opticalflow

问题 We're actually working on an image analysis project where we need to identify the objects disappeared/appeared in a scene. Here are 2 images, one captured before an action has been made by the surgeon and the other afterwards. BEFORE: AFTER: First, we just calculated the difference between the 2 images and here is the result (Note that I added 128 to the result Mat just to have a nicer image): (AFTER - BEFORE) + 128 The goal is to detect that the cup (red arrow) has disappeared from the scene

问题 I'm using the OpenCV wrapper - Emgu CV, and I'm trying to implement a motion tracker using Optical Flow, but I can't figure out a way to combine the horizontal and vertical information retrieved from the OF algorithm: flowx = new Image<Gray, float>(size); flowy = new Image<Gray, float>(size); OpticalFlow.LK(currImg, prevImg, new Size(15, 15), flowx, flowy); My problem is not knowing how to combine the info of vertical and horizontal movement in order to build the tracker of moving objects? A

问题 I am trying to visualize the output of calcOpticalFlowPyrLK() (OpenCv v3.0.0). I am not trying to draw whole image with optical flow, only the direction arrow. The problem is, I can't get to the output as in the examples. Every 10 frames I renew the points for the calculation of the flow. The function itself calcOpticalFlowPyrLK(CentroidFrOld, CentroidFrNow, mc, CornersCentroidNow, feat_found, feat_errors, Size(15, 15), 2, cvTermCriteria(CV_TERMCRIT_ITER | CV_TERMCRIT_EPS, 10, 0.03), 0);

问题 I want to calculate optical flow using cvcalcopticalflowBM function in opencv 2.4.7 When I complied the belowed code. The error message is "Sizes of input arguments do not macth() in cvcalcopticalflowbm I do not understand why it is. Please help me. Thank you advance. #define BS 5 IplImage *imgA = NULL, *imgB = NULL; IplImage *grayA = NULL, *grayB = NULL; IplImage *velx = NULL, *vely = NULL; IplImage *result = NULL; imgA = cvLoadImage("00.jpg", 1); imgB = cvLoadImage("01.jpg", 1); grayA =

问题 I am working on the following code: filename = 'C:\li_walk.avi'; hVidReader = vision.VideoFileReader(filename, 'ImageColorSpace', 'RGB','VideoOutputDataType', 'single'); hOpticalFlow = vision.OpticalFlow('OutputValue', 'Horizontal and vertical components in complex form', 'ReferenceFrameDelay', 3); hMean1 = vision.Mean; hMean2 = vision.Mean('RunningMean', true); hMedianFilt = vision.MedianFilter; hclose = vision.MorphologicalClose('Neighborhood', strel('line',5,45)); hblob = vision

问题 I have used cv::calcOpticalFlowFarneback to calculate the optical flow in the current and previous frames of video with ofxOpenCv in openFrameworks. I then draw the video with the optical flow field on top and then draw vectors showing the flow of motion in areas that are above a certain threshold. What I want to do now is create a bounding box of those areas of motion and get the centroid and store that x , y position in a variable for tracking. This is how I'm drawing my flow field if that

问题 I am using the Lucas Kanade Optical Flow algorithm from openCV library in C#; There are series of frames that in every two of them I want to find out what was the optical flow and show it in a pictureBox. I could fetch the velX & velY from following function: Emgu.CV.OpticalFlow.LK(imGrayCurrent, imGrayNext, windSize, velX, velY); Now,How should I use these two for show the flow between two frames? or in other words how should I get the displacement of pixels? Tnx 回答1: A common way is to use

问题 I have a question concerning two parameters in CalcOpticalFlowPyrLK() class.Here is the link of the documentation: http://docs.opencv.org/trunk/modules/video/doc/motion_analysis_and_object_tracking.html?highlight=calcopticalflowpyrlk#cv2.calcOpticalFlowPyrLK The first parameter is the " err ". In the documentation this is defined as the tracking error of it's feature, but they don't give any details. Error in respect of what? Secondly the parameter "status".They define it as the state if a

问题 I'm working on a project where I need to implement collision avoidance using OpenCV. This is to be done on iOS (iOS 5 and above will do). Project Objective: The idea is to mount an iPad on the car's dashboard and launch the application. The application should grab frames from the camera and process these to detect if the car is going to collide with any obstacle. I'm a novice to any sort of image processing, hence I'm getting stuck at conceptual levels in this project. What I've done so far:

问题 I am trying to use the output of Opencv's dense optical flow function to draw a quiver plot of the motion vectors but have not been able to find what the function actually outputs. Here is the code: import cv2 import numpy as np cap = cv2.VideoCapture('GOPR1745.avi') ret, frame1 = cap.read() prvs = cv2.cvtColor(frame1,cv2.COLOR_BGR2GRAY) hsv = np.zeros_like(frame1) hsv[...,1] = 255 count=0 while(1): ret, frame2 = cap.read() next = cv2.cvtColor(frame2,cv2.COLOR_BGR2GRAY) flow = cv2