对OpenCV的FaceRecognizer有信心吗? [英] What is confidence in OpenCV's FaceRecognizer?

问题描述

我一直在使用OpenCV的FaceRecognizer进行人脸识别项目，进行性别区分.该算法效果很好，但是我想在程序中实现一些额外的功能，例如预测的可信度.

I've been working on a face recognition project using OpenCV's FaceRecognizer, doing gender differentiation. The algorithm works pretty well, but I wanted to implement some extra features into my program like the confidence of the prediction.

预测函数可以输出置信度，但是我不确定它的含义.这种信心实际上可以衡量什么，我可以将其转换为百分比吗?

The predict function can output a confidence level, but I'm not sure what it means. What does this confidence actually measure, and can I convert it into a percentage?

int predictedLabel = -1;
double confidence = 0.0;
model->predict(face_resized, predictedLabel, confidence);
string result_message = format("Predicted class = %d / Confidence = %d.", predictedLabel, confidence);
cout << result_message << endl;

这是输出的样子. https://www.dropbox.com/s/65h1n5180ulz3hl/facerecConfidence%20.jpg

推荐答案

在OpenCV-用户列表此处.

There's a brief discussion on what this distance actually is on the OpenCV-users list here.

总结一下，他们使用的功能是:

To summarise, the function they use is:

distance = 1.0f - sqrt( distSq / (float)(nTrainFaces * nEigens) ) / 255.0f 

但是，该函数的作者说这是一个非常粗糙的指南，而不是一个完整的证明指南.请参阅用户列表讨论的链接，以获取对本文的参考以及对​​替代指标的建议.

However, the author of the function says that it is a very rough guide and not a full proof guide. See the link to the users list discussion for a reference to the paper and a suggestion for an alternative metric.

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