Golang : Fix opencv.LoadHaarClassifierCascade The node does not represent a user object error
Problem:
You're trying load a Haarcascade file with opencv.LoadHaarClassifierCascade()
function in Golang, but you get this error message instead :
OpenCV Error: Unspecified error (The node does not represent a user object (unknown type?)) in cvRead, file /tmp/opencv-20170224-77195-1rw28s/opencv-2.4.13.2/modules/core/src/persistence.cpp, line 5008
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /tmp/opencv-20170224-77195-1rw28s/opencv-2.4.13.2/modules/core/src/persistence.cpp:5008: error: (-2) The node does not represent a user object (unknown type?) in function cvRead
package main
import (
"fmt"
"github.com/lazywei/go-opencv/opencv"
)
var faceCascade = new(opencv.HaarCascade)
var eyeCascade = new(opencv.HaarCascade)
func main() {
faceCascade = opencv.LoadHaarClassifierCascade("haarcascade_frontalface_alt.xml")
defer faceCascade.Release()
fmt.Println(faceCascade) // ---- ok
eyeCascade = opencv.LoadHaarClassifierCascade("haarcascade_eye.xml") // --- will crash.
defer eyeCascade.Release()
fmt.Println(eyeCascade)
}
What's going on and how to fix this issue?
Solution:
If you try to load the haarcascade_eye.xml
file that you've downloaded from https://github.com/opencv/opencv/tree/master/data/haarcascades, you will still encounter the same error message. What you need to do is to download the Open CV 2.4.9 version from http://opencv.org/downloads.html and retrieve the haarcascade_eye.xml
from /data/haarcascades
folder.
Pretty sure it is a bug somewhere in OpenCV code.
References:
See also : Golang : Tell color name with OpenCV example
By Adam Ng
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