How do I separates text region from image in java

Question

I am working on OCR to recognised passport details, Since I am using Tesseract Java API. To achieve better accuracy I need to divide the whole image (can be of .png,.jpeg, .tiff) only into text regions. Is there any open source java library which separates text regions from image. Please give me any suggestions on it.

Answer 1

Marvin provides a method exactly for this purpose.

public static java.util.List<MarvinSegment> findTextRegions(MarvinImage imageIn,
                                        int maxWhiteSpace,
                                        int maxFontLineWidth,
                                        int minTextWidth,
                                        int grayScaleThreshold)

Input image:

Output image:

Source code:

import static marvin.MarvinPluginCollection.*;

public class TextRegions{

        public static void main(String[] args) {

        MarvinImage image = MarvinImageIO.loadImage("./res/passport.png");
        MarvinImage originalImage = image.clone();
        List<MarvinSegment> segments = findTextRegions(image, 15, 8, 30, 150);

        for(MarvinSegment s:segments){
            if(s.height >= 5){
                originalImage.drawRect(s.x1, s.y1, s.x2-s.x1, s.y2-s.y1, Color.red);
            }
        }

        MarvinImageIO.saveImage(originalImage, "./res/passport_2.png");
    }
}

Answer 2

Your best bet is to use OpenCV (there are bindings for Java).

The problem is hard and there's no solution that works in all cases. I would check suggestions from threads like this one and try to find the best solution for your specific case.