I am trying to convert RGB values of an image and get the HSV values of it. I am trying to do this without using Color.RGBtoHSB because I don't like the float values I want the numbers to be in the range of 0-255. When I run this program my conversion algorithm prints out nothing even though I ask it to print out values.
public void splitChannels() {
Mat firstImage = Imgcodecs.imread("darkGreen.jpg");
Imgproc.cvtColor(firstImage, firstImage, Imgproc.COLOR_BGR2RGB);
int width = 20;
int height = 20;
Rect roi = new Rect(100,100, width, height);
Mat smallImg = new Mat(firstImage, roi);
Imgproc.cvtColor(smallImg,smallImg,Imgproc.COLOR_BGR2RGB);
// 3 channels in smallImg
int channels = smallImg.channels();
int totalBytes = (int)(smallImg.total() * smallImg.channels());
byte buff[] = new byte[totalBytes];
smallImg.get(0, 0, buff);
for (int i=0; i< height; i++) {
// stride is the number of bytes in a row of smallImg
int stride = channels * width;
for (int j=0; j<stride; j+=channels) {
int r = buff[(i * stride) + j];
int g = buff[(i * stride) + j + 1];
int b = buff[(i * stride) + j + 2];
RGBtoHSV(r, g, b);
}
}
}
private int[] RGBtoHSV(int r, int g, int b){
int computedH = 0;
int computedS = 0;
int computedV = 0;
int[] HSVarr = new int[3];
HSVarr[0] = computedH;
HSVarr[1] = computedS;
HSVarr[2] = computedV;
if(r< 0 || g< 0 || b< 0 || r> 255 || g>255 || b> 255){
System.err.println("RGB values must be in range 0 to 255");
}
r=r/255; g=g/255; b=b/255;
int minRGB = Math.min(r, Math.min(g, b));
int maxRGB = Math.max(r, Math.min(g, b));
// Black-gray-white
if(minRGB==maxRGB){
computedV = minRGB;
return HSVarr;
}
int d = (r==minRGB) ? g-b : ((b==minRGB) ? r-g : b-r);
int h = (r==minRGB) ? 3 : ((b==minRGB) ? 1 : 5);
computedH = 60*(h - d/(maxRGB - minRGB));
computedS = (maxRGB = minRGB)/maxRGB;
computedV = maxRGB;
System.out.println("H: " + computedH + " V: "+ computedS +" S: " + computedV);
return HSVarr;
}
I am trying to convert RGB values of an image and get the HSV values of it. I am trying to do this without using Color.RGBtoHSB because I don't like the float values.
Create a wrapper method for the Color.RGBtoHSB(...) method to convert the float values to the appropriate int values.
Something like:
import java.awt.*;
public class Main
{
public static void main(String[] args) throws Exception
{
int[] hsb = RGBtoHSB(0, 0, 255);
for (int value: hsb)
System.out.println( value );
}
public static int[] RGBtoHSB(int red, int green, int blue)
{
float[] hsbFloat = Color.RGBtoHSB(red, green, blue, null);
int[] hsbInt = new int[3];
hsbInt[0] = Math.round( hsbFloat[0] * 360 );
hsbInt[1] = Math.round( hsbFloat[1] * 100 );
hsbInt[2] = Math.round( hsbFloat[2] * 100 );
return hsbInt;
}
}
Related
I wrote a code for processing and had formerly sorted pixels with selection sort. I have to hand it in and the teacher said it is taking to long like this, so I decided to divide the pixels brightness into parts of 50 and just sort it very roughly. The image that comes out isn't completely sorted though and I really don't know where it went wrong.
I doesn't have to be sorted perfectly - it's really just about having a cool-looking image as a result.
I hope some can help me and it is understandable what I mean!
Thanks in advance
PImage img;
PImage two;
PImage sorted;
int j = 0;
int x = j;
int y = x;
int u = y;
int h = u;
int d = 1;
void setup() {
size(736,1051);
img = loadImage("guy.png");
two = loadImage("guy2.png");
background(two);
}
void draw() {
loadPixels();
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int loc = x + y*width;
float r = red(img.pixels[loc]);
float g = green(img.pixels[loc]);
float b = blue(img.pixels[loc]);
float av = ((r+g+b)/3.0);
pixels[loc] = color(g,b,r, 17); //I know r, g, b are switched here
}
}
updatePixels();
save("guy_coloured.png");
}
void keyPressed(){
sorted = loadImage("guy_coloured.png");
sorted.loadPixels();
image(sorted, 0, 0);
System.out.print("doing it");
for (int i = 0; i < sorted.pixels.length; i++){
color colours = sorted.pixels[i];
float b = brightness(colours);
if(b<50){
sorted.pixels[j] = sorted.pixels[i];
j++;}
}
for (int f = 0; f < img.pixels.length; f++){
color colours = sorted.pixels[f];
float b = brightness(colours);
if(b<100 && b>50){
sorted.pixels[x] = sorted.pixels[f];
x++;}
}
for (int k = 0; k < img.pixels.length; k++){
color colours = sorted.pixels[k];
float b = brightness(colours);
if(b<150 && b>100){
sorted.pixels[y] = sorted.pixels[k];
y++;}
}
for (int t = 0; t < img.pixels.length; t++){
color colours = sorted.pixels[t];
float b = brightness(colours);
if(b<200 && b>150){
sorted.pixels[u] = sorted.pixels[t];
u++;}
}
for (int o = 0; o < img.pixels.length; o++){
color colours = sorted.pixels[o];
float b = brightness(colours);
if(b>200){
sorted.pixels[h] = sorted.pixels[o];
h++;}
}
System.out.print("done");
sorted.updatePixels();
image(sorted, 0, 0);
save("guy_sorted.png");
noLoop();
}
I want the whole image to be sorted, but it gives me back the normal image with about 1/4 sorted from the top.
This is the current result:
https://imgur.com/kHffIpm
Full code including irrelevant parts: https://docs.google.com/document/d/1YC97YMq9fKcbCAn3_RvLIm1bNo72FrNnHT3obc9pp7U/edit?usp=sharing
You do not sort the pixels. What you actually do is to arrange the dark pixel at the begin of the image and overwrite the pixels which are there. If you want to sort the pixels, then you've to swap them.
Write a function which can swap 2 pixel:
void Swap(PImage toSort, int i1, int i2) {
color c = toSort.pixels[i1];
toSort.pixels[i1] = toSort.pixels[i2];
toSort.pixels[i2] = c;
}
Once some pixels have been sorted, and are arranged at the begin of the image, this area doesn't need to be investigated further.
Write a function which sorts pixels dependent on a brightness range [b_min, b_max] and start at a certain index start:
int Sort(PImage toSort, int start, float b_min, float b_max) {
for (int i = start; i < toSort.pixels.length; i++) {
float b = brightness(toSort.pixels[i]);
if (b >= b_min && b < b_max) {
Swap(toSort, i, start);
start ++;
}
}
return start;
}
Sort the image by ascending brightness. e.g:
PImage img, two, sorted;
void setup() {
size(736,1051);
img = loadImage("guy.png");
two = loadImage("guy2.png");
background(two);
}
void draw() {
loadPixels();
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int loc = x + y*width;
float r = red(img.pixels[loc]), g = green(img.pixels[loc]), b = blue(img.pixels[loc]);
pixels[loc] = color(g,b,r, 17); //I know r, g, b are switched here
}
}
updatePixels();
save("guy_coloured.png");
}
void Swap(PImage toSort, int i1, int i2) {
color c = toSort.pixels[i1];
toSort.pixels[i1] = toSort.pixels[i2];
toSort.pixels[i2] = c;
}
int Sort(PImage toSort, int start, float b_min, float b_max) {
for (int i = start; i < toSort.pixels.length; i++) {
float b = brightness(toSort.pixels[i]);
if (b >= b_min && b < b_max) {
Swap(toSort, i, start);
start ++;
}
}
return start;
}
void keyPressed(){
sorted = loadImage("guy_coloured.png");
sorted.loadPixels();
image(sorted, 0, 0);
System.out.print("doing it");
int j = 0;
j = Sort(sorted, j, 0.0, 50.0);
j = Sort(sorted, j, 0.50, 100.0);
j = Sort(sorted, j, 0.100, 150.0);
j = Sort(sorted, j, 0.150, 200.0);
j = Sort(sorted, j, 0.200, 256.0);
System.out.print("done");
sorted.updatePixels();
image(sorted, 0, 0);
save("guy_sorted.png");
noLoop();
}
So I am trying to write a program that uses sobel operator to detect edges in an image. Below is my method.
/**
* Detects edges.
* #param url - filepath to the iamge.
*/
private void detect(String url) {
BufferedImage orgImage = readImage(url);
int width = orgImage.getWidth();
int height = orgImage.getHeight();
BufferedImage resImage = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY);
WritableRaster inraster = orgImage.getRaster();
WritableRaster outraster = resImage.getRaster();
System.out.println("size: " + width + "X" + height);
// Loop through every pixel, ignores the edges as these will throw out of
//bounds.
for (int i = 1; i < width-2; i++) {
for (int j = 1; j < height-2; j++) {
// Compute filter result, loops over in a
// box pattern.
int sum = 0;
for (int x = -1; x <= 1; x++) {
for (int y = -1; y <= 1; y++) {
int sum1 = i+y;
int sum2 = j+x;
int p = inraster.getSample(sum1, sum2, 0);
sum = sum + p;
}
}
int q = (int) Math.round(sum / 9.0);
if(q<150){
q = 0;
}else{
q = 255;
}
outraster.setSample(i, j, 0, q);
}
}
writeImage(resImage, "jpg", "EdgeDetection " + url);
}
This mostly just gives me a black and white image:
Before
After
I am obviosly calculating the pixel value wrong somehow. I am also note sure what value to use when deciding if the pixel should be black or white.
I'm a beginner to Java programming. I have the algorithm but I'm having trouble to code it. I would like to compare 2 similar images at position 2 and 4 of RGB hexadecimal pixel values to check whether one of the images has different pixel values than the other one.
My Algorithm logic:
if(image1.substring2 == image2.substring2) && (image1.substring4 == image2.substring4), pixels are the same.
if(image1.substring2 != image2.substring2) || (image1.substring4 != image2.substring4), pixels are not the same.
if(image1.substring2 != image2.substring2) && (image1.substring4 != image2.substring4), pixels are not the same.
I have the remaining codes here. I tried to separate all the process so it is easy for me to troubleshoot later.
//MAIN
public class getPixelRGB1
{
private static int a;
private static int r;
private static int g;
private static int b;
private static final double bitPerColor = 4.0;
public static void main(String[] args) throws IOException
{
FileInputStream image = null;
FileInputStream image2 = null;
getPixelData1 newPD = new getPixelData1();
try {
BufferedImage img, img2;
File file = new File("img0.jpg");
File file2 = new File("imgstega.jpg");
image = new FileInputStream(file);
image2 = new FileInputStream(file2);
img = ImageIO.read(image);
img2 = ImageIO.read(image2);
int rowcol;
int width = img.getWidth();
int height = img.getHeight();
System.out.println("Image's Width: " + width);
System.out.println("Image's Height: " + height);
int[][] pixelData = new int[width * height][3];
System.out.println("Pixel Data: " + pixelData);
int[] rgb;
int count = 0;
for(int i=0; i<width; i++)
{
for(int j=0; j<height; j++)
{
rgb = newPD.getPixelData(img, i, j);
for(int k = 0; k < rgb.length; k++)
{
pixelData[count][k] = rgb[k];
}
count++;
System.out.println("\nRGB Counts: " + count);
}
}
int width2 = img2.getWidth();
int height2 = img2.getHeight();
System.out.println("Image's Width: " + width2);
System.out.println("Image's Height: " + height2);
int[][] pixelData2 = new int[width2 * height2][3];
int[] rgb2;
int counter = 0;
for(int i=0; i<width2; i++)
{
for(int j=0; j<height2; j++)
{
rgb2 = newPD.getPixelData(img2, i, j);
for(int k = 0; k < rgb2.length; k++)
{
pixelData2[counter][k] = rgb2[k];
}
counter++;
System.out.println("\nRGB2 Counts: " + counter);
}
}
} catch (FileNotFoundException ex) {
Logger.getLogger(getPixelRGB1.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
image.close();
} catch (IOException ex) {
Logger.getLogger(getPixelRGB1.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
//1ST PROCESS - Get RGB Pixel Values
public class getPixelData1
{
private static final double bitPerColor = 4.0;
public int[] getPixelData(BufferedImage img, int w, int h) throws IOException
{
int argb = img.getRGB(w, h);
int rgb[] = new int[]
{
(argb >> 16) & 0xff, //red
(argb >> 8) & 0xff, //green
(argb ) & 0xff //blue
};
int red = rgb[0];
int green = rgb[1]; //RGB Value in Decimal
int blue = rgb[2];
System.out.println("\nRGBValue in Decimal --> " + "\nRed: " + red + " Green: " + green + " Blue: " + blue);
//Convert each channel RGB to Hexadecimal value
String rHex = Integer.toHexString((int)(red));
String gHex = Integer.toHexString((int)(green));
String bHex = Integer.toHexString((int)(blue));
System.out.println("\nRGBValue in Hexa --> " + "\nRed Green Blue " + rHex + gHex + bHex);
//Check position 2 and 4 of hexa value for any changes
String hexa2, hexa4 = "";
String rgbHexa = rHex + gHex + bHex;
hexa2 = rgbHexa.substring(1,2);
System.out.println("\nString RGB Hexa: " + rgbHexa);
System.out.println("\nSubstring at position 2: " + hexa2);
String hex = String.format("%02X%02X%02X", red, green, blue);
hexa4 = hex.substring(3,4);
System.out.println("\nSubstring at position 4: " + hexa4);
return rgb;
}
}
//2nd Process - to compare the RGB Hex value of both images
public class compareHexaRGB
{
public int[] compareHexaRGB(BufferedImage img, BufferedImage img2, int w, int h) throws IOException
{
getPixelData1 newPD = new getPixelData1(); //get method from class getPixelData1 - is this correct?
if((img.hexa2.equals(img2.hexa2)) && (img.hexa4.equals(img2.hexa4)))
{
System.out.println("Pixel values at position 2 and 4 are the same.");
}
else if((img.hexa2 != img2.hexa2) || (img.hexa4 != img2.hexa4))
{
System.out.println("Pixel values at position 2 and 4 are not the same.");
}
else if((img.hexa2 != img2.hexa2) && (img.hexa4 != img2.hexa4))
{
System.out.println("Pixel values at position 2 and 4 are not the same.");
}
}
}
The error stated that the program cannot find symbol for hexa2 and hexa4 in bufferedImage. Can someone check whether I've done something wrong with my coding here? I'm still new to Java.
img is of type BufferedImage (javadoc). It does not contain any non-private (nor private) fields named hexa2 or hexa4.
What you need to do is to refactor your code to make sure you have access to them in compareHexaRGB(). There are probably many ways this can be done. Perhaps you could extend BufferedImage to include your fields, or perhaps you could just pass them as input to the method.
Which solution that would be the more elegant one is hard to determine given that we don't really have all your code (for example, I don't see compareHexaRGB() being called at all).
To be more precise about the compilation problem: By using img.hexa2 to access a field, you assume that there is a field called hexa2 in BufferedImage that is accessible from your class. This is true if a field for example is declared as public. More typically, the fields are private scoped and need to be accessed by a getter/setter. For BufferedImage, no such field exists at all.
Learn about access control here.
I am trying to find the color that most suits a loaded image and apply it in the background. To adapt to the image and make the UI feel more natural.
i have so far found 2 schemes :
1> averaging the pixels(Code Below) :
final Color acclimatizeAverage(BufferedImage img) {
long avgr = 0, avgb = 0, avgg = 0;
for (int i = 0; i < img.getWidth(); i++) {
for (int j = 0; j < img.getHeight(); j++) {
Color c = new Color(img.getRGB(i, j));
avgr += c.getRed(); avgb += c.getBlue(); avgg += c.getGreen();
}
}
avgr = (avgr/(img.getHeight()*img.getWidth()));
avgg = (avgg/(img.getHeight()*img.getWidth()));
avgb = (avgb/(img.getHeight()*img.getWidth()));
Color c = new Color((int)avgr, (int)avgg, (int)avgb);
return c;
}
2> Grouping the pixels into fixed bins of Colors(Code Below) :
Map<Color, Integer> createBins() {
Map<Color, Integer> bins = new HashMap<>();
bins.put(Color.red, 0);
bins.put(Color.magenta, 0);
bins.put(Color.orange, 0);
bins.put(Color.PINK, 0);
bins.put(Color.yellow, 0);
bins.put(Color.LIGHT_GRAY, 0);
bins.put(Color.GREEN, 0);
bins.put(Color.GRAY, 0);
bins.put(Color.DARK_GRAY, 0);
bins.put(Color.CYAN, 0);
bins.put(Color.BLUE, 0);
bins.put(Color.BLACK, 0);
return bins;
}
int compare(Color a, Color b) {
return (int)Math.sqrt((a.getRed() - b.getRed())*(a.getRed() - b.getRed())
+ (a.getBlue() - b.getBlue())*(a.getBlue() - b.getBlue())
+ (a.getGreen()- b.getGreen())*(a.getGreen()- b.getGreen()));
}
BufferedImage acclimatizeGrouping(BufferedImage img) {
Map<Color, Integer> bins = createBins();
for (int i = 0; i < img.getWidth(); i++) {
int min = Integer.MAX_VALUE; Color minC = null;
for (int j = 0; j < img.getHeight(); j++) {
Color c = new Color(img.getRGB(i, j));
for (Map.Entry<Color, Integer> entry : bins.entrySet()) {
Integer integer = compare(entry.getKey(), c);
if(integer < min) {
min = integer;
minC = entry.getKey();
}
}
bins.put(minC, bins.get(minC)+1);
}
}
int max = -1, n = 1; Color c = null;
for (Map.Entry<Color, Integer> entry : bins.entrySet()) {
Integer integer = entry.getValue();
if(integer > max) {
max = integer;
c = entry.getKey();
}
}
return c;
}
But the grouping is producing weird results....
left side is the Color produced as a result of grouping and right side is image
Why is it producing such results ???
averaing is producing more correct results :
I think the problem is that RGB is not human euclidean space. You use euclidean distance to compare colors, but it is not good for human color sense. See this link for more information.
EDIT: More precise, you should use this algorithm:
typedef struct {
unsigned char r, g, b;
} RGB;
double ColourDistance(RGB e1, RGB e2)
{
long rmean = ( (long)e1.r + (long)e2.r ) / 2;
long r = (long)e1.r - (long)e2.r;
long g = (long)e1.g - (long)e2.g;
long b = (long)e1.b - (long)e2.b;
return sqrt((((512+rmean)*r*r)>>8) + 4*g*g + (((767-rmean)*b*b)>>8));
}
This issue is, your compare(Color a, Color b) method is not implemented correctly and can use some basic refactoring using the Math.pow() method.
The basic formula to find similar colors programatically is
((r2 - r1)2 + (g2 - g1)2 + (b2 - b1)2)1/2
Applied to Java, that results in the modified compare(Color a, Color b)
int compare(Color a, Color b){
return Math.sqrt(( Math.pow( b.getRed() - a.getRed() )
+ ( Math.pow( b.getGreen() - a.getGreen() )
+ ( Math.pow( b.getBlue() - a.getBlue() ));
}
public static void sample(BufferedImage image) {
int width = image.getWidth();
int height = image.getHeight();
int value[][] = new int[width][height];
int valueR[][] = new int[width][height];
int valueG[][] = new int[width][height];
int valueB[][] = new int[width][height];
for (int j = 0; j < height; j++) {
for (int i = 0; i < width; i++) {
int pixel = image.getRGB(i, j);
value[i][j] = pixel;
Color c = new Color(pixel);
valueR[i][j]= c.getRed();
valueG[i][j] = c.getGreen();
valueB[i][j] = c.getBlue();
System.out.println("Red value = "+valueR[i][j]);
System.out.println("Green value ="+valueG[i][j]);
System.out.println("Blue value"+valueB[i][j]);
}
}
}
The above code is to store RGB values and pixel color values of an image in an array separately.
public static BigInteger modPow(BigInteger a1, BigInteger e, BigInteger n) {
BigInteger r = 1;
for (int i = e.bitLength() - 1; i >= 0; i--) {
r = (r.multiply(r)).mod(n);
if (e.testBit(i)) {
r = (r.multiply(a1)).mod(n);
}
}
System.out.println("C value = " + r);
int lng = 3;
BigInteger bi = BigInteger.valueOf(lng);
BigInteger a = r.divide(bi);
BigInteger b = r.mod(bi);
System.out.println("pixel position a = " + a);
System.out.println("modulus value b = " + b);
return r;
}
In the above code am finding pixel position where i need to embed the secret bit.so i need to go to that specific pixel to embed the message.But in the previous code am storing pixel color in array value[][].i need to search through the array value[][] to get the pixel position which i got in last code.
Note: a1 is the position of current bit of information file to embed
{e,n} is public key
My question is how to find the pixel positions?
To find the position of a pixel is a simple concept with a complex execution. I've written some code here that takes a BufferedImage and searches through it for a pixel of a specific color.
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import java.io.IOException;
public class pixelSearch {
public static void main(String[] args) {
//I don't know where you're getting your image but i'll get one from file
File image = new File("image.bmp");
try {
BufferedImage imageToSearch = ImageIO.read(image);
Color colorToFind = new Color(255,255,255); //define color to search for with RGB vals 255,255,255
//for more information on constructing colors look here: http://docs.oracle.com/javase/7/docs/api/java/awt/Color.html
int[] pixelCoordinates = pSearch( colorToFind, imageToSearch ); //search for the pixel
System.out.println("Found pixel at (" + pixelCoordinates[0] + "," + pixelCoordinates[1] + ")."); //display coordinates
} catch (IOException e) {
System.out.println(e.toString());
}
}
private static int[] pSearch ( Color c, BufferedImage pic ){
int cVal = c.getRGB(); //get integer value of color we are trying to find
int x1 = 0;
int y1 = 0;
int x2 = pic.getWidth();
int y2 = pic.getHeight();
int[] XArray = new int[x2-x1+1]; //create an array to hold all X coordinates in image
int iterator = 0;
while (iterator <= x2) {
XArray[iterator] = x1 + iterator;
iterator++;
}
int [] YArray = new int[y2-y1+1]; //create an array to hold all Y coordinates in image
iterator = 0;
while (iterator <= y2) {
YArray[iterator] = y1 + iterator;
iterator++;
}
//next we iterate throug all the possible coordinates to check each pixel
for (int yVal : YArray) {
for (int xVal : XArray) {
int color = pic.getRGB(xVal, yVal); //get the color of pixel at coords (xVal, yVal)
if (color == cVal) { //if the color is equal to the one we inputted to the function
int[] cPos = {xVal, yVal}; //store the coordinates
return cPos; //return the coordinates
}
}
}
int[] returnVal = {-1,-1}; //if we didn't find it return -1, -1
return returnVal;
}
}