Tess4J：如何使用 ResultIterator？

Question

我正在將我的 OCR 應用程序從 C++ 轉換為 Java。 使用 Tess4J 我想獲得每個單詞的邊界框。 然而，顯然 TessResultIterator 不提供任何方法。 所以我想知道是否有可能以某種方式獲得這些數據？

這是我當前的代碼：

TessBaseAPI api = TessAPI1.TessBaseAPICreate();
TessAPI1.TessBaseAPIInit3(api, path, lang);
TessAPI1.TessBaseAPISetPageSegMode(api, TessAPI1.TessPageSegMode.PSM_AUTO);
TessAPI1.TessBaseAPISetImage(api, img, w, h, bpp, bpp*w);
TessAPI1.TessBaseAPIGetUTF8Text(api);
TessResultIterator it = TessAPI1.TessBaseAPIGetIterator(api); 

在 C++ 中，我可以這樣繼續：

char* text = it->GetUTF8Text(tesseract::RIL_WORD); 
int left, top, right, bttm;
it->BoundingBox(tesseract::RIL_WORD, &left, &top, &right, &bttm); 

Answer 1

你可以試試下面的代碼片段嗎？ 我沒有真正徹底地測試它。

TessResultIterator ri = TessAPI1.TessBaseAPIGetIterator(api);
TessPageIterator pi = TessAPI1.TessResultIteratorGetPageIterator(ri);
String str = TessAPI1.TessResultIteratorGetUTF8Text(ri, TessPageIteratorLevel.RIL_WORD);
IntBuffer leftB = IntBuffer.allocate(1);
IntBuffer topB = IntBuffer.allocate(1);
IntBuffer rightB = IntBuffer.allocate(1);
IntBuffer bottomB = IntBuffer.allocate(1);
TessAPI1.TessPageIteratorBoundingBox(pi, TessPageIteratorLevel.RIL_WORD, leftB, topB, rightB, bottomB);
int left = leftB.get();
int top = topB.get();
int right = rightB.get();
int bottom = bottomB.get();

Answer 2

以下方法取自Tess4J的GitHub 頁面，它展示了如何迭代輸入文檔中每個匹配單詞的邊界框。 使這段代碼適應您自己的需要應該很容易，例如通過使用您自己的 Tesseract 數據目錄的路徑以及您自己的圖像文件的路徑。

public void testResultIterator() throws Exception {
    File tiff = new File(this.testResourcesDataPath, "eurotext.tif");
    BufferedImage image = ImageIO.read(new FileInputStream(tiff));
    ByteBuffer buf = ImageIOHelper.convertImageData(image);
    int bpp = image.getColorModel().getPixelSize();
    int bytespp = bpp / 8;
    int bytespl = (int) Math.ceil(image.getWidth() * bpp / 8.0);
    TessAPI1.TessBaseAPIInit3(handle, datapath, language);
    TessAPI1.TessBaseAPISetPageSegMode(handle, TessPageSegMode.PSM_AUTO);
    TessAPI1.TessBaseAPISetImage(handle, buf, image.getWidth(), image.getHeight(), bytespp, bytespl);
    ETEXT_DESC monitor = new ETEXT_DESC();
    ITessAPI.TimeVal timeout = new ITessAPI.TimeVal();
    timeout.tv_sec = new NativeLong(0L); // time > 0 causes blank ouput
    monitor.end_time = timeout;
    TessAPI1.TessBaseAPIRecognize(handle, monitor);
    TessResultIterator ri = TessAPI1.TessBaseAPIGetIterator(handle);
    TessPageIterator pi = TessAPI1.TessResultIteratorGetPageIterator(ri);
    TessAPI1.TessPageIteratorBegin(pi);
    int level = TessPageIteratorLevel.RIL_WORD;

    do {
        Pointer ptr = TessAPI1.TessResultIteratorGetUTF8Text(ri, level);
        String word = ptr.getString(0);
        TessAPI1.TessDeleteText(ptr);
        float confidence = TessAPI1.TessResultIteratorConfidence(ri, level);
        IntBuffer leftB = IntBuffer.allocate(1);
        IntBuffer topB = IntBuffer.allocate(1);
        IntBuffer rightB = IntBuffer.allocate(1);
        IntBuffer bottomB = IntBuffer.allocate(1);
        TessAPI1.TessPageIteratorBoundingBox(pi, level, leftB, topB, rightB, bottomB);
        int left = leftB.get();
        int top = topB.get();
        int right = rightB.get();
        int bottom = bottomB.get();
        System.out.print(String.format("%s %d %d %d %d %f", word, left, top, right, bottom, confidence));

        IntBuffer boldB = IntBuffer.allocate(1);
        IntBuffer italicB = IntBuffer.allocate(1);
        IntBuffer underlinedB = IntBuffer.allocate(1);
        IntBuffer monospaceB = IntBuffer.allocate(1);
        IntBuffer serifB = IntBuffer.allocate(1);
        IntBuffer smallcapsB = IntBuffer.allocate(1);
        IntBuffer pointSizeB = IntBuffer.allocate(1);
        IntBuffer fontIdB = IntBuffer.allocate(1);
        String fontName = TessAPI1.TessResultIteratorWordFontAttributes(ri, boldB, italicB, underlinedB,
                monospaceB, serifB, smallcapsB, pointSizeB, fontIdB);
        boolean bold = boldB.get() == TRUE;
        boolean italic = italicB.get() == TRUE;
        boolean underlined = underlinedB.get() == TRUE;
        boolean monospace = monospaceB.get() == TRUE;
        boolean serif = serifB.get() == TRUE;
        boolean smallcaps = smallcapsB.get() == TRUE;
        int pointSize = pointSizeB.get();
        int fontId = fontIdB.get();
        System.out.println(String.format("  font: %s, size: %d, font id: %d, bold: %b,"
                + " italic: %b, underlined: %b, monospace: %b, serif: %b, smallcap: %b", fontName, pointSize,
                fontId, bold, italic, underlined, monospace, serif, smallcaps));
    } while (TessAPI1.TessPageIteratorNext(pi, level) == TRUE);
}

上面腳本的輸出將是一些行，每個匹配的單詞一行，看起來像這樣：

SOME_WORD 65 60 120 83 96.072098 字體：空，大小：32，字體 ID：-1，粗體：假，斜體：假，下划線：假，等寬：假，襯線：假，小寫：假

匹配單詞SOME_WORD之后的前四個數字是左、上、右和下坐標。 接下來是置信度，以百分比形式給出。 然后，還有一些關於文本本身的元數據，包括字體樣式信息。