1, (x, t) V(x, t) n=sn n(x VI(x, t)I
Differential Techniques • First-order derivatives and based on image translation • Intensity is conserved • Normal velocity I t I t ( , ) ( ,0) x x v = − ( , )T v = u v ( , ) 0 dI t dt = x ( , ) ( , ) 0 t + = I t I t x v x ( , ) ( ( , ), ( , ))T x y = I t I t I t x x x n v n = s ( , ) ( , ) ( , ) t I t s t I t − = x x x ( , ) ( , ) ( , ) t t I t = x n x x

Differential Techniques Second-order differential In (x, t)I(x, On./Iu(x, l(x,)n(x,) xt 0 Stronger restriction than first-order derivatives on permissible motion field VI(x.,1)v+l1(x,)=0 Can be combined with 1st order in isolation or together(over determined system) Velocity estimation from 2nd-order methods are often assumed be to sparser and less accurate than estimation from 1st-order methods
Differential Techniques • Second-order differential • Stronger restriction than first-order derivatives on permissible motion field • Can be combined with 1st order in isolation or together (overdetermined system) • Velocity estimation from 2nd -order methods are often assumed be to sparser and less accurate than estimation from 1st -order methods 1 2 ( , ) ( , ) ( , ) 0 ( , ) ( , ) ( , ) 0 xx yx tx xy yy tx I t I t v I t I t I t v I t + = x x x x x x ( , ) ( , ) 0 t + = I t I t x v x

Differential Techniques Additional constraints Fits the measurements in each neighborhood to a local model for 2d velocity Using least squares minimization or Hough transform Global smoothness
Differential Techniques • Additional constraints – Fits the measurements in each neighborhood to a local model for 2d velocity • Using least squares minimization or Hough transform – Global smoothness

Differential Techniques I(x, t)must be differentiable Temporal smoothing at the sensors is needed to avoid aliasing Numerical differentiation must be done carefully If aliasing can not be avoided in image acquisition apply differential techniques in a coarse-to-fine manner
Differential Techniques • must be differentiable – Temporal smoothing at the sensors is needed to avoid aliasing – Numerical differentiation must be done carefully • If aliasing can not be avoided in image acquisition – Apply differential techniques in a coarse-to-fine manner I t ( , ) x

Horn and schunck Combine gradient constraint with a global smoothness term, minimizing 「(Vv+4)2+(+)k n=0.5 instead of 2=100 Ⅰ(Ⅰv+Ⅰ uk+=ukx v=10=0 a2+2+ k+1 k(1n+1v+1) a2+2+Ⅰ
Horn and Schunck • Combine gradient constraint with a global smoothness term, minimizing ( ) ( ) 2 2 2 2 D t 2 2 + + + I I u v d v x 0 0 v u = = 0 1 222 1 222 ( ) ( ) k k k k x x y t x y k k k k y x y t x y I I u I v I u u I I I I u I v I v v I I + + + + = − + + + + = − + + = = 0.5 instead of 100

Horn and schunck Relatively crude form of numerical differentiation can be source of error Spatiotemporal smoothing Gaussian prefilter with o= 1.5 pixels in space and 1. 5 frames in time 4-point central differences for differentiation mask;(-1,8.0,-81)
Horn and Schunck • Relatively crude form of numerical differentiation can be source of error • Spatiotemporal smoothing – Gaussian prefilter with 1.5 pixels in space and 1.5 frames in time • 4-point central differences for differentiation – mask 1 ( 1,8,0, 8,1) 12 − − =
按次数下载不扣除下载券;
注册用户24小时内重复下载只扣除一次;
顺序:VIP每日次数-->可用次数-->下载券;
- 《大学物理》课程教学资源(PPT讲稿)第六章 热力学基础(热力学第一定律).ppt
- 西安电子科技大学物理与光电工程学院:电波传播基本概念(PPT课件).pptx
- 清华大学:粒子物理与核物理实验中的数据分析(PPT讲稿)基本概念.pptx
- 西安电子科技大学:《电波传播概论》课程教学资源(PPT课件讲稿)第一部分 电磁波理论基础 Fundamental of Electromagnetic Waves Propagation(主讲:李仁先).pptx
- 中科院高能物理研究所:四通道低噪声GEM探测器前端读出ASIC设计(吕继方).ppt
- 《量子力学》课程PPT教学课件:第五章 近似方法.ppt
- 《电磁场与电磁波》课程教学资源(PPT课件讲稿)第5章 均匀平面波在无界媒质中的传播.ppt
- 中国科学院理论物理所:Collider Phenomenology of SUSY Cosmic Connections(杨金民).ppt
- GRB的突发伽玛射线暴来自共振逆康普顿散射机制.ppt
- 原子的基本状况(PPT讲稿)α粒子散射理论.ppt
- 中国科技大学化学物理系:介观化学体系(PPT讲稿)非平衡非线性反应动力学.ppt
- 中国科学技术大学:生物大分子波谱学原理(全相关谱TOCSY、同核核磁实验方法).ppt
- 北京大学:格点上的赌博(PPT讲稿)格点场论介绍.ppt
- 《大学物理》课程PPT教学课件:周期性运动 periodic motion.ppt
- 湖北汽车工业学院:真空中静电场的高斯定理及其应用(PPT讲稿).ppt
- 电子科技大学:干涉(PPT讲稿)Interference.ppt
- 《大学物理》课程PPT教学课件:第七章 电流与磁场.ppt
- 《电子储存环物理》课程PPT教学课件:第六讲 束流寿命.pptx
- 大连民族学院物理与材料学院学院:显微镜的组装 Assemblage of microscope.ppt
- 中国科学技术大学物理系:《半导体器件原理》课程教学资源(PPT课件)第三章 双极型晶体管.ppt
- 赣南师范大学(赣南师范学院):《光电子技术学》课程教学资源(PPT课件)光束的调制和扫描(光束扫描技术).ppt
- 《大学物理》课程教学资源(PPT课件讲稿)第22章 量子力学基础 fundament of quantun mechanics.ppt
- 清华大学:Split Two-Higgs Doublet and Neutrino Condensation.ppt
- 安徽理工大学:《大学物理》课程教学资源(PPT课件)第十八章 量子物理基础 第三讲 量子力学应用初步.ppt
- 四川大学物理学院:Optimizing pointer states for dynamical evolution of quantum correlations under decoherence.ppt
- Non-photonic electron yields in p+p collisions at 200 GeV with reduced detector material in STAR.ppt
- 精密位移量的激光干涉测量方法及实验.ppt
- 电磁波(PPT讲稿)Electromagnetic wave.ppt
- 华东师范大学:低耦合阈值导致可激发系统的自维持振荡(王健雄).ppt
- 南开大学:《大学物理学基础》课程教学资源(PPT课件讲稿)第六章 机械振动和机械波(简谐振动).ppt
- 中国科学技术大学:《X射线光电子能谱学 X-Ray Photoelectron Spectroscopy》课程教学课件(原理、方法和应用)第1章 XPS的物理基础(主讲:麻茂生).pps
- 中国科学院:高能物理研究所的粒子物理研究 Particle Physics Research in Institute of High Energy Physics.ppt
- 清华大学:SUSY Higgs at the LHC plus a bit more.ppt
- 山东大学:Testing Realistic Seesaw Model at LHC(PPT讲稿,主讲人:郑亚娟).ppt
- 理论力学(PPT课件讲稿)哈密顿力学.ppt
- 《电磁学》课程教学资源(PPT课件讲稿)第六章 静电场.ppt
- 《电动力学》课程教学资源:第三、四章 复习.ppt
- 《电磁学》课程教学资源(PPT讲稿)电磁感应习题解答.ppt
- 《大学物理》课程教学资源(PPT讲稿)复习资料(共九部分).ppt
- 《电磁场与电磁波》课程教学资源(PPT课件讲稿)第六章 平面电磁波.ppt