Tag: open-source

[OpenCV] detectMultiScale: output detection score

OpenCV provides quite decent implementation of the Viola-Jones Face detector. A quick example looks like this (OpenCV 2.4.5 tested): // File: main.cc #include using namespace cv; int main(int argc, char **argv) { CascadeClassifier cascade; const float scale_factor(1.2f); const int min_neighbors(3); if (cascade.load("./lbpcascade_frontalface.xml")) { for (int i = 1; i < argc; i++) { Mat img

iOS逐帧处理录像-MPVideoProcessor

一般在iOS上做录像都可以直接使用UIImagePickerController。 但有时候难免需要做逐帧的处理,比如实时的滤镜之类的。 参照这个帖子: A (quasi-) real-time video processing on iOS 把使用AVFoundation做录像的代码,做了一个简单的封装。 Delegate可以得到逐帧的彩色或者灰度图,然后就可以加上自己需要的处理了。 代码放在Gihub上:MPVideoProcessor 具体使用请参见Github上的Readme.

Draw ROC Curve

A piece of fairly simple Matlab script to draw the ROC Curve from an array of scores and an array of labels. function [Tps, Fps] = ROC(scores, labels) %% Sort Labels and Scores by Scores sl = [scores; labels]; [d1 d2] = sort(sl(1,:)); sorted_sl = sl(:,d2); s_scores = sorted_sl(1,:); s_labels = round(sorted_sl(2,:)); %% Constants counts