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package binarize
import (
"flag"
"fmt"
"image"
"image/draw"
"image/png"
"os"
"testing"
)
var update = flag.Bool("update", false, "update golden files")
func decode(s string) (*image.Gray, error) {
f, err := os.Open(s)
defer f.Close()
if err != nil {
return nil, err
}
img, err := png.Decode(f)
if err != nil {
return nil, err
}
b := img.Bounds()
gray := image.NewGray(image.Rect(0, 0, b.Dx(), b.Dy()))
draw.Draw(gray, b, img, b.Min, draw.Src)
return gray, nil
}
func imgsequal(img1 *image.Gray, img2 *image.Gray) bool {
b := img1.Bounds()
if ! b.Eq(img2.Bounds()) {
return false
}
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
r0, g0, b0, a0 := img1.At(x, y).RGBA()
r1, g1, b1, a1 := img2.At(x, y).RGBA()
if r0 != r1 {
return false
}
if g0 != g1 {
return false
}
if b0 != b1 {
return false
}
if a0 != a1 {
return false
}
}
}
return true
}
func TestBinarization(t *testing.T) {
cases := []struct {
name string
orig string
golden string
ksize float64
wsize int
}{
{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.5_w41.png", 0.5, 41},
{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.5_w19.png", 0.5, 19},
{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.3_w19.png", 0.3, 19},
{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.5_w41.png", 0.5, 41},
{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.5_w19.png", 0.5, 19},
{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.3_w19.png", 0.3, 19},
}
for _, c := range cases {
t.Run(fmt.Sprintf("%s_%0.1f_%d", c.name, c.ksize, c.wsize), func(t *testing.T) {
var actual *image.Gray
orig, err := decode(c.orig)
if err != nil {
t.Errorf("Could not open file %s: %v\n", c.orig, err)
}
switch c.name {
case "integralsauvola":
actual = IntegralSauvola(orig, c.ksize, c.wsize)
case "sauvola":
actual = Sauvola(orig, c.ksize, c.wsize)
default:
t.Fatalf("No method %s\n", c.name)
}
if *update {
f, err := os.Create(c.golden)
defer f.Close()
if err != nil {
t.Errorf("Could not open file %s to update: %v\n", c.golden, err)
}
err = png.Encode(f, actual)
if err != nil {
t.Errorf("Could not encode update of %s: %v\n", c.golden, err)
}
}
golden, err := decode(c.golden)
if err != nil {
t.Errorf("Could not open file %s: %v\n", c.golden, err)
}
if ! imgsequal(golden, actual) {
t.Errorf("Binarized %s differs to %s\n", c.orig, c.golden)
}
})
}
}
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