flutter_camera_calibration #

"flutter_camera_calibration plugin project"

1. Introduction #

• The flutter_camera_calibration plugin project provides camera calibration functionality for iOS and Android using the OpenCV 4.3.0 library.

  It allows you to obtain the camera's intrinsic parameters.

• This functionality is achieved by adapting the C++ camera calibration code provided in the OpenCV tutorials for use in Flutter.

  The project uses the FFI (Foreign Function Interface) library to bind these C++ functions for use in Flutter.

• In the example code, you will notice the usage of both file_picker and image_picker.

  Additionally, you can download the configuration file and test images from the following link:

  https://github.com/deokgyuhan/flutter_camera_calibration/tree/master/ScreenShots/data

2. Screenshots #

3. Setup #

• The permission settings required for file_picker and image_picker can be found in the respective plugin installation documentation for iOS and Android.

4. Usage #

import 'package:flutter_camera_calibration/flutter_camera_calibration.dart' as flutter_camera_calibration;

//get opencv version
var version = flutter_camera_calibration.opencvVersion();

//get camera intrinsic parameter begin
String? filePath = ""; 
String full_path = "";   //config file path

//select config file 'in_VID5.xml'
FilePickerResult? result = await FilePicker.platform.pickFiles();
if (result != null) {
filePath =  result.files.single.path;
full_path = filePath.toString();
if(filePath != null) {
 // print("------------->"+filePath); 
}
} else {
// User canceled the picker
}

//select Captured images
final List<XFile>? images = await _picker.pickMultiImage();
final List<String> imagePaths = [];

if(images != null) {
for (final image in images) {
final imagePath = image?.path ?? "none";
// print("-----------"+imagePath.toString());
imagePaths.add(imagePath);
}
}

//get camera intrinsic parameter begin
final calibration_result = await flutter_camera_calibration.cameraCalibrate(full_path, imagePaths);

var matrix = flutter_camera_calibration.CameraIntrincMatrix(
  calibration_result.rows,
  calibration_result.cols,
  calibration_result.array,
);

print(matrix);
//get camera intrinsic parameter end

- Reference - #

• Source: Translated from the official OpenCV documentation.

• OpenCV Camera Calibration Example: https://docs.opencv.org/4.3.0/d4/d94/tutorial_camera_calibration.html

• file picker: https://pub.dev/packages/file_picker

• image picker: https://pub.dev/packages/image_picker