Golang : Activate web camera and broadcast out base64 encoded images

For this tutorial, we will learn how to activate web camera with Golang + OpenCV and stream out base64 encoded images via HTTP server. This tutorial is derived from the lesson that I use to teach my son on the subject of computer vision and Golang. It is based on the Go-OpenCV tutorial on activating web camera (https://github.com/lazywei/go-opencv/blob/master/samples/webcam.go).

The program will activate the web camera when you point your web browser to localhost:8080 and begin streaming out base64 encoded images. You will have to scroll down the see the new images. LOL! Good enough to get a 3 years old kid excited about computer vision.

Before you start.

go get github.com/lazywei/go-opencv

Here you go!

 package main

 import (

 func broadcast(w http.ResponseWriter, r *http.Request) {
  webCamera := opencv.NewCameraCapture(0)

  if webCamera == nil {
 panic("Unable to open camera")

  defer webCamera.Release()

  for {
 if webCamera.GrabFrame() {
 imgFrame := webCamera.RetrieveFrame(1)
 if imgFrame != nil {

 // convert IplImage(Intel Image Processing Library)
 // to image.Image
 goImgFrame := imgFrame.ToImage()

 // and then convert to []byte
 // with the help of png.Encode() function

 frameBuffer := new(bytes.Buffer)
 //frameBuffer := make([]byte, imgFrame.ImageSize())
 err := png.Encode(frameBuffer, goImgFrame)

 if err != nil {

 // convert the buffer bytes to base64 string - use buf.Bytes() for new image
 imgBase64Str := base64.StdEncoding.EncodeToString(frameBuffer.Bytes())

 // Embed into an html without PNG file
 img2html := "<html><body><img src=\"data:image/png;base64," + imgBase64Str + "\" /></body></html>"


 // TODO :
 // encode frames to stream via WebRTC




 func main() {
  mux := http.NewServeMux()
  mux.HandleFunc("/", broadcast)
  http.ListenAndServe(":8080", mux)

streaming out base64 encoded images to browser

streaming out base64 encoded images to browser


In case you get these error messages :

No package 'opencv' found

Package opencv was not found in the pkg-config search path.

Perhaps you should add the directory containing `opencv.pc'

to the PKGCONFIGPATH environment variable

Fix this problem by installing openCV.

On MacOSX :

>brew install homebrew/science/opencv






  See also : Golang : Save webcamera frames to video file

By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.