Introduction to the idea of cross-validation (Crossvalidation) methodThe following is referred to as cross-validation (crosses Validation) for CV.CV is used to verify the performance of the classifier a statistical analysis method, the basic idea is to put the original data (dataset) in a sense of grouping, part of the training set (train set), the other part as a validation set (validation set), first training the classifier with the training set, using the validation set to test the trained mo
the argument is NanText Display functionSize cv::gettextsize (const String text,intFontface,DoubleFontscale,intThicknessint*baseLine);//calculates the width and height of a text string.//baseline:y-coordinate of the baseLine relative to the Bottom-most text point.void CV::p uttext (inputoutputarray img, const Stringtext, point org,intFontface,DoubleFontscale, Scalar color,intthickness=1,intLinetype=line_8
TESSERACTOCR to recognize text [self tesseractrecognizeimage:numberimage compleate:^ (nsstring *numbaertext) {compleate ( Numbaertext); }];}Scan ID image and preprocess, locate the number area picture and return-(UIImage *) Opencvscancard: (UIImage *) Image {Convert UIImage to Mat Cv::mat resultimage; Uiimagetomat (image, Resultimage);Converted to grayscale Cvtcolor (Resultimage, Resultimage, Cv::color_bgr
When trying to perform feature matching between different images, it is often the case that the size and direction of the image change, in short, the problem of scale change. Each image is taken at a different distance from the target object, so the object to be identified will naturally have different dimensions in the image.Therefore, the introduction of scale invariant features in computer vision, the main idea is that each detected feature points are accompanied by the corresponding scale fa
Cool liukun321
From: http://blog.csdn.net/liukun321
Essentially, an image is a matrix composed of numbers. Opencv 2.x represents an image by the data structure of CV: mat. Each element of the matrix represents a pixel. For color images, the element of the matrix is a ternary number. With this new understanding of the image, we can try to use opencv to process the image.Let's take a look at the image to be processed today:
Today's topic is to acce
Original address: opencv for iOS Study Notes (5)-mark Detection 2
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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 on the plane/front.
2. Use the Otsu algorithm to calculate the threshold value of an image.
3. Finally, the mark recognition code
Create a new C + + library projectPro File#-------------------------------------------------# # Project created by Qtcreator the- A-29t16:Ten: -##-------------------------------------------------QT-=Core Guitarget=dlldemotemplate=Libconfig+=staticlibsources+=dlldemo.cppheaders+=Dlldemo.hincludepath+ = d:/sdk/opencv/build/Includelibs+ =-ld:/sdk/opencv/build/x86/vc12/Lib-lopencv_calib3d249d-lopencv_contrib249d-lopencv_core249d-lopencv_features2d249d-lopencv_flann249d-lopencv_gpu249d-lopencv_highgu
matrix T, is defined, and the two matrices can be computed by known matching points, just as a single response matrix is obtained.
The following diagram shows the effect of correction
Stereo Matching
Sad matching algorithm
The method is centered on the source matching point of the Zootia image, define a window D, its size (2m+1) (2n+1), statistics its window's gray value, and then in the right image to gradually calculate the gray and the left window of the difference, the last search to th
Image Filtering. The class can is used to apply a arbitrary filtering operation to an image. It contains all the necessary intermediate buffers, it computes extrapolated values of the "virtual" pixels outside of the Image etc. Pointers to the initialized Cv::filterengine instances is returned by various OpenCV functions, such as Cv::createseparab Lelinearfilter (), Cv
In this section, the main learning is through
. Videocapture ()
Call the camera to read the image data, and use the
Cap.set (propid, value) NBSP; Cap.get (propid)
Gets or changes the video properties. Where the value of Propid is 0-18, 19 values are not each can be modified, each value corresponding to the properties and functions as follows:
Parameters
value
function/meaning
Preface
I recently made a digital identification on the card. Call the Caffe module, directly using the Mnist model, but this article does not speak Caffe.
Need to first a series of pretreatment of the picture, the number of cards separated out, a bit of OCR feeling.
I'll write down all the OPENCV functions I use this time. 1. Read the video cv2. Videocapture ()
Parameter 1: Can be a number, corresponding to the camera head number. Can be a video nam
Goal• Learn to read video files, display videos, save video files• Learn to get and display video from the camera• You will learn these functions: Cv2. Videocapture (), Cv2. Videowrite ()Capturing video with the camera
Use the camera to capture a video and convert it into grayscale video.
You should first create a Videocapture object, which can be the index number of the device, or a video file
: https://www.zhihu.com/question/54918332/answer/142137732 First, mean value blur, median blur, user-defined BlurThe code is as follows:#Mean blur, median blur, and custom fuzzy blur are a representation of convolutionImportCv2 as CVImportNumPy as NPdefBlur_demo (image):#mean fuzzy de-random noise has a good effect on drynessDST = Cv.blur (image, (1, 15))#(1, 15) is the vertical direction blur, (15, 1) also horizontal direction blurCv.namedwindow ('Blur_demo',
distribute the monitoring sites to different places. In fact, it is enough to use the nagios distributed method to do this. However, if you want to do an instant trigger emergency task, even if you click execute immediately on the nagios page, it will take a while to return all the results. Therefore, I chose to write a distributed asynchronous system.
The central controller script is as follows:
#!/usr/bin/perluse Modern::Perl;use AnyEvent;use AnyEvent::Redis::RipeRedis;use Storable qw/freeze
training set, and test with the testing set (such as classification).At this point, the error of test set is divided into linear regression linear regression and logistic regression logistic regression two classes:-Error of Linear regression:-The error of logistic regression:===============================Model selection and training, validation of experimental dataFacing model selection problem, how can we get a model of just fit without causing underfit or overfit? We introduce a class of dat
Yes yes, endure the urine to try to update, is to more to the Wuli, of course, the male God in front of the town building, welcome to download map, the specific operation see CodeWulieddie.jpgLogo.pngResults.jpgLoadshowwriteimage.cxx#include #include//#include //#include intMain () {//load image and showCv::mat image = Cv::imread ("wulieddie.jpg"); Cv::namedwindow ("Image");
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