如何将CameraImage保存到图像文件中？
如何将CameraImage保存到图像文件中？
提问于 2019-11-20 12:10:49
我开发了一个带有颤振的移动应用程序。我做对象检测使用"controller.startImageStream“，这种方法返回CameraImage，而我用的是对象检测。我想保存这个图像文件。为了保存，我尝试将此文件转换为List和jpg文件。但uint8list无法转换为List。这种结构是真正的方式吗？如果你对我的问题有不同的解决方案，请与我分享。
这是我的视频流方法；
startVideoStreaming() {
if (cameras == null || cameras.length < 1) {
print('No camera is found');
} else {
controller = new CameraController(
cameras[0],
ResolutionPreset.medium,
);
if(!_busy){
controller.initialize().then((_) {
print("model yükleme bitmiş stream dinleme başlıyor ");
controller.startImageStream((CameraImage img){
print("img format: ${img.format} planes: ${img.planes}");
List<int> imageBytes = [];
img.planes.map((plane) {
imageBytes.addAll(plane.bytes.toList());
});
// call save image file method
saveImageFile(imageBytes).then((res) => {
print("save image file successfull filepath: $res")
}).catchError((err) => {
print("error on save image file error: $err")
});
if(!isDetecting){
isDetecting = true;
print("Tflite'a stream gönderildi");
Tflite.detectObjectOnFrame(
bytesList: img.planes.map((plane) {
return plane.bytes;
}).toList(),
model: "SSDMobileNet",
imageHeight: img.height,
imageWidth: img.width,
imageMean: 127.5,
imageStd: 127.5,
numResultsPerClass: 1,
threshold: 0.4,
).then((recognitions) {
int endTime = new DateTime.now().millisecondsSinceEpoch;
setState(() {
_recognitions=recognitions;
});
print("Recognitions: $recognitions");
isDetecting = false;
});
}
});
});
}
}
}这是我的形象保存方法；
Future<String> saveImageFile(imageBytes) async {
final Directory extDir = await getApplicationDocumentsDirectory();
final String dirPath = '${extDir.path}/Pictures/flutter_test';
await Directory(dirPath).create(recursive: true);
final String filePath = '$dirPath/${timestamp()}.jpg';
if (controller.value.isTakingPicture) {
// A capture is already pending, do nothing.
return null;
}
try {
File file = new File(filePath);
file.writeAsBytes(imageBytes);
print("finish image saved $imageBytes");
} on CameraException catch (e) {
_showCameraException(e);
return null;
}
return filePath;
}回答 4
Stack Overflow用户
回答已采纳
发布于 2019-11-21 03:38:25
可以使用以下代码片段将CameraImage YUV420或BGRA8888转换为图像
gist的代码：https://gist.github.com/Alby-o/fe87e35bc21d534c8220aed7df028e03
// imgLib -> Image package from https://pub.dartlang.org/packages/image
import 'package:image/image.dart' as imglib;
import 'package:camera/camera.dart';
Future<List<int>> convertImagetoPng(CameraImage image) async {
try {
imglib.Image img;
if (image.format.group == ImageFormatGroup.yuv420) {
img = _convertYUV420(image);
} else if (image.format.group == ImageFormatGroup.bgra8888) {
img = _convertBGRA8888(image);
}
imglib.PngEncoder pngEncoder = new imglib.PngEncoder();
// Convert to png
List<int> png = pngEncoder.encodeImage(img);
return png;
} catch (e) {
print(">>>>>>>>>>>> ERROR:" + e.toString());
}
return null;
}
// CameraImage BGRA8888 -> PNG
// Color
imglib.Image _convertBGRA8888(CameraImage image) {
return imglib.Image.fromBytes(
image.width,
image.height,
image.planes[0].bytes,
format: imglib.Format.bgra,
);
}
// CameraImage YUV420_888 -> PNG -> Image (compresion:0, filter: none)
// Black
imglib.Image _convertYUV420(CameraImage image) {
var img = imglib.Image(image.width, image.height); // Create Image buffer
Plane plane = image.planes[0];
const int shift = (0xFF << 24);
// Fill image buffer with plane[0] from YUV420_888
for (int x = 0; x < image.width; x++) {
for (int planeOffset = 0;
planeOffset < image.height * image.width;
planeOffset += image.width) {
final pixelColor = plane.bytes[planeOffset + x];
// color: 0x FF FF FF FF
// A B G R
// Calculate pixel color
var newVal = shift | (pixelColor << 16) | (pixelColor << 8) | pixelColor;
img.data[planeOffset + x] = newVal;
}
}
return img;
}Stack Overflow用户
发布于 2019-11-20 13:11:04
去做吧
var temp = new Uint8List(500);
var list = new List.from(temp);
Stack Overflow用户
发布于 2021-11-22 11:19:52
颤振现在有了将List<int>转换为Uint8List的方法。您可以使用以下内容：
Uint8List.fromList(List<int> elements);请参阅https://api.flutter.dev/flutter/dart-typed_data/Uint8List/Uint8List.fromList.html
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/58954057
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