我用 Chaquopy 制作了 Camerax 应用程序：
- ImageCapture 用例捕获图像（jpg）
- 将其转换为位图
- 将位图转换为字符串
- 将字符串传递给 Python
- Python OpenCV 获取图像分辨率并将其返回给 Android（如字符串）
- 在 Textview 上显示
应用程序正在运行，但问题是：
- 应用程序太慢：15-20 秒（字符串转换？）
- 它显示错误的分辨率（分辨率在 ImageCapture 配置中设置）
- 我怎样才能加快我的应用程序？
- 除了base64字符串之外，还有另一种将图像传递给python的方法吗？
Android CameraAtivity 代码：
'''
public class CameraActivity extends AppCompatActivity {
private PreviewView previewView;
private ImageCapture imageCapture;
private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;
private TextView textView;
private Button button;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
previewView = findViewById(R.id.previewView);
cameraProviderFuture = ProcessCameraProvider.getInstance(this);
textView = findViewById(R.id.length);
button = findViewById(R.id.button);
cameraProviderFuture.addListener(new Runnable() {
@Override
public void run() {
try {
ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
bindImageAnalysis(cameraProvider);
} catch (ExecutionException | InterruptedException e) {
e.printStackTrace();
}
}
}, ContextCompat.getMainExecutor(this));
}
private void bindImageAnalysis(@NonNull ProcessCameraProvider cameraProvider) {
Preview preview = new Preview.Builder().build();
CameraSelector cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK).build();
preview.setSurfaceProvider(previewView.createSurfaceProvider());
Executor cameraexecutor = ContextCompat.getMainExecutor(this);
ImageCapture imageCapture = new ImageCapture.Builder().setTargetResolution(new Size(1200, 1600)).build();
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
imageCapture.takePicture(cameraexecutor, new ImageCapture.OnImageCapturedCallback() {
@Override
public void onCaptureSuccess(@NonNull ImageProxy image){
ByteBuffer byteBuffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[byteBuffer.capacity()];
byteBuffer.get(bytes);
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] imageBytes = baos.toByteArray();
String imgString = Base64.encodeToString(imageBytes, Base64.DEFAULT);
PyObject obj = pythonn(imgString);
textView.setText(obj.toString());
}
@Override
public void onError(@NonNull ImageCaptureException error) {
error.printStackTrace();
}
});
}
});
cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, imageCapture,
preview);
}
private PyObject pythonn(String imgString) {
if(!Python.isStarted())
Python.start(new AndroidPlatform(this ));
Python py = Python.getInstance();
final PyObject pyobj = py.getModule("shape");
PyObject obj = pyobj.callAttr("main",imgString);
return obj;
}
}
'''
Python代码；
import cv2
import numpy as np
import base64
def main(imgString):
decoded_data = base64.b64decode(imgString)
np_data = np.fromstring(decoded_data,np.uint8)
img = cv2.imdecode(np_data,cv2.IMREAD_UNCHANGED)
if img.shape[0] > img.shape[1]:
img = cv2.transpose(img)
return str(str(img.shape[0]) + "_" + str(img.shape[1]))
所有代码都在 Github 上： https ://github.com/kintipu/Camerax_ImageCapture_Chaquopy_OpenCV_ImageResolution/tree/master
2021 年 3 月 29 日更新：我将尝试使用 bytearray，就像 mhsmith 建议的那样。与此同时，我尝试了另一件事：
捕获图像并将其保存为 jpg
然后直接从python中读取图像 App在模拟器中工作，但在真正的手机Android上代码：'''
公共类 CameraActivity 扩展 AppCompatActivity { private PreviewView previewView; 私有图像捕获图像捕获；私有 ListenableFuture cameraProviderFuture；私有文本视图文本视图；私人按钮按钮；私有上下文上下文；
@Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_camera); previewView = findViewById(R.id.previewView); cameraProviderFuture = ProcessCameraProvider.getInstance(this); textView = findViewById(R.id.length); button = findViewById(R.id.button); cameraProviderFuture.addListener(new Runnable() { @Override public void run() { try { ProcessCameraProvider cameraProvider = cameraProviderFuture.get(); bindImageAnalysis(cameraProvider); } catch (ExecutionException | InterruptedException e) { e.printStackTrace(); } } }, ContextCompat.getMainExecutor(this)); } private void bindImageAnalysis(@NonNull ProcessCameraProvider cameraProvider) { Preview preview = new Preview.Builder().build(); CameraSelector cameraSelector = new CameraSelector.Builder() .requireLensFacing(CameraSelector.LENS_FACING_BACK).build(); preview.setSurfaceProvider(previewView.createSurfaceProvider()); Executor cameraexecutor = ContextCompat.getMainExecutor(this); ImageCapture imageCapture = new ImageCapture.Builder().setTargetResolution(new Size(1200, 1600)).build(); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { File file = new File(getBatchDirectoryName(), "photo"+ ".jpg"); ImageCapture.OutputFileOptions outputFileOptions = new ImageCapture.OutputFileOptions.Builder(file).build(); imageCapture.takePicture(outputFileOptions, cameraexecutor, new ImageCapture.OnImageSavedCallback () { @Override public void onImageSaved(@NonNull ImageCapture.OutputFileResults outputFileResults) { new Handler().post(new Runnable() { @Override public void run() { Toast.makeText(CameraActivity.this, "Image Saved successfully" + file.getAbsolutePath(), Toast.LENGTH_LONG).show(); PyObject obj = pythonn(); textView.setText(obj.toString()); } }); } @Override public void onError(@NonNull ImageCaptureException error) { error.printStackTrace(); } }); } }); cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, imageCapture, preview); } public String getBatchDirectoryName() { String app_folder_path = ""; app_folder_path = Environment.getExternalStorageDirectory().toString() + "/images"; File dir = new File(app_folder_path); if (!dir.exists() && !dir.mkdirs()) { } return app_folder_path; } private PyObject pythonn() { if(!Python.isStarted()) Python.start(new AndroidPlatform(this )); Python py = Python.getInstance(); final PyObject pyobj = py.getModule("shape"); PyObject obj = pyobj.callAttr("main"); return obj; }}
'''
Python代码：
'''
import cv2
import numpy as np
from android.os import Environment
path = str(str(Environment.getExternalStorageDirectory()) + "/images" + "/photo.jpg")
def main():
img = cv2.imread(path)
return str(str(img.shape[0]) + "_" + str(img.shape[1]))
'''
2021 年 4 月 4 日更新：
通过一些修改，我让它变得更快：
- 将 bytearray 之类的图像传递给 python（而不是字符串和 base64 转换）-根据 Malcom Smith 的建议
- 位图压缩设置为 JPEG（而不是 PNG）
- Python 从 Create 开始
安卓代码；'''
public class CameraActivity extends AppCompatActivity {
private PreviewView previewView;
private ImageCapture imageCapture;
private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;
private TextView textView;
private Button button;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
previewView = findViewById(R.id.previewView);
cameraProviderFuture = ProcessCameraProvider.getInstance(this);
textView = findViewById(R.id.length);
button = findViewById(R.id.button);
if(!Python.isStarted())
Python.start(new AndroidPlatform(this ));
cameraProviderFuture.addListener(new Runnable() {
@Override
public void run() {
try {
ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
bindImageAnalysis(cameraProvider);
} catch (ExecutionException | InterruptedException e) {
e.printStackTrace();
}
}
}, ContextCompat.getMainExecutor(this));
}
private void bindImageAnalysis(@NonNull ProcessCameraProvider cameraProvider) {
Preview preview = new Preview.Builder().build();
CameraSelector cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK).build();
preview.setSurfaceProvider(previewView.createSurfaceProvider());
Executor cameraexecutor = ContextCompat.getMainExecutor(this);
ImageCapture imageCapture = new ImageCapture.Builder().setTargetResolution(new Size(1200, 1600)).build();
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
imageCapture.takePicture(cameraexecutor, new ImageCapture.OnImageCapturedCallback() {
@Override
public void onCaptureSuccess(@NonNull ImageProxy image){
ByteBuffer byteBuffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[byteBuffer.capacity()];
byteBuffer.get(bytes);
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
// String length = String.valueOf((imgString.length()));
// textView.setText(length);
PyObject obj = pythonn(imageBytes);
textView.setText(obj.toString());
}
@Override
public void onError(@NonNull ImageCaptureException error) {
error.printStackTrace();
}
});
}
});
cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, imageCapture,
preview);
}
private PyObject pythonn(byte[] imageBytes) {
Python py = Python.getInstance();
final PyObject pyobj = py.getModule("shape");
PyObject obj = pyobj.callAttr("main",imageBytes);
return obj;
}
}
Python： '''
import cv2
import numpy as np
def main(imageBytes):
np_data = np.asarray(imageBytes,np.uint8)
img = cv2.imdecode(np_data,cv2.IMREAD_UNCHANGED)
if img.shape[0] > img.shape[1]:
img = cv2.transpose(img)
img = cv2.resize(img, (1600, 1200))
return str(str(img.shape[0]) + "_" + str(img.shape[1]))