OpenCV provides four different edge detection operators, or High-pass filters: Sobel,scharr and Laplacian operators and canny operators, the specific detection steps are as follows: image filtering : The algorithm of edge detection is based on first and second derivative of image gray value, but the derivative is usual
Note: This article is translated from: pedestrian detection OpenCV.
Do you know the built-in pedestrian detection method inside the OpenCV? In OpenCV, there is a hog+ linear SVM model that can detect pedestrians in images and videos. If you are not familiar with the directio
than the minimum confidence
If confidence > args["confidence"]: # Extract the index of the class label from the ' detections ', # then compute the (x, y)-coordinates of the bounding box for # the object idx = Int (det Ections[0, 0, I, 1]) box = detections[0, 0, I, 3:7] * Np.array ([w, H, W, H]) (StartX, Starty, EndX , EndY) = Box.astype ("int") # Display the prediction label = ' {}: {:. 2f}% '. Format (Classes[idx], C Onfidence *) Print ("[INFO] {}". Format (label)) Cv2.
resources on the Internet to help you understand this great edge detection algorithm. Threshold selection, to try to choose the low threshold!!! Because if the threshold selection is too high, it causes the outer quadrilateral of the invoice to be unclosed, which prevents the contour line from being found correctly. Although the low threshold value produces a lot of noise, the noise will be ignored in subsequent steps because contour
Traditional edge detection:
OpenCV inside of the two functions, Cv2. Canny () and cv2.findcontours ():
It looks like it's easy to come true, but the real picture is that it doesn't work in a complex background.
The detection effect of the canny algorithm relies on several threshold parameters, and the selection of these threshold parameters is usually a human-s
The interaction between humans and robots constantly evolve and adopt different tools and software to increase the comfort of humans.
In this article, I explore nine tutorials which show you different methods to detect and recognize hand.
The OpenCV library is not enough to start your project. This library provides for you the software side, but for you also need hardware. In the hardware category enters a developed platform able to run the
Note that the axis of the OPENCV, the x-axis to the right, and the width corresponding to the Y axis downward, and the height of the corresponding;
1. MOG2 and KNN
Mog:mixture of Gaussian
Import cv2
cap = Cv2. Videocapture ('./data/video/768x576.avi ')
knn_sub = CV2.CREATEBACKGROUNDSUBTRACTORKNN ()
mog2_sub = CV2.CREATEBACKGROUNDSUBTRACTORMOG2 ()
while True:
ret, frame = Cap.read ()
if not ret:
break
Mog_ Sub_mask = mog2_sub.app
Reference: Pedestrian detection using hog features and SVM Classifier:Http://blog.csdn.net/carson2005/article/details/7841443
Hog + SVM has excellent Pedestrian detection effects due to its characteristics, but it also has good effects on other targets. Here we will expand the scope.
Carson2005's blog article describes how to use opencv to implement sample trai
Cvcanny function of Image edge detection--OPENCV Category: C/ void Cvcanny (const cvarr* image, cvarr* edges, double threshold1, double threshold2, int aperture_size=3); Image single-channel input images. Edges the output image of a single-channel storage edge threshold1 The first threshold threshold2 the second threshold Aperture_sizesobel operator kernel size (see Cvsobel). The function Cvcanny uses the C
small, ignore it PrintCv2.contourarea (c)ifCv2.contourarea (c) "Min_area"]: Continue #compute the bounding box for the contour, draw it on the frame, #and update the text #calculates the bounding box of the outline, drawing the box in the current frame(x, Y, W, h) =Cv2.boundingrect (c) Cv2.rectangle (frame, (x, y), (x+ W, y + h), (0, 255, 0), 2) Text="occupied" #Draw the text and timestamp on the frame #wr
Document directory
1) load the cascade classifier
2) read Video Streams
3) use this classifier for each frame
4) display the target
The target detection method supported by opencv is the classifier training based on the Haar feature of the sample to obtain the cascade boosted classification ). Note: In addition to haar features, the new C ++ interface can also use the HSV features.
First, we will in
motion #counterlastuploaded =timestamp Motioncounter=0#Otherwise, the hostel is not occupied Else: Motioncounter=0#Check to see if the frames should is displayed to screen ifconf["Show_video"]: #Display the security feedCv2.imshow ("Security Feed", frame) key= Cv2.waitkey (1) 0xFF#if the ' Q ' key is pressed, break from the Lop ifKey = = Ord ("Q"): Break #clear the stream in preparation for the next frameRawcapture.truncate (0)Conf.json{ "Sh
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1.1 cvkan
1.2 cvCreateTrackbar
1.3 CvTrackbarCallback
[OpenCV Getting Started Guide] Part 3 "Canny edge detection"
The principle of image edge detection is to detect all the gray-scale points in the image, and these points are connected to form several lines, which can be called the edge of the image.
A multi-level edge
Original address: opencv for iOS Study Notes (5)-mark Detection 2
Relevance search
Void markerdetector: const extends svector contours, STD: vector
We have obtained a series of suspicious tags in the above method. To further confirm whether they are the tags we want, we also need the following three steps:
1. Remove the Perspective Projection to get the rectangle
Tags: des style blog HTTP color OS ar use
Feature Points, also known as points of interest and key points, are highlighted and representative points in the image. Through these points, we can identify images, perform image registration, and perform 3D reconstruction. This article mainly introduces several functions in opencv to locate and represent key points. I. Harris corner
A corner is the most basic key point in an image. It is composed of s
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