これまで OpenCV を使用したことはありませんが、テキストを認識するニューラル ネットワーク システムを作成しようとしており、テキストの抽出/セグメンテーション用のツールが必要です。
Java OpenCV を使用して、テキストを含む画像を前処理してセグメント化するにはどうすればよいですか。
テキストを認識する必要はありません。各文字を個別の画像で取得する必要があるだけです。
このようなもの ：
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あなたがやろうとしているのは、一般的なシーンのテキストのローカリゼーションの問題であり、かなり困難です。インスピレーションについては、この記事をご覧ください - http://www.maseltov.eu/wp-content/uploads/2014/02/CTU-03_Real-Time-Scene-Text-Localization-and-Recognition.pdf
あなたができることは次のとおりです。
- 画像から MSER オブジェクトを抽出するプログラムを書く
- 個々の MSER によって決定されたすべてのパッチから機能を抽出します (どの機能が記事で概説されているか)
- 文字領域と非文字領域を区別できるように、分類子 (あなたの場合はニューラル ネットワークだと思いますか?) をトレーニングします。
- 分類器を使用して MSER を抽出し、トレーニング済みの NN を使用してそれらを分類するプログラムを作成します。
MSER アルゴリズムは OpenCV で実装されているため、これはプラスです。そこにはニューラルネットワーク分類器もありますが、私はSVMしか使っていないので、それについてはあまりコメントできません。この問題も解決する必要がありましたが、OpenCV を使用して解決することは完全に可能です。銀の大皿にすべてを載せることを期待しないでください。多くの作業が必要です。特にブロブの特徴を選択して抽出するとき。
于 2014-04-06T19:35:46.657 に答える
0
このコードを試してください。OpenCVは必要ありません
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import org.neuroph.imgrec.ImageUtilities;
public class CharExtractor {
private int cropTopY = 0;//up locked coordinate
private int cropBottomY = 0;//down locked coordinate
private int cropLeftX = 0;//left locked coordinate
private int cropRightX = 0;//right locked coordinate
private BufferedImage imageWithChars = null;
private boolean endOfImage;//end of picture
private boolean endOfRow;//end of current reading row
/**
* Creates new char extractor with soecified text image
* @param imageWithChars - image with text
*/
public CharExtractor(BufferedImage imageWithChars) {
this.imageWithChars = imageWithChars;
}
public void setImageWithChars(BufferedImage imageWithChars) {
this.imageWithChars = imageWithChars;
}
/**
* This method scans image pixels until it finds the first black pixel (TODO: use foreground color which is black by default).
* When it finds black pixel, it sets cropTopY and returns true. if it reaches end of image and does not find black pixels,
* it sets endOfImage flag and returns false.
* @return - returns true when black pixel is found and cropTopY value is changed, and false if cropTopY value is not changed
*/
private boolean findCropTopY() {
for (int y = cropBottomY; y < imageWithChars.getHeight(); y++) { // why cropYDown? - for multiple lines of text using cropBottomY from previous line above; for first line its zero
for (int x = cropLeftX; x < imageWithChars.getWidth(); x++) { // scan starting from the previous left crop position - or it shoud be right???
if (imageWithChars.getRGB(x, y) == -16777216) { // if its black rixel (also consider condition close to black or not white or different from background)
this.cropTopY = y; // save the current y coordiante
return true; // and return true
}
}
}
endOfImage = true; //sets this flag if no black pixels are found
return false; // and return false
}
/**
* This method scans image pixels until it finds first row with white pixels. (TODO: background color which is white by default).
* When it finds line whith all white pixels, it sets cropBottomY and returns true
* @return - returns true when cropBottomY value is set, false otherwise
*/
private boolean findCropBottomY() {
for (int y = cropTopY + 1; y < imageWithChars.getHeight(); y++) { // scan image from top to bottom
int whitePixCounter = 0; //counter of white pixels in a row
for (int x = cropLeftX; x < imageWithChars.getWidth(); x++) { // scan all pixels to right starting from left crop position
if (imageWithChars.getRGB(x, y) == -1) { // if its white pixel
whitePixCounter++; // increase counter
}
}
if (whitePixCounter == imageWithChars.getWidth()-1) { // if we have reached end of line counting white pixels (x pos)
cropBottomY = y;// that means that we've found white line, so set current y coordinate minus 1
return true; // as cropBottomY and finnish with true
}
if (y == imageWithChars.getHeight() - 1) { // if we have reached end of image
cropBottomY = y; // set crop bottom
endOfImage = true; // set corresponding endOfImage flag
return true; // and return true
}
}
return false; // this should never happen, however its possible if image has non white bg
}
private boolean findCropLeftX() {
int whitePixCounter = 0; // white pixel counter between the letters
for (int x = cropRightX; x < imageWithChars.getWidth(); x++) { // start from previous righ crop position (previous letter), and scan following pixels to the right
for (int y = cropTopY; y <= cropBottomY; y++) { // vertical pixel scan at current x coordinate
if (imageWithChars.getRGB(x, y) == -16777216) { // when we find black pixel
cropLeftX = x; // set cropLeftX
return true; // and return true
}
}
// BUG?: this condition looks strange.... we might not need whitePixCounter at all, it might be used for 'I' letter
whitePixCounter++; // if its not black pixel assume that its white pixel
if (whitePixCounter == 3) { // why 3 pixels? its hard coded for some case and does not work in general...!!!
whitePixCounter = 0; // why does it sets to zero, this has no purporse at all...
}
}
endOfRow = true; // if we have reached end of row and we have not found black pixels, set the endOfRow flag
return false; // and return false
}
/**
* This method scans image pixels to the right until it finds next row where all pixel are white, y1 and y2.
* @return - return true when x2 value is changed and false when x2 value is not changed
*/
private boolean findCropRightX() {
for (int x = cropLeftX + 1; x < imageWithChars.getWidth(); x++) { // start from current cropLeftX position and scan pixels to the right
int whitePixCounter = 0;
for (int y = cropTopY; y <= cropBottomY; y++) { // vertical pixel scan at current x coordinate
if (imageWithChars.getRGB(x, y) == -1) { // if we have white pixel at current (x, y)
whitePixCounter++; // increase whitePixCounter
}
}
// this is for space!
int heightPixels = cropBottomY - cropTopY; // calculate crop height
if (whitePixCounter == heightPixels+1) { // if white pixel count is equal to crop height+1 then this is white vertical line, means end of current char/ (+1 is for case when there is only 1 pixel; a 'W' bug fix)
cropRightX = x; // so set cropRightX
return true; // and return true
}
// why we need this when we allready have condiiton in the for loop? - for the last letter in the row.
if (x == imageWithChars.getWidth() - 1) { // if we have reached end of row with x position
cropRightX = x; // set cropRightX
endOfRow = true; // set endOfRow flag
return true; // and return true
}
}
}
public List<BufferedImage> extractCharImagesToRecognize() {
List<BufferedImage> trimedImages = new ArrayList<BufferedImage>();
int i = 0;
while (endOfImage == false) {
endOfRow = false;
boolean foundTop = findCropTopY();
boolean foundBottom = false;
if (foundTop == true) {
foundBottom = findCropBottomY();
if (foundBottom == true) {
while (endOfRow == false) {
boolean foundLeft = false;
boolean foundRight = false;
foundLeft = findCropLeftX();
if (foundLeft == true) {
foundRight = findCropRightX();
if (foundRight == true) {
BufferedImage image = ImageUtilities.trimImage(ImageUtilities.cropImage(imageWithChars, cropLeftX, cropTopY, cropRightX, cropBottomY));
trimedImages.add(image);
i++;
}
}
}
cropLeftX = 0;
cropRightX = 0;
}
}
}
cropTopY = 0;
cropBottomY = 0;
endOfImage = false;
return trimedImages;
}
public static void main(String[] args) throws Exception {
File f=new File("./written.png");
BufferedImage img=ImageIO.read(f);
CharExtractor ch=new CharExtractor(img);
List<BufferedImage> list=ch.extractCharImagesToRecognize();
for(int i=0;i<list.size();i++)
{
File outputfile = new File("./char_" +i+ ".png");
ImageIO.write(list.get(i),"png", outputfile);
}
}
}
于 2014-04-05T10:31:22.037 に答える