Process camera image in flutter - flutter

Question

I'm trying to process the camera image input in Flutter but I can't seem to get it to work.
I have a listener on the camera feed that launch a function that is supposed to process the images btu everytime I end up doing anything in the function the program interface freeze. My guess is that I have too many frames to process and thus the program freezes but I have no idea how to ignore old frames.
Here is my code so far
import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'package:image/image.dart' as imglib;
import 'package:flutter/scheduler.dart';
import 'user_data_container.dart';
class Camera extends StatefulWidget {
Camera();
#override
_CameraState createState() => new _CameraState();
}
class _CameraState extends State<Camera> {
CameraController controller;
bool isDetecting = false;
double redavg;
imglib.Image last_image;
int count = 0;
Image _image_display;
#override
void initState() {
super.initState();
SchedulerBinding.instance.addPostFrameCallback((_) {
_initializeApp();
});
}
void _initializeApp() async {
var cameras = UserDataContainer.of(context).data.cameras;
if (cameras == null || cameras.length < 1) {
print('No camera is found');
} else {
controller = new CameraController(
cameras[0],
ResolutionPreset.high,
);
controller.initialize().then((_) {
if (!mounted) {
return;
}
setState(() {});
controller.startImageStream((CameraImage img) async {
print(count.toString() + "Stream. detecting: " + isDetecting.toString());
if (!isDetecting) {
isDetecting = true;
int startTime = new DateTime.now().millisecondsSinceEpoch;
_processCameraImage(img);
// int endTime = new DateTime.now().millisecondsSinceEpoch;
// print("Detection done in " + (endTime - startTime).toString());
// isDetecting = false;
}
else{
print("It's detecting");
}
});
});
}
}
#override
void dispose() {
controller?.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
if (controller == null || !controller.value.isInitialized) {
return Container();
}
return
Scaffold(
body: Column(
children: <Widget>[
Text("red: "+ redavg.toString() + " "+ count.toString()),
Expanded(child: last_image == null ? Container() : _image_display),
],
),
);
// );
}
void _processCameraImage(CameraImage image) async {
count = count +1;
print("p: " + image.planes.length.toString());
// if (isDetecting) {
// print("Already detecting;");
// return;
// }
// else{
// isDetecting = true;
try {
await processFrame(image);
} catch (e) {
// await handleExepction(e)
} finally {
print("Done detecting :)");
// isDetecting = false;
}
// }
}
void processFrame(CameraImage image) async {
print ("convert");
imglib.Image convertedImage = await _convertCameraImage(image);
last_image = convertedImage;
imglib.PngEncoder pngEncoder = new imglib.PngEncoder(level: 0, filter: 0);
// Convert to png
List<int> png = pngEncoder.encodeImage(last_image);
_image_display = Image.memory(png);
// var colors = colorAverage(convertedImage);
setState(() {
// redavg = colors[2];
// print(colors.toString());
});
}
imglib.Image _convertCameraImage(CameraImage image) {
int width = image.width;
int height = image.height;
var img = imglib.Image(image.planes[0].bytesPerRow, height); // Create Image buffer
const int hexFF = 0xFF000000;
final int uvyButtonStride = image.planes[1].bytesPerRow;
final int uvPixelStride = image.planes[1].bytesPerPixel;
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
final int uvIndex =
uvPixelStride * (x / 2).floor() + uvyButtonStride * (y / 2).floor();
final int index = y * width + x;
final yp = image.planes[0].bytes[index];
final up = image.planes[1].bytes[uvIndex];
final vp = image.planes[2].bytes[uvIndex];
// Calculate pixel color
int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255);
int g = (yp - up * 46549 / 131072 + 44 - vp * 93604 / 131072 + 91)
.round()
.clamp(0, 255);
int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255);
// color: 0x FF FF FF FF
// A B G R
img.data[index] = hexFF | (b << 16) | (g << 8) | r;
}
}
// Rotate 90 degrees to upright
// var img1 = imglib.copyRotate(img, 90);
imglib.PngEncoder pngEncoder = new imglib.PngEncoder(level: 0, filter: 0);
// Convert to png
List<int> png = pngEncoder.encodeImage(img);
_image_display = Image.memory(png);
return img;
}
}