Golang implements image thumbnail generation and face detection methods

Golang’s method of implementing image thumbnail generation and face detection

Abstract:
This article introduces the use of Golang to achieve image thumbnail generation and face detection method. First, we will generate thumbnails through Golang's image processing library and save the thumbnails to the local disk. Then, we will introduce how to use Golang's face detection library to detect faces in the generated thumbnails and return the detection results.

1. Image thumbnail generation:
   First, we need to use Golang's image processing library to generate thumbnails. We can use third-party libraries such as "github.com/nfnt/resize" to achieve this. Here is a sample code that demonstrates how to generate a thumbnail:

package main

import (
    "fmt"
    "image"
    "image/jpeg"
    "log"
    "os"

    "github.com/nfnt/resize"
)

func main() {
    inFile, err := os.Open("input.jpg")
    if err != nil {
        log.Fatal(err)
    }
    defer inFile.Close()

    // Decode the image
    srcImg, _, err := image.Decode(inFile)
    if err != nil {
        log.Fatal(err)
    }

    // Resize the image
    thumbnail := resize.Resize(200, 0, srcImg, resize.Lanczos3)

    // Create a new file for the thumbnail
    outFile, err := os.Create("thumbnail.jpg")
    if err != nil {
        log.Fatal(err)
    }
    defer outFile.Close()

    // Encode the thumbnail to JPEG format
    err = jpeg.Encode(outFile, thumbnail, &jpeg.Options{jpeg.DefaultQuality})
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println("Thumbnail generated successfully!")
}

This code first opens an image file named "input.jpg" and decodes it. Then, use the resize library to scale the image to a certain size (width 200 pixels in this example, height calculated automatically). After that, save the generated thumbnail to a file named "thumbnail.jpg". Finally, a prompt message indicating successful thumbnail generation is output.

2. Face Detection:
   Next, we will introduce how to use Golang’s face detection library to detect faces in the generated thumbnails. We can use the third-party library "github.com/esimov/stackblur-go" for image blur processing, and then use another third-party library "github.com/Kagami/go-face" for face detection. Here is a sample code that demonstrates how to detect faces in thumbnails:

package main

import (
    "fmt"
    "image"
    "image/jpeg"
    "log"
    "os"

    "github.com/esimov/stackblur-go"
    "github.com/Kagami/go-face"
)

func main() {
    // Load the face detection model
    model, err := face.NewRecognizer("models")
    if err != nil {
        log.Fatal(err)
    }
    defer model.Close()

    // Open the thumbnail image file
    inFile, err := os.Open("thumbnail.jpg")
    if err != nil {
        log.Fatal(err)
    }
    defer inFile.Close()

    // Decode the thumbnail image
    srcImg, _, err := image.Decode(inFile)
    if err != nil {
        log.Fatal(err)
    }

    // Blur the image for better face detection results
    stackblur.Process(srcImg, uint32(srcImg.Bounds().Dx()), uint32(srcImg.Bounds().Dy()), 20)

    // Convert the image to grayscale
    grayImg, err := face.ConvertImageToGray(srcImg)
    if err != nil {
        log.Fatal(err)
    }

    // Detect faces in the image
    faces, err := model.Recognize(grayImg, 1.5, 3)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("Detected %d face(s) in the thumbnail
", len(faces))

    // Draw rectangles around the detected faces
    for _, f := range faces {
        x, y, w, h := f.Rectangle()
        faceImg := face.Crop(grayImg, face.Rect(x, y, x+w, y+h))
        outFile, err := os.Create("face.jpg")
        if err != nil {
            log.Fatal(err)
        }
        defer outFile.Close()

        // Encode the face image to JPEG format
        err = jpeg.Encode(outFile, faceImg, &jpeg.Options{jpeg.DefaultQuality})
        if err != nil {
            log.Fatal(err)
        }

        fmt.Printf("Face detected at coordinates (%d,%d,%d,%d)
", x, y, w, h)
    }
}

This code first loads the face detection model and opens a file called "thumbnail.jpg" Image files. Then, the thumbnails are blurred and grayscale converted to improve the accuracy of the face detection results. Next, use a face detection library to detect faces in the thumbnails and output the number of detected faces. Finally, the detected faces are marked in the form of rectangular boxes and saved to a file named "face.jpg".

Summary:
This article introduces how to use Golang to achieve image thumbnail generation and face detection. Through the support of third-party libraries, we can easily implement these functions in Golang. Using these techniques, we can process images and extract useful information from them, such as generating thumbnails and detecting faces. I hope this article can be helpful to you, thank you for reading!

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