diff --git a/app/src/main/cpp/PhoneDevice.cpp b/app/src/main/cpp/PhoneDevice.cpp
index 2e60a9aa..0ddbee47 100644
--- a/app/src/main/cpp/PhoneDevice.cpp
+++ b/app/src/main/cpp/PhoneDevice.cpp
@@ -2544,14 +2544,6 @@ void CPhoneDevice::CloseCamera2(CPhoneDevice::CPhoneCamera* camera, unsigned int
 
 }
 
-void visualize(const char* filename, const ncnn::Mat& m)
-{
-    cv::Mat a(m.h, m.w, CV_8UC3);
-    m.to_pixels(a.data, ncnn::Mat::PIXEL_BGR2RGB);
-
-    cv::imwrite(filename, a);
-}
-
 void DrawOutlineText(cv::Ptr<cv::ft::FreeType2> ft2, cv::Mat& mat, const std::string& str, cv::Point startPoint, int fontSize, cv::Scalar clr, int thickness)
 {
     if (mat.empty())