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// What it does:
//
// This example uses the CascadeClassifier class to detect faces,
// and draw a rectangle around each of them, before displaying them within a Window.
//
// How to run:
//
// facedetect [camera ID] [classifier XML file]
//
// go run ./cmd/facedetect/main.go 0 data/haarcascade_frontalface_default.xml
//
// +build example
package main
import (
"fmt"
"image"
"image/color"
"os"
"gocv.io/x/gocv"
)
func main() {
if len(os.Args) < 3 {
fmt.Println("How to run:\n\tfacedetect [camera ID] [classifier XML file]")
return
}
// parse args
deviceID := os.Args[1]
xmlFile := os.Args[2]
// open webcam
webcam, err := gocv.OpenVideoCapture(deviceID)
if err != nil {
fmt.Printf("error opening video capture device: %v\n", deviceID)
return
}
defer webcam.Close()
// open display window
window := gocv.NewWindow("Face Detect")
defer window.Close()
// prepare image matrix
img := gocv.NewMat()
defer img.Close()
// color for the rect when faces detected
blue := color.RGBA{0, 0, 255, 0}
// load classifier to recognize faces
classifier := gocv.NewCascadeClassifier()
defer classifier.Close()
if !classifier.Load(xmlFile) {
fmt.Printf("Error reading cascade file: %v\n", xmlFile)
return
}
fmt.Printf("Start reading device: %v\n", deviceID)
for {
if ok := webcam.Read(&img); !ok {
fmt.Printf("Device closed: %v\n", deviceID)
return
}
if img.Empty() {
continue
}
// detect faces
rects := classifier.DetectMultiScale(img)
fmt.Printf("found %d faces\n", len(rects))
// draw a rectangle around each face on the original image,
// along with text identifing as "Human"
for _, r := range rects {
gocv.Rectangle(&img, r, blue, 3)
size := gocv.GetTextSize("Human", gocv.FontHersheyPlain, 1.2, 2)
pt := image.Pt(r.Min.X+(r.Min.X/2)-(size.X/2), r.Min.Y-2)
gocv.PutText(&img, "Human", pt, gocv.FontHersheyPlain, 1.2, blue, 2)
}
// show the image in the window, and wait 1 millisecond
window.IMShow(img)
if window.WaitKey(1) >= 0 {
break
}
}
}