如何检测视图内的条形码角点？
问题描述 投票：0回答：1
我的条码阅读器运行良好，但我希望用户只能扫描视图区域内的条码以进行检测。我为它写了一个代码。我可以获得
cornerPointsrectview
BarcodeReaderFragment.kt
val imageAnalyzer = ImageAnalysis.Builder()
.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
.build()
.also {
val rect = Rect()
binding.viewFocusArea.getGlobalVisibleRect(rect)
it.setAnalyzer(
cameraExecutor, BarcodeAnalyzer(
rect,
::barcodeListener
)
)
}
BarcodeAnalyzer.kt
class BarcodeAnalyzer(
private val rectArea: Rect,
private val barcodeListener: (barcode: String) -> Unit
) : ImageAnalysis.Analyzer {
.addOnCompleteListener {
image.close()
if (it.isSuccessful) {
val barcodes = it.result as List<Barcode>
// Task completed successfully
for (barcode in barcodes) {
val cornerTL = barcode.cornerPoints?.get(0)
val cornerTR = barcode.cornerPoints?.get(1)
val cornerBL = barcode.cornerPoints?.get(2)
val cornerBR = barcode.cornerPoints?.get(3)
cornerTL?.let { topLeft ->
cornerTR?.let { topRight ->
cornerBR?.let { bottomRight ->
cornerBL?.let { bottomLeft ->
if (rectArea.contains(topLeft) && rectArea.contains(topRight) && rectArea.contains(bottomRight) && rectArea.contains(
bottomLeft
)
) {
barcodeListener(barcode.rawValue ?: "")
}
}
}
fragment_barcode_reader.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.camera.view.PreviewView
android:id="@+id/preview_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<View
android:id="@+id/viewRightTopVCorner"
android:layout_width="12dp"
android:layout_height="1dp"
android:layout_marginEnd="-4dp"
android:layout_marginBottom="5dp"
android:background="@color/white"
app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
app:layout_constraintEnd_toEndOf="@+id/viewFocusArea" />
<View
android:id="@+id/viewRightTopHCorner"
android:layout_width="1dp"
android:layout_height="12dp"
android:background="@color/white"
app:layout_constraintEnd_toEndOf="@+id/viewRightTopVCorner"
app:layout_constraintTop_toBottomOf="@+id/viewRightTopVCorner" />
<View
android:id="@+id/viewRightBottomVCorner"
android:layout_width="12dp"
android:layout_height="1dp"
android:layout_marginTop="5dp"
android:layout_marginEnd="-4dp"
android:background="@color/white"
app:layout_constraintEnd_toEndOf="@+id/viewFocusArea"
app:layout_constraintTop_toBottomOf="@+id/viewFocusArea" />
<View
android:id="@+id/viewRightBottomHCorner"
android:layout_width="1dp"
android:layout_height="12dp"
android:background="@color/white"
app:layout_constraintEnd_toEndOf="@+id/viewRightBottomVCorner"
app:layout_constraintBottom_toTopOf="@+id/viewRightBottomVCorner" />
<View
android:id="@+id/viewLeftBottomVCorner"
android:layout_width="12dp"
android:layout_height="1dp"
android:layout_marginStart="-4dp"
android:layout_marginTop="5dp"
android:background="@color/white"
app:layout_constraintStart_toStartOf="@+id/viewFocusArea"
app:layout_constraintTop_toBottomOf="@+id/viewFocusArea" />
<View
android:id="@+id/viewLeftBottomHCorner"
android:layout_width="1dp"
android:layout_height="12dp"
android:background="@color/white"
app:layout_constraintBottom_toTopOf="@+id/viewLeftBottomVCorner"
app:layout_constraintStart_toStartOf="@+id/viewLeftBottomVCorner" />
<View
android:id="@+id/viewLeftTopVCorner"
android:layout_width="12dp"
android:layout_height="1dp"
android:layout_marginStart="-4dp"
android:layout_marginBottom="5dp"
android:background="@color/white"
app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
app:layout_constraintStart_toStartOf="@+id/viewFocusArea" />
<View
android:id="@+id/viewLeftTopHCorner"
android:layout_width="1dp"
android:layout_height="12dp"
android:background="@color/white"
app:layout_constraintTop_toBottomOf="@+id/viewLeftTopVCorner"
app:layout_constraintStart_toStartOf="@+id/viewLeftTopVCorner" />
<View
android:id="@+id/viewFocusArea"
android:layout_width="0dp"
android:layout_height="101dp"
android:layout_marginStart="48dp"
android:layout_marginTop="35dp"
android:layout_marginEnd="47dp"
android:background="#00FFFFFF"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/preview_view"
app:layout_constraintTop_toBottomOf="@+id/txtBarcodeScan" />
<View
android:id="@+id/shadow_top"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="-4dp"
android:background="#80000000"
app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
app:layout_constraintEnd_toStartOf="@+id/shadow_right"
app:layout_constraintStart_toEndOf="@+id/shadow_left"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="invisible" />
<View
android:id="@+id/shadow_bottom"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="-4dp"
android:background="#80000000"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@+id/shadow_right"
app:layout_constraintStart_toEndOf="@+id/shadow_left"
app:layout_constraintTop_toBottomOf="@+id/viewFocusArea"
tools:visibility="invisible" />
<View
android:id="@+id/shadow_left"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginEnd="-4dp"
android:background="#80000000"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@+id/viewFocusArea"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="invisible" />
<View
android:id="@+id/shadow_right"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="-4dp"
android:background="#80000000"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="@+id/preview_view"
app:layout_constraintStart_toEndOf="@+id/viewFocusArea"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="invisible" />
<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
app:layout_constraintEnd_toEndOf="@+id/preview_view"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_identity_hexagon" />
<TextView
android:id="@+id/txtBarcodeScan"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="Lütfen fiyatını öğrenmek istediğin \nürünün barkodunu okut"
android:textColor="@color/white"
android:gravity="center"
android:fontFamily="@font/poppins_regular"
android:textSize="16sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/image" />
<com.google.android.material.button.MaterialButton
android:id="@+id/btnChangeShop"
style="@style/Widget.MaterialComponents.Button.TextButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="55dp"
android:backgroundTint="@color/dull_orange"
android:fontFamily="@font/poppins_semibold"
android:insetTop="0dp"
android:insetBottom="0dp"
android:letterSpacing="0"
app:cornerRadius="4dp"
android:paddingVertical="15dp"
android:text="@string/click_to_change_shop"
android:textAllCaps="false"
android:textColor="@color/white"
android:textSize="14sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
1个回答
1
投票
投票
以防万一你还需要它。
我已经编写了一个片段来测试 imageProxy 坐标到预览坐标的转换，使用在以下位置找到的片段的 Java 版本：https://developer.android.com/training/camerax/transform-output.
当其视图进入位于高度 = previewView.getHeight()/5 和宽度 = preview.getWidth()/2 的矩形视图时，条形码被检测到。
结论：检测效果很好。
@SuppressLint("SetTextI18n")
@Override
public void analyze(@NonNull ImageProxy imageProxy) {
Image mediaImage = imageProxy.getImage();
int rotation = imageProxy.getImageInfo().getRotationDegrees();
if (mediaImage != null) {
InputImage image =
InputImage.fromMediaImage(mediaImage, rotation);
scanner.process(image)
.addOnSuccessListener(barcodes -> {
for (Barcode barcode : barcodes) {
processBarcodeResult(barcode, imageProxy);
}
})
.addOnCompleteListener(results -> imageProxy.close());
}
}
static void processBarcodeResult(Barcode barcode, ImageProxy imageProxy) {
// xp and yp are the coordinates of the center of the preview rectangle
int xp = previewView.getWidth() >> 1;
int yp = previewView.getHeight() / 5;
// xOffset and yOffset are threshold for detecting
// that the barcode view enters the preview rectangle
int xOffset = (int) (barcode.getBoundingBox().width() / 2.5f);
int yOffset = (int) (barcode.getBoundingBox().height() / 2.5f);
// xb and yb are the coordinates of the center
// of the barcode boundingbox.
int xb = barcode.getBoundingBox().centerX();
int yb = barcode.getBoundingBox().centerY();
// matrix transforms the imageProxy coordinates in the
// preview coordinates
Matrix matrix = getMappingMatrix(imageProxy);
float[] xyb = new float[]{xb, yb};
matrix.mapPoints(xyb);// transforms the bounding box center
// coordinates
xb = (int) xyb[0];
yb = (int) xyb[1];
if (xb > xp - xOffset && xb < xp + xOffset && yb > yp - yOffset && yb < yp + yOffset) {
format.setText(barcode.getFormat() + "");
code.setText(barcode.getRawValue());
// code and format are 2 TextView in the mainactivity layout.
}
}
static Matrix getMappingMatrix(ImageProxy imageProxy) {
Rect cropRect = imageProxy.getCropRect();
Matrix matrix = new Matrix();
// A float array of the source vertices (crop rect) in clockwise order.
float[] source = {cropRect.left, cropRect.top, cropRect.right,
cropRect.top, cropRect.right, cropRect.bottom, cropRect.left,
cropRect.bottom
};
// A float array of the destination vertices in clockwise order.
float[] destination = {0f, 0f, previewView.getWidth(), 0f,
previewView.getWidth(), previewView.getHeight(), 0f,
previewView.getHeight()
};
// The destination vertexes need to be shifted based on rotation degrees.
// The rotation degree represents the clockwise rotation needed to correct
// the image.
// Each vertex is represented by 2 float numbers in the vertices array.
int vertexSize = 2;
// The destination needs to be shifted 1 vertex for every 90° rotation.
// imageProxy is already rotated => rotationDegrees = 0!
int rotationDegrees = 0;
int shiftOffset = rotationDegrees / 90 * vertexSize;
float[] tempArray = destination.clone();
for (int toIndex = 0; toIndex < source.length; toIndex++) {
int fromIndex = (toIndex + shiftOffset) % source.length;
destination[toIndex] = tempArray[fromIndex];
}
matrix.setPolyToPoly(source, 0, destination, 0, 4);
return matrix;
}
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