1 files changed, 261 insertions, 0 deletions
diff --git a/line-conf-buckets-tess/line-conf-buckets-tess.go b/line-conf-buckets-tess/line-conf-buckets-tess.go
new file mode 100644
index 0000000..29df9f4
--- /dev/null
+++ b/line-conf-buckets-tess/line-conf-buckets-tess.go
@@ -0,0 +1,261 @@
+package main
+
+// TODO: combine this with line-conf-buckets, separating the parsing
+//       out to a separate library, probably
+// see https://github.com/OCR-D/ocrd-train/issues/7 and https://github.com/OCR-D/ocrd-train/
+// for tips on creating lines of tif/txt. best thing is to use hocr-extract-images to extract
+// images for each line, based on tesseract's hocr output. can then copy the ground truth
+// for that
+// initial plan for this is to identify the lines which are best, and extract the text, then
+// later can extract the images from them
+//
+// ok, am parsing the hocr now, workflow should be:
+// - run hocr-extract-images (outside of this) and have a directory of images named line-000.png
+// - run this with hocr and hocr-images dir
+//   this then saves the text for the line alongside copying the image from the dir into a fresh dir, according to the line confidence
+//
+// actually, *should* be able to extract the images quite straightforwardly straight from go, which would be cool. so try to build that.
+// should be super easy, with SubImage, see end of https://blog.golang.org/go-image-package
+
+import (
+	"encoding/xml"
+	"flag"
+	"fmt"
+	"image"
+	"image/png"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+type LineDetail struct {
+	name string
+	avgconf float64
+	img image.Image
+	text string
+	hocrname string
+}
+
+type LineDetails []LineDetail
+
+// Used by sort.Sort.
+func (l LineDetails) Len() int { return len(l) }
+
+// Used by sort.Sort.
+func (l LineDetails) Less(i, j int) bool {
+	return l[i].avgconf < l[j].avgconf
+}
+
+// Used by sort.Sort.
+func (l LineDetails) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
+
+func copyline(filebase string, dirname string, basename string, avgconf string, outdir string, todir string) (err error) {
+	outname := filepath.Join(outdir, todir, filepath.Base(dirname) + "_" + basename + "_" + avgconf)
+	//log.Fatalf("I'd use '%s' as outname, and '%s' as filebase\n", outname, filebase)
+
+	for _, extn := range []string{".bin.png", ".txt"} {
+		infile, err := os.Open(filebase + extn)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to open %s\n", filebase + extn)
+			return err
+		}
+		defer infile.Close()
+
+		err = os.MkdirAll(filepath.Join(outdir, todir), 0700)
+		if err != nil {
+			return err
+		}
+	
+		outfile, err := os.Create(outname + extn)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to create %s\n", outname + extn)
+			return err
+		}
+		defer outfile.Close()
+	
+		_, err = io.Copy(outfile, infile)
+		if err != nil {
+			return err
+		}
+	}
+
+	return err
+}
+
+type Hocr struct {
+	Lines []OcrLine `xml:"body>div>div>p>span"`
+}
+
+type OcrLine struct {
+	Class string `xml:"class,attr"`
+	Id string `xml:"id,attr"`
+	Title string `xml:"title,attr"`
+	Words []OcrWord `xml:"span"`
+	Text string `xml:",chardata"`
+}
+
+type OcrWord struct {
+	Class string `xml:"class,attr"`
+	Id string `xml:"id,attr"`
+	Title string `xml:"title,attr"`
+	// TODO: also capture OcrChar where it exists, to grab text from it
+	// TODO: grab text from these elements, to save for the line
+}
+
+// Returns the confidence for a word based on its x_wconf value
+func wordConf(s string) (float64, error) {
+	re, err := regexp.Compile(`x_wconf ([0-9.]+)`)
+	if err != nil {
+		return 0.0, err
+	}
+	conf := re.FindStringSubmatch(s)
+	return strconv.ParseFloat(conf[1], 64)
+}
+
+func boxCoords(s string) ([4]int, error) {
+	var coords [4]int
+	re, err := regexp.Compile(`bbox ([0-9]+) ([0-9]+) ([0-9]+) ([0-9]+)`)
+	if err != nil {
+		return coords, err
+	}
+	coordstr := re.FindStringSubmatch(s)
+	for i := range coords {
+		c, err := strconv.Atoi(coordstr[i+1])
+		if err != nil {
+			return coords, err
+		}
+		coords[i] = c
+	}
+	return coords, nil
+	
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: line-conf-buckets hocr1 [hocr2] [...]\n")
+		fmt.Fprintf(os.Stderr, "Copies image-text line pairs into different directories according\n")
+		fmt.Fprintf(os.Stderr, "to the average character probability for the line.\n")
+		flag.PrintDefaults()
+	}
+	flag.Parse()
+	if flag.NArg() < 1 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	lines := make(LineDetails, 0)
+
+	var hocr Hocr
+
+	for _, f := range flag.Args() {
+		file, err := ioutil.ReadFile(f)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = xml.Unmarshal(file, &hocr)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		pngfn := strings.Replace(f, ".hocr", ".png", 1)
+		pngf, err := os.Open(pngfn)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer pngf.Close()
+		img, err := png.Decode(pngf)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for _, l := range hocr.Lines {
+			totalconf := float64(0)
+			num := 0
+			for _, w := range l.Words {
+				c, err := wordConf(w.Title)
+				if err != nil {
+					log.Fatal(err)
+				}
+				num++
+				totalconf += c
+			}
+
+			coords, err := boxCoords(l.Title)
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			var line LineDetail
+			line.name = l.Id
+			line.avgconf = totalconf/float64(num)
+			line.text = l.Text // TODO: get text from OcrWord and OcrChar (if available)
+			line.hocrname = strings.Replace(filepath.Base(f), ".hocr", "", 1)
+			line.img = img.(*image.Gray).SubImage(image.Rect(coords[0], coords[1], coords[2], coords[3]))
+			lines = append(lines, line)
+		}
+	}
+
+	sort.Sort(lines)
+
+	worstnum := 0
+	mediumnum := 0
+	bestnum := 0
+
+	outdir := "buckets" // TODO: set this from cmdline
+	todir := ""
+
+	for _, l := range lines {
+		switch {
+		case l.avgconf < 0.95: 
+			todir = "bad"
+			worstnum++
+		case l.avgconf < 0.98:
+			todir = "95to98"
+			mediumnum++
+		default:
+			todir = "98plus"
+			bestnum++
+		}
+
+		avgstr := strconv.FormatFloat(l.avgconf, 'G', -1, 64)
+		avgstr = strings.Replace(avgstr, ".", "", 1)
+		fmt.Printf("Line: %s, avg: %f, avgstr: %s\n", l.name, l.avgconf, avgstr)
+		outname := filepath.Join(outdir, todir, l.hocrname + "_" + l.name + "_" + avgstr + ".png")
+
+		err := os.MkdirAll(filepath.Join(outdir, todir), 0700)
+		if err != nil {
+			log.Fatal(err)
+		}
+	
+		outfile, err := os.Create(outname)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to create %s\n", outname)
+			log.Fatal(err)
+		}
+		defer outfile.Close()
+
+		err = png.Encode(outfile, l.img)
+		if err != nil {
+			log.Fatal(err)
+		}
+		// TODO: do same with saving line
+
+		// TODO: copy the line.img and line.text into the appropriate place, using hocrname/name.ext
+		// TODO: test whether the line.img works properly with multiple hocrs, as it could be that as it's a pointer, it always points to the latest image (don't think so, but not sure)
+	}
+
+	total := worstnum + mediumnum + bestnum
+
+	fmt.Printf("Copied lines to %s\n", outdir)
+	fmt.Printf("---------------------------------\n")
+	fmt.Printf("Lines 98%%+ quality:     %d%%\n", 100 * bestnum / total)
+	fmt.Printf("Lines 95-98%% quality:   %d%%\n", 100 * mediumnum / total)
+	fmt.Printf("Lines <95%% quality:     %d%%\n", 100 * worstnum / total)
+}