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decrease image resolution in java
(4 answers)
Closed 8 years ago.
can any one help me..?
I have some .jpg's created from JPanel. Unfortunately its DPI is 72. Is there a programmatic way to change the DPI of these .jpg's ?
Now i use following code for change DPI. But it have some issues when i try to build project.
`JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(new FileOutputStream(outfile));
JPEGEncodeParam jpegEncodeParam = jpegEncoder.getDefaultJPEGEncodeParam(image);
jpegEncodeParam.setDensityUnit(JPEGEncodeParam.DENSITY_UNIT_DOTS_INCH);
jpegEncodeParam.setXDensity(300);
jpegEncodeParam.setYDensity(300);
jpegEncoder.encode(image, jpegEncodeParam);`
Thanks in advance :)
You can scale an image using Graphics2D methods (from java.awt). This tutorial at http://www.mkyong.com/java/how-to-resize-an-image-in-java explains it in depth.
here is an example
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.net.*;
import javax.imageio.*;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.Image;
import java.io.File;
import java.io.FileOutputStream;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.stream.FileImageInputStream;
import javax.swing.ImageIcon;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class ImageManipulation {
public static void main(String[] args) throws Exception {
File infile = new File("/your image.jpg");
File outfile = new File("/your image.jpg");
ImageReader reader = ImageIO.getImageReadersByFormatName("jpeg").next();
reader.setInput(new FileImageInputStream(infile), true, false);
IIOMetadata data = reader.getImageMetadata(0);
BufferedImage image = reader.read(0);
int w = 600, h = -1;
Image rescaled = image.getScaledInstance(w, h, Image.SCALE_AREA_AVERAGING);
BufferedImage output = toBufferedImage(rescaled, BufferedImage.TYPE_INT_RGB);
Element tree = (Element) data.getAsTree("javax_imageio_jpeg_image_1.0");
Element jfif = (Element) tree.getElementsByTagName("app0JFIF").item(0);
for (int i = 0; i < jfif.getAttributes().getLength(); i++) {
Node attribute = jfif.getAttributes().item(i);
System.out.println(attribute.getNodeName() + "="
+ attribute.getNodeValue());
}
FileOutputStream fos = new FileOutputStream(outfile);
JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(fos);
JPEGEncodeParam jpegEncodeParam = jpegEncoder.getDefaultJPEGEncodeParam(output);
jpegEncodeParam.setDensityUnit(JPEGEncodeParam.DENSITY_UNIT_DOTS_INCH);
jpegEncodeParam.setXDensity(300);
jpegEncodeParam.setYDensity(300);
jpegEncoder.encode(output, jpegEncodeParam);
fos.close();
}
public static BufferedImage toBufferedImage(Image image, int type) {
int w = image.getWidth(null);
int h = image.getHeight(null);
BufferedImage result = new BufferedImage(w, h, type);
Graphics2D g = result.createGraphics();
g.drawImage(image, 0, 0, null);
g.dispose();
return result;
}
}
There is a similar question about resolution, answered in the following SO question here.
In general, you may be interested in learning image processing algorithms, which are described here:
The basic concept in decreasing resolution is that you are selectively
deleting data from the image.
Related
I am new to image processing in java and I am trying to convert an image to stencil (I think stencil is name given for it!).
The input image is this:-
After processing the image would be like this:-
I searched google. But could find a solution. (maybe because I don't know what is the actual name of this process.)
Is this possible with java?
Yes I found the solution. if we Binarize an image it will work.
Input image:-
Output Image:-
Code:-
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
public class Main {
public static void main(String[] args) throws IOException {
BufferedImage bi = ImageIO.read(new File("D:\\IMG_20211029_124954.jpg"));
ImageIO.write(binarizeImage(bi), "png", new File("D:\\1.png"));
}
public static BufferedImage binarizeImage(BufferedImage img_param)
{
BufferedImage image = new BufferedImage(
img_param.getWidth(),
img_param.getHeight(),
BufferedImage.TYPE_BYTE_BINARY
);
Graphics g = image.getGraphics();
g.drawImage(img_param, 0, 0, null);
g.dispose();
return image;
}
}
To make the image transparent , You can do something like this:-
for(int i=0;i<img.width;i++){
for(int j=0;j<img.height;j++){
Color c = new Color(255,255,255,0);
if(img.getRGB==Color.white.getRGB){
img.setRGB(i,j,c.getRGB)
}
}
}
please i need help
I am trying to convert image .dcm to grayscale in java but i couldn't.
i wan't to know how to read image.dcm in java and convert it to grayscale.
note :: this code is already run for image .jpg,.png
package otsuthresholding;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;
public class OtsuThresholding {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
try {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME );
File input = new File("p.dcm");
BufferedImage image = ImageIO.read(input);
byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_8UC3);
mat.put(0, 0, data);
Mat mat1 = new Mat(image.getHeight(),image.getWidth(),CvType.CV_8UC1);
Imgproc.cvtColor(mat, mat1, Imgproc.COLOR_RGB2GRAY);
byte[] data1 = new byte[mat1.rows() * mat1.cols() * (int)(mat1.elemSize())];
mat1.get(0, 0, data1);
BufferedImage image1 = new BufferedImage(mat1.cols(),mat1.rows(), BufferedImage.TYPE_BYTE_GRAY);
image1.getRaster().setDataElements(0, 0, mat1.cols(), mat1.rows(), data1);
File ouptut = new File("grayscale.dcm");
ImageIO.write(image1, "dcm", ouptut);
} catch (IOException e) {
System.out.println("Error: " + e.getMessage());
}
}
}
I got the video stream from cctv camera using opencv. Now I want to detect a simple motion / object from this video stream. For example, if any person come in any selected zone then rectangular border should be generated around him. I search some opencv tutorial, but I didn't got any proper solution or idea.I used the following code to display video stream.
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
public class VideoStream
{
static BufferedImage tmpImg=null;
public static void main(String args[]) throws InterruptedException
{
System.out.println("opencv start..");
// Load native library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
VideoCapture camView=new VideoCapture();
camView.open("http://192.168.1.7:80/cgi-bin/view.cgi?chn=6&u=admin&p=");
if(!camView.isOpened())
{
System.out.println("Camera Error..");
}
else
{
System.out.println("Camera successfully opened");
}
videoCamera cam=new videoCamera(camView);
//Initialize swing components
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(cam);
frame.setSize(1024,768);
frame.setVisible(true);
while(camView.isOpened())
{
cam.repaint();
}
}
}
#SuppressWarnings("serial")
class videoCamera extends JPanel
{
VideoCapture camera;
Mat mat=new Mat();
public videoCamera(VideoCapture cam)
{
camera = cam;
}
public BufferedImage Mat2BufferedImage(Mat m)
{
int type = BufferedImage.TYPE_BYTE_GRAY;
if (m.channels() > 1)
{
type = BufferedImage.TYPE_3BYTE_BGR;
}
int bufferSize = m.channels() * m.cols() * m.rows();
byte[] b = new byte[bufferSize];
m.get(0, 0, b); // get all the pixels
BufferedImage img = new BufferedImage(m.cols(), m.rows(), type);
final byte[] targetPixels = ((DataBufferByte) img.getRaster().getDataBuffer()).getData();
System.arraycopy(b, 0, targetPixels, 0, b.length);
return img;
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Mat mat = new Mat();
camera.read(mat);
BufferedImage image = Mat2BufferedImage(mat);
g.drawImage(image,0,0,image.getWidth(),image.getHeight(), null);
}
}
Can any one knows how could we do that.
please check this code, but i implement it by python
import cv2, time, pandas
from datetime import datetime
first_frame = None
status_list = [None,None]
times = []
df=pandas.DataFrame(columns=["Start","End"])
video = cv2.VideoCapture('rtsp://admin:Paxton10#10.199.27.128:554')
while True:
check, frame = video.read()
status = 0
gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
gray = cv2.GaussianBlur(gray,(21,21),0)
if first_frame is None:
first_frame=gray
continue
delta_frame=cv2.absdiff(first_frame,gray)
thresh_frame=cv2.threshold(delta_frame, 30, 255, cv2.THRESH_BINARY)[1]
thresh_frame=cv2.dilate(thresh_frame, None, iterations=2)
(cnts,_)=cv2.findContours(thresh_frame.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
for contour in cnts:
if cv2.contourArea(contour) < 200000:
continue
status=1
(x, y, w, h)=cv2.boundingRect(contour)
cv2.rectangle(frame, (x, y), (x+w, y+h), (0,255,0), 3)
status_list.append(status)
status_list=status_list[-2:]
if status_list[-1]==1 and status_list[-2]==0:
times.append(datetime.now())
if status_list[-1]==0 and status_list[-2]==1:
times.append(datetime.now())
#cv2.imshow("Gray Frame",gray)
#cv2.imshow("Delta Frame",delta_frame)
imS = cv2.resize(thresh_frame, (640, 480))
cv2.imshow("Threshold Frame",imS)
imS = cv2.resize(frame, (640, 480))
cv2.imshow("Color Frame",imS)
#cv2.imshow("Color Frame",frame)
key=cv2.waitKey(1)
if key == ord('q'):
if status == 1:
times.append(datetime.now())
break
print(status_list)
print(times)
for i in range(0, len(times), 2):
df = df.append({"Start": times[i],"End": times[i+1]}, ignore_index=True)
df.to_csv("Times.csv")
video.release()
cv2.destroyAllWindows
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I'm looking for a free lib to convert from MS Word, WordPerfect and PDF to image.
Is anyone aware of any good, and up-to date JAVA library?
To convert PDF to images You can use PDFbox
Following is the code to convert PDF to images using pdfbox api
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageNode;
public List<String> generateImages(String pdfFile) throws IOException {
String imagePath = "/Users/$user/pdfimages/";
List <String> fileNames = new ArrayList<String>();
document = PDDocument.load(pdfFile); //// load pdf
node = document.getDocumentCatalog().getPages(); ///// get pages
List<PDPage> kids = node.getKids();
int count=0;
for(PDPage page : kids) { ///// iterate
BufferedImage img = page.convertToImage(BufferedImage.TYPE_INT_RGB,128);
File imageFile = new File(imagePath+ count++ + ".jpg");
ImageIO.write(img, "jpg", imageFile);
fileNames.add(imageFile.getName());
}
return fileNames;
}
Also another library ApachePOI can be used to convert PDF to Images
Here is the code sample
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.hslf.model.Slide;
import org.apache.poi.hslf.usermodel.SlideShow;
public class JavaApplication12 {
public static void main(String[] args) throws FileNotFoundException, IOException {
FileInputStream is = new FileInputStream(“D:/Presentation1.ppt”);
SlideShow ppt = new SlideShow(is);
is.close();
Dimension pgsize = ppt.getPageSize();
Slide[] slide = ppt.getSlides();
for (int i = 0; i < slide.length; i++) {
BufferedImage img = new BufferedImage(pgsize.width, pgsize.height, 1);
Graphics2D graphics = img.createGraphics();
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
graphics.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
graphics.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS,
RenderingHints.VALUE_FRACTIONALMETRICS_ON);
graphics.setColor(Color.white);
graphics.clearRect(0, 0, pgsize.width, pgsize.height);
graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));
// render
slide[i].draw(graphics);
// save the output
FileOutputStream out = new FileOutputStream(“slide-” + (i + 1) + “.png”);
javax.imageio.ImageIO.write(img, “png”, out);
out.close();
}
}
}
To convert MS Word to images you can have look at question posted here
Which uses JODConverter
JODConverter automates all conversions supported by OpenOffice.org, including
Any format to PDF
o OpenDocument (Text, Spreadsheet, Presentation) to PDF
o Word to PDF; Excel to PDF; PowerPoint to PDF
o RTF to PDF; WordPerfect to PDF; ...
And more
o OpenDocument Presentation (odp) to Flash; PowerPoint to Flash
o RTF to OpenDocument; WordPerfect to OpenDocument
o Any format to HTML (with limitations)
o Support for OpenOffice.org 1.0 and old StarOffice formats
//DOC to .jpeg
package org.doc;
import java.io.File;
import com.aspose.words.Document;
import com.aspose.words.ImageSaveOptions;
import com.aspose.words.SaveFormat;
public class DocToImage {
public static void main(String[] args) {
try {
String sourcePath = "D://G.doc";
Document doc = new Document(sourcePath);
ImageSaveOptions options = new ImageSaveOptions(SaveFormat.JPEG);
options.setJpegQuality(100);
options.setResolution(100);
options.setUseHighQualityRendering(true);
for (int i = 0; i < doc.getPageCount(); i++) {
String imageFilePath = "E://"+ "images" + File.separator + "img_" + i + ".jpeg";
options.setPageIndex(i);
doc.save(imageFilePath, options);
}
System.out.println("Done...");
} catch (Exception e) {
e.printStackTrace();
}
}
}
/*Here is the link from where we can download latest Aspose word jar.
http://www.aspose.com/java/word-component.aspx*/
//PDF to .png
package org.pdf;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.HeadlessException;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;
public class PdfToImage {
public static void main(final String[] args) throws Exception {
String storagePath = "E://dd.pdf";
//Image Save Directory
String realPathtopdfImageSaveDir = "E://uploads/";
RandomAccessFile raf = new RandomAccessFile(storagePath, "r");
FileChannel channel = raf.getChannel();
ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
PDFFile pdffile = new PDFFile(buf);
int numPgs = pdffile.getNumPages();
for (int i = 0; i < numPgs; i++) {
PDFPage page = pdffile.getPage(i);
Rectangle rect = new Rectangle(0, 0, (int) page.getBBox().getWidth(), (int) page.getBBox().getHeight());
Image img = page.getImage(rect.width, rect.height, rect, null, true, true);
// save it as a file
BufferedImage bImg = toBufferedImage(img);
File yourImageFile = new File(realPathtopdfImageSaveDir +File.separator + "page_" + i + ".png");
ImageIO.write(bImg, "png", yourImageFile);
}
}
public static BufferedImage toBufferedImage(Image image) {
if (image instanceof BufferedImage) {
return (BufferedImage) image;
}
image = new ImageIcon(image).getImage();
BufferedImage bimage = null;
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
try {
int transparency = Transparency.OPAQUE;
GraphicsDevice gs = ge.getDefaultScreenDevice();
GraphicsConfiguration gc = gs.getDefaultConfiguration();
bimage = gc.createCompatibleImage(image.getWidth(null), image.getHeight(null), transparency);
} catch (HeadlessException e) {
System.out.println("The system does not have a screen");
}
if (bimage == null) {
int type = BufferedImage.TYPE_INT_RGB;
bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
}
Graphics g = bimage.createGraphics();
g.drawImage(image, 0, 0, null);
g.dispose();
return bimage;
}
}
// jar required pdf-renderer.jar
I am working on a project related to colored image manipulation using JAVA.
I got to know the conversion of the colored image into a matrix using a getSample method of Raster class,
pixels[x][y]=raster.getSample(x,y,0);
I got the matrix in pixels[][] (only the values in red band).
Then i converted the matrix back to image using WritableRaster as,
raster.setSample(i,j,0,pixels[i][j]);
I converted it to image using,
*BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
image.setData(raster);*
But the problem is,
1) I want the colored image to be displayed as it is whereas i am getting only a particular band(like only red, only blue . . ) because I have to specify a band as per the prototype of the method setSample and getenter code hereSample.
2) How can i get a 2d matrix representing a colored image(of all 3 bands represented in 3 different matrices)
Here is the code that i wrote with the help of snippets of code online...
import java.awt.Image;
import java.awt.Point;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.SampleModel;
import java.awt.image.WritableRaster;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
class TestImage {
ImageIcon icon;
SampleModel sampleModel;
public static void main(String args[]){
TestImage mamu = new TestImage();
File file = new File("photo.jpg");
mamu.compute(file);
}
public void compute(File file){
try{
BufferedImage img= ImageIO.read(file);
Raster raster=img.getData();
sampleModel = raster.getSampleModel();
int w=raster.getWidth(),h=raster.getHeight();
int pixels[][]=new int[w][h];
for (int x=0;x<w;x++){
for(int y=0;y<h;y++){
pixels[x][y]=raster.getSample(x,y,0);
}
}
Image image = getImage(pixels);
JFrame frame = new JFrame("uff");
ImageIcon icon = new ImageIcon(image);
JLabel label = new JLabel(icon);
frame.setContentPane(label);
frame.setVisible(true);
frame.setSize(200,200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}catch (Exception e){
e.printStackTrace();
}
}
public java.awt.Image getImage(int pixels[][]){
int w=pixels.length;
int h=pixels[0].length;
WritableRaster raster= Raster.createWritableRaster(sampleModel, new Point(0,0));
for(int i=0;i<w;i++){
for(int j=0;j<h;j++){
raster.setSample(i,j,0,pixels[i][j]);
}
}
BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
image.setData(raster);
File output=new File("check.jpg");
try {
ImageIO.write(image,"jpg",output);
}catch (Exception e){
e.printStackTrace();
}
return image;
}
}
You may be looking or java.awt.image.LookupOp, which uses a java.awt.image.LookupTable to modify bands en bloc. Several examples are cited here. The image below illustrates inversion:
short[] invert = new short[256];
for (int i = 0; i < 256; i++) {
invert[i] = (short) (255 - i);
}
BufferedImageOp invertOp = new LookupOp(new ShortLookupTable(0, invert), null));
invertOp.filter(src, dst);