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 | 1 | initial version |
"Is there some way to activate OpenCV logging in the Java version? " - none of the functions used will throw exceptions(not even in c++), you will have to do manual checks:
import org.opencv.imgproc.*; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.MatOfRect; import org.opencv.core.Point; import org.opencv.core.Rect; import org.opencv.core.Scalar; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.objdetect.CascadeClassifier; // // Detects faces in an image, draws boxes around them, and writes the results // to "faceDetection.png". // class DetectFaceDemo { public void run() { System.out.println("\nRunning DetectFaceDemo"); // Create a face detector from the cascade file in the resources directory: String cascadePath = getClass().getResource("/lbpcascade_frontalface.xml").getPath(); // // i'm unsure, but maybe we should get rid of the whole getClass().getResource()getPath() cruft // in favour of a simple String containing the (absolute) path, like "d:/ocv/lbpcascade_frontalface.xml" // CascadeClassifier faceDetector = new CascadeClassifier(cascadePath);
// sanity check:
if (faceDetector.empty()) {
System.out.println("could not load cascade from " + cascadePath);
}
String imgPath = getClass().getResource("/lena.png").getPath();
Mat image = Imgcodecs.imread(imgPath);
// sanity check:
if (image.empty()) {
System.out.println("could not load image from " + imgPath);
}
// Detect faces in the image.
// MatOfRect is a special container class for Rect.
MatOfRect faceDetections = new MatOfRect();
faceDetector.detectMultiScale(image, faceDetections);
System.out.println(String.format("Detected %s faces", faceDetections.toArray().length));
// Draw a bounding box around each face.
for (Rect rect : faceDetections.toArray()) {
Imgproc.rectangle(image, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 255, 0));
}
// Save the visualized detection.
String filename = "faceDetection.png";
System.out.println(String.format("Writing %s", filename));
boolean ok = Imgcodecs.imwrite(filename, image);
// sanity check:
if (! ok) {
System.out.println("could not save image to " + filename);
}
} } public class HelloOpenCV { public static void main(String[] args) { System.out.println("Hello, OpenCV"); // Load the native library. System.loadLibrary(Core.NATIVE_LIBRARY_NAME); new DetectFaceDemo().run(); } }
| | 2 | No.2 Revision |
"Is there some way to activate OpenCV logging in the Java version? " - none of the functions used will throw exceptions(not even in c++), you will have to do manual checks:
| | 3 | No.3 Revision |
"Is there some way to activate OpenCV logging in the Java version? " - none of the functions used will throw exceptions(not even in c++), you will have to do manual checks:
import org.opencv.imgproc.*;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.objdetect.CascadeClassifier;
//
// Detects faces in an image, draws boxes around them, and writes the results
// to "faceDetection.png".
//
class DetectFaceDemo {
public void run() {
System.out.println("\nRunning DetectFaceDemo");
// Create a face detector from the cascade file in the resources directory:
String cascadePath = getClass().getResource("/lbpcascade_frontalface.xml").getPath();
//
// i'm unsure, but maybe we should get rid of the whole getClass().getResource()getPath() cruft
// in favour of a simple String containing the (absolute) path,
// like "d:/ocv/lbpcascade_frontalface.xml"
//
CascadeClassifier faceDetector = new CascadeClassifier(cascadePath);
// sanity check:
if (faceDetector.empty()) {
System.out.println("could not load cascade from " + cascadePath);
}
String imgPath = getClass().getResource("/lena.png").getPath();
Mat image = Imgcodecs.imread(imgPath);
// sanity check:
if (image.empty()) {
System.out.println("could not load image from " + imgPath);
}
// Detect faces in the image.
// MatOfRect is a special container class for Rect.
MatOfRect faceDetections = new MatOfRect();
faceDetector.detectMultiScale(image, faceDetections);
System.out.println(String.format("Detected %s faces", faceDetections.toArray().length));
// Draw a bounding box around each face.
for (Rect rect : faceDetections.toArray()) {
Imgproc.rectangle(image, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 255, 0));
}
// Save the visualized detection.
String filename = "faceDetection.png";
System.out.println(String.format("Writing %s", filename));
boolean ok = Imgcodecs.imwrite(filename, image);
// sanity check:
if (! ok) {
System.out.println("could not save image to " + filename);
}
}
}
public class HelloOpenCV {
public static void main(String[] args) {
System.out.println("Hello, OpenCV");
// Load the native library.
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new DetectFaceDemo().run();
}
}
| | 4 | No.4 Revision |
"Is there some way to activate OpenCV logging in the Java version? " - none of the functions used will throw exceptions(not even in c++), you will have to do manual checks:
import org.opencv.imgproc.*;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.objdetect.CascadeClassifier;
//
// Detects faces in an image, draws boxes around them, and writes the results
// to "faceDetection.png".
//
class DetectFaceDemo {
public void run() {
System.out.println("\nRunning DetectFaceDemo");
// Create a face detector from the cascade file in the resources directory:
String cascadePath = getClass().getResource("/lbpcascade_frontalface.xml").getPath();
//
// maybe we should get rid of the whole getClass().getResource()getPath() cruft
// in favour of a simple String containing the (absolute) path,
// like "d:/ocv/lbpcascade_frontalface.xml"
//
// also note, that opencv functions cannot read from a zip/jar/apk file,
// so the whole 'resource' approach might be inappropriate.
//
CascadeClassifier faceDetector = new CascadeClassifier(cascadePath);
// sanity check:
if (faceDetector.empty()) {
System.out.println("could not load cascade from " + cascadePath);
}
String imgPath = getClass().getResource("/lena.png").getPath();
Mat image = Imgcodecs.imread(imgPath);
// sanity check:
if (image.empty()) {
System.out.println("could not load image from " + imgPath);
}
// Detect faces in the image.
// MatOfRect is a special container class for Rect.
MatOfRect faceDetections = new MatOfRect();
faceDetector.detectMultiScale(image, faceDetections);
System.out.println(String.format("Detected %s faces", faceDetections.toArray().length));
// Draw a bounding box around each face.
for (Rect rect : faceDetections.toArray()) {
Imgproc.rectangle(image, new Point(rect.x, rect.y),
new Point(rect.x + rect.width, rect.y + rect.height),
new Scalar(0, 255, 0));
}
// Save the visualized detection.
String filename = "faceDetection.png";
System.out.println(String.format("Writing %s", filename));
boolean ok = Imgcodecs.imwrite(filename, image);
// sanity check:
if (! ok) {
System.out.println("could not save image to " + filename);
}
}
}
public class HelloOpenCV {
public static void main(String[] args) {
System.out.println("Hello, OpenCV");
// Load the native library.
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
new DetectFaceDemo().run();
}
}