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-rw-r--r--hocr/hocr.go170
1 files changed, 170 insertions, 0 deletions
diff --git a/hocr/hocr.go b/hocr/hocr.go
new file mode 100644
index 0000000..4384bad
--- /dev/null
+++ b/hocr/hocr.go
@@ -0,0 +1,170 @@
+package hocr
+
+// TODO: separate out linedetail to a general structure that can incorporate
+// line-conf-buckets too, in a different file (and rename package to
+// something more generic). Try to use interfaces to fill it with hocr
+// or ocropy data simply. Could design it so LineDetail is an interface,
+// that can do CopyLines() and BucketUp(). Actually only BucketUp() would
+// be needed, as copylines can be internal to that. Then can create more
+// methods as and when needed. BucketUp() can take some form of arguments
+// that can make it flexible, like []struct { dirname string, minconf float64 }
+// TODO: Parse line name to zero pad line numbers, so they come out in the correct order
+
+import (
+ "encoding/xml"
+ "image"
+ "regexp"
+ "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] }
+
+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"`
+ Chars []OcrChar `xml:"span"`
+ Text string `xml:",chardata"`
+}
+
+type OcrChar struct {
+ Class string `xml:"class,attr"`
+ Id string `xml:"id,attr"`
+ Title string `xml:"title,attr"`
+ Chars []OcrChar `xml:"span"`
+ Text string `xml:",chardata"`
+}
+
+// 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 noText(s string) bool {
+ t := strings.Trim(s, " \n")
+ return len(t) == 0
+}
+
+func Parse(b []byte) (Hocr, error) {
+ var hocr Hocr
+
+ err := xml.Unmarshal(b, &hocr)
+ if err != nil {
+ return hocr, err
+ }
+
+ return hocr, nil
+}
+
+func GetLineDetails(h Hocr, i image.Image, name string) (LineDetails, error) {
+ lines := make(LineDetails, 0)
+
+ for _, l := range h.Lines {
+ totalconf := float64(0)
+ num := 0
+ for _, w := range l.Words {
+ c, err := wordConf(w.Title)
+ if err != nil {
+ return lines, err
+ }
+ num++
+ totalconf += c
+ }
+
+ coords, err := boxCoords(l.Title)
+ if err != nil {
+ return lines, err
+ }
+
+ var line LineDetail
+ line.Name = l.Id
+ line.Avgconf = (totalconf/float64(num)) / 100
+ linetext := ""
+
+ linetext = l.Text
+ if(noText(linetext)) {
+ linetext = ""
+ for _, w := range l.Words {
+ if(w.Class != "ocrx_word") {
+ continue
+ }
+ linetext += w.Text + " "
+ }
+ }
+ if(noText(linetext)) {
+ linetext = ""
+ for _, w := range l.Words {
+ if(w.Class != "ocrx_word") {
+ continue
+ }
+ for _, c := range w.Chars {
+ if(c.Class != "ocrx_cinfo") {
+ continue
+ }
+ linetext += c.Text
+ }
+ linetext += " "
+ }
+ }
+ line.Text = strings.TrimRight(linetext, " ")
+ line.Text += "\n"
+ line.Hocrname = name
+ line.Img = i.(*image.Gray).SubImage(image.Rect(coords[0], coords[1], coords[2], coords[3]))
+ lines = append(lines, line)
+ }
+ return lines, nil
+}