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getRGB(x,y) in Java awt returns for each pixel same value

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-5

I tried to walk through an image and take each RGB color value from all pixels and process them. But I get for all pixels the same RGB value. So obviously that is wrong.

I used the getRGB(x,y) method of an bufferedimage object in Java awt.
Know anyone what's the problem here?

Edit:

I got the problem, there were some mistakes by converting the image to an buffered image. I didn't draw the image in the in the buffered image.
The Following code working now as intended.

 public void printImgDetails(Image img) 

 // get the sizes of the image
 long heigth = img.getHeight(null);
 long width = img.getWidth(null);

 // hashSet to hold all brightness values
 HashSet<Float> set = new HashSet<Float>(0);

 BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_BYTE_GRAY);
 int rgb;
 float[] hsv = new float[3];

 // Draw the image on to the buffered image
 Graphics2D bGr = bimage.createGraphics();
 bGr.drawImage(img, 0, 0, null);
 bGr.dispose();

 for (int i = 0; i < width; i++) 
 for (int j = 0; j < heigth; j++) 
 Color c = new Color(bimage.getRGB(j, i));

 int r = c.getRed();
 int g = c.getGreen();
 int b = c.getBlue();

 Color.RGBtoHSB(r, g, b, hsv);
 System.out.println("r: " + r + " g: " + g + " b: " + b);
 set.add(hsv[2]);
 
 

 // calculate the average brightness
 double sum = 0;
 for (float x : set) 
 sum += x;
 
 double avg = sum / set.size();

 // print the results
 System.out.println("avg --> " + avg);

Thanks in advance.

java image-processing awt rgb

share|improve this question

edited Mar 26 at 19:56

Sebastian T

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  
  A guess: the problem is somewhere in your code ... right there, see it? Seriously: how are we supposed to help if you don't even show any code? And did you step through your code with a debugger yet?
  
  – Thomas
  Mar 26 at 10:40
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  please read How to Ask
  
  – Piglet
  Mar 26 at 10:47
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  first thanks for your answer, here is the code and of corse Id step trough with a debugger. But now it is working
  
  – Sebastian T
  Mar 26 at 19:53
  

  
  
  
  

add a comment | 

-5

I tried to walk through an image and take each RGB color value from all pixels and process them. But I get for all pixels the same RGB value. So obviously that is wrong.

I used the getRGB(x,y) method of an bufferedimage object in Java awt.
Know anyone what's the problem here?

Edit:

I got the problem, there were some mistakes by converting the image to an buffered image. I didn't draw the image in the in the buffered image.
The Following code working now as intended.

 public void printImgDetails(Image img) 

 // get the sizes of the image
 long heigth = img.getHeight(null);
 long width = img.getWidth(null);

 // hashSet to hold all brightness values
 HashSet<Float> set = new HashSet<Float>(0);

 BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_BYTE_GRAY);
 int rgb;
 float[] hsv = new float[3];

 // Draw the image on to the buffered image
 Graphics2D bGr = bimage.createGraphics();
 bGr.drawImage(img, 0, 0, null);
 bGr.dispose();

 for (int i = 0; i < width; i++) 
 for (int j = 0; j < heigth; j++) 
 Color c = new Color(bimage.getRGB(j, i));

 int r = c.getRed();
 int g = c.getGreen();
 int b = c.getBlue();

 Color.RGBtoHSB(r, g, b, hsv);
 System.out.println("r: " + r + " g: " + g + " b: " + b);
 set.add(hsv[2]);
 
 

 // calculate the average brightness
 double sum = 0;
 for (float x : set) 
 sum += x;
 
 double avg = sum / set.size();

 // print the results
 System.out.println("avg --> " + avg);

Thanks in advance.

java image-processing awt rgb

share|improve this question

edited Mar 26 at 19:56

Sebastian T

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

• 
  
  
  

  
  5
  

  
  
  
  
  
  

  
  
  A guess: the problem is somewhere in your code ... right there, see it? Seriously: how are we supposed to help if you don't even show any code? And did you step through your code with a debugger yet?
  
  – Thomas
  Mar 26 at 10:40
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  please read How to Ask
  
  – Piglet
  Mar 26 at 10:47
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  first thanks for your answer, here is the code and of corse Id step trough with a debugger. But now it is working
  
  – Sebastian T
  Mar 26 at 19:53
  

  
  
  
  

add a comment | 

I tried to walk through an image and take each RGB color value from all pixels and process them. But I get for all pixels the same RGB value. So obviously that is wrong.

I used the getRGB(x,y) method of an bufferedimage object in Java awt.
Know anyone what's the problem here?

Edit:

I got the problem, there were some mistakes by converting the image to an buffered image. I didn't draw the image in the in the buffered image.
The Following code working now as intended.

 public void printImgDetails(Image img) 

 // get the sizes of the image
 long heigth = img.getHeight(null);
 long width = img.getWidth(null);

 // hashSet to hold all brightness values
 HashSet<Float> set = new HashSet<Float>(0);

 BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_BYTE_GRAY);
 int rgb;
 float[] hsv = new float[3];

 // Draw the image on to the buffered image
 Graphics2D bGr = bimage.createGraphics();
 bGr.drawImage(img, 0, 0, null);
 bGr.dispose();

 for (int i = 0; i < width; i++) 
 for (int j = 0; j < heigth; j++) 
 Color c = new Color(bimage.getRGB(j, i));

 int r = c.getRed();
 int g = c.getGreen();
 int b = c.getBlue();

 Color.RGBtoHSB(r, g, b, hsv);
 System.out.println("r: " + r + " g: " + g + " b: " + b);
 set.add(hsv[2]);
 
 

 // calculate the average brightness
 double sum = 0;
 for (float x : set) 
 sum += x;
 
 double avg = sum / set.size();

 // print the results
 System.out.println("avg --> " + avg);

Thanks in advance.

java image-processing awt rgb

share|improve this question

edited Mar 26 at 19:56

Sebastian T

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

 public void printImgDetails(Image img) 

 // get the sizes of the image
 long heigth = img.getHeight(null);
 long width = img.getWidth(null);

 // hashSet to hold all brightness values
 HashSet<Float> set = new HashSet<Float>(0);

 BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_BYTE_GRAY);
 int rgb;
 float[] hsv = new float[3];

 // Draw the image on to the buffered image
 Graphics2D bGr = bimage.createGraphics();
 bGr.drawImage(img, 0, 0, null);
 bGr.dispose();

 for (int i = 0; i < width; i++) 
 for (int j = 0; j < heigth; j++) 
 Color c = new Color(bimage.getRGB(j, i));

 int r = c.getRed();
 int g = c.getGreen();
 int b = c.getBlue();

 Color.RGBtoHSB(r, g, b, hsv);
 System.out.println("r: " + r + " g: " + g + " b: " + b);
 set.add(hsv[2]);
 
 

 // calculate the average brightness
 double sum = 0;
 for (float x : set) 
 sum += x;
 
 double avg = sum / set.size();

 // print the results
 System.out.println("avg --> " + avg);

share|improve this question

edited Mar 26 at 19:56

Sebastian T

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

share|improve this question

edited Mar 26 at 19:56

Sebastian T

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

asked Mar 26 at 10:38

Sebastian TSebastian T

2344 bronze badges

2 Answers
2

active

oldest

votes

0

If you get the same values for every pixel there are several possible reasons.

a) your image has the same values in every pixel

b) you do not change x and y between your calls to getRGB

c) you read something else but the return value of getRGB

share|improve this answer

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

add a comment | 

0

As I wirte in the edit, there was an problem by converting between image and bufferedimage. I forgot to draw image into the bufferediamge. Thats it.

share|improve this answer

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  consider deleting your question. I doubt it's of any use to anyone
  
  – Piglet
  Mar 26 at 22:10
  

  
  
  
  

add a comment | 

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0

If you get the same values for every pixel there are several possible reasons.

a) your image has the same values in every pixel

b) you do not change x and y between your calls to getRGB

c) you read something else but the return value of getRGB

share|improve this answer

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

add a comment | 

0

If you get the same values for every pixel there are several possible reasons.

a) your image has the same values in every pixel

b) you do not change x and y between your calls to getRGB

c) you read something else but the return value of getRGB

share|improve this answer

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

add a comment | 

If you get the same values for every pixel there are several possible reasons.

a) your image has the same values in every pixel

b) you do not change x and y between your calls to getRGB

c) you read something else but the return value of getRGB

share|improve this answer

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

share|improve this answer

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

answered Mar 26 at 10:45

PigletPiglet

9,09822 gold badges1111 silver badges2323 bronze badges

0

As I wirte in the edit, there was an problem by converting between image and bufferedimage. I forgot to draw image into the bufferediamge. Thats it.

share|improve this answer

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  consider deleting your question. I doubt it's of any use to anyone
  
  – Piglet
  Mar 26 at 22:10
  

  
  
  
  

add a comment | 

0

As I wirte in the edit, there was an problem by converting between image and bufferedimage. I forgot to draw image into the bufferediamge. Thats it.

share|improve this answer

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  consider deleting your question. I doubt it's of any use to anyone
  
  – Piglet
  Mar 26 at 22:10
  

  
  
  
  

add a comment | 

As I wirte in the edit, there was an problem by converting between image and bufferedimage. I forgot to draw image into the bufferediamge. Thats it.

share|improve this answer

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

share|improve this answer

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges

answered Mar 26 at 20:02

Sebastian TSebastian T

2344 bronze badges