Package com.itextpdf.pdfocr.onnxtr.detection

Class OnnxDetectionPostProcessor

java.lang.Object

com.itextpdf.pdfocr.onnxtr.detection.OnnxDetectionPostProcessor

All Implemented Interfaces:

IDetectionPostProcessor

       public class OnnxDetectionPostProcessor extends Object implements IDetectionPostProcessor
      

Implementation of a text detection predictor post-processor, used for OnnxTR model outputs.

Current implementation works somewhat like this:

1. Model output is binarized and then cleaned-up via erosion and dilation.
2. Large-enough contours from the image in the previous step are found.
3. Contours with less certainty score are discarded.
4. Remaining contours are wrapped into boxes with relative [0, 1] coordinates.

Constructor Summary

Constructors

Constructor	Description
OnnxDetectionPostProcessor()	Creates a new post-processor with the default threshold values.
OnnxDetectionPostProcessor(float binarizationThreshold, float scoreThreshold)	Creates a new post-processor.

Method Summary

Modifier and Type	Method	Description
List	process(BufferedImage input, FloatBufferMdArray output)	Process ML model output for a specified image and return a list of detected objects.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

OnnxDetectionPostProcessor

             public OnnxDetectionPostProcessor
             (float binarizationThreshold, float scoreThreshold)
            

Creates a new post-processor.

Parameters:

binarizationThreshold - threshold value used, when binarizing a monochromatic image. If pixel value is greater or equal to the threshold, it is mapped to 1, otherwise it is mapped to 0

scoreThreshold - score threshold for a detected box. If score is lower than this value, the box gets discarded

OnnxDetectionPostProcessor

             public OnnxDetectionPostProcessor()
            

Creates a new post-processor with the default threshold values.

Method Details

process

             public List process
             (BufferedImage input, FloatBufferMdArray output)
            

Process ML model output for a specified image and return a list of detected objects.

Specified by:

process in interface IDetectionPostProcessor

Parameters:

input - input image, which was used to produce the inputs to the ML model

output - normalized output of the ML model

Returns:

a list of detected objects. See interface documentation for more information