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-rw-r--r--integral_test.go185
1 files changed, 185 insertions, 0 deletions
diff --git a/integral_test.go b/integral_test.go
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index 0000000..513c7c4
--- /dev/null
+++ b/integral_test.go
@@ -0,0 +1,185 @@
+// Copyright 2020 Nick White.
+// Use of this source code is governed by the GPLv3
+// license that can be found in the LICENSE file.
+
+package integral
+
+import (
+ "image"
+ "image/draw"
+ _ "image/png"
+ "os"
+ "testing"
+)
+
+func TestFromPNG(t *testing.T) {
+ f, err := os.Open("testdata/in.png")
+ if err != nil {
+ t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
+ }
+ defer f.Close()
+ img, _, err := image.Decode(f)
+ if err != nil {
+ t.Fatalf("Could not decode image: %v\n", err)
+ }
+ b := img.Bounds()
+
+ integral := NewImage(b)
+ draw.Draw(integral, b, img, b.Min, draw.Src)
+
+ if !imgsequal(img, integral) {
+ t.Errorf("Read png image differs to integral image\n")
+ }
+}
+
+func TestSqFromPNG(t *testing.T) {
+ f, err := os.Open("testdata/in.png")
+ if err != nil {
+ t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
+ }
+ defer f.Close()
+ img, _, err := image.Decode(f)
+ if err != nil {
+ t.Fatalf("Could not decode image: %v\n", err)
+ }
+ b := img.Bounds()
+
+ integral := NewSqImage(b)
+ draw.Draw(integral, b, img, b.Min, draw.Src)
+
+ if !imgsequal(img, integral) {
+ t.Errorf("Read png image differs to square integral image\n")
+ }
+}
+
+func TestSum(t *testing.T) {
+ f, err := os.Open("testdata/in.png")
+ if err != nil {
+ t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
+ }
+ defer f.Close()
+ img, _, err := image.Decode(f)
+ if err != nil {
+ t.Fatalf("Could not decode image: %v\n", err)
+ }
+ b := img.Bounds()
+
+ imgplus := newGray16Plus(b)
+ integral := NewImage(b)
+
+ draw.Draw(imgplus, b, img, b.Min, draw.Src)
+ draw.Draw(integral, b, img, b.Min, draw.Src)
+
+ cases := []struct {
+ name string
+ r image.Rectangle
+ }{
+ {"fullimage", b},
+ {"small", image.Rect(1, 1, 5, 5)},
+ {"toobig", image.Rect(0, 0, 2000, b.Dy())},
+ {"toosmall", image.Rect(-1, -1, 4, 5)},
+ {"small2", image.Rect(0, 0, 4, 4)},
+ }
+
+ for _, c := range cases {
+ t.Run(c.name, func(t *testing.T) {
+ sumimg := imgplus.sum(c.r)
+ sumint := integral.Sum(c.r)
+ if sumimg != sumint {
+ t.Errorf("Sum of integral image differs to regular image: regular: %d, integral: %d\n", sumimg, sumint)
+ }
+ })
+ }
+}
+
+func TestMean(t *testing.T) {
+ f, err := os.Open("testdata/in.png")
+ if err != nil {
+ t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
+ }
+ defer f.Close()
+ img, _, err := image.Decode(f)
+ if err != nil {
+ t.Fatalf("Could not decode image: %v\n", err)
+ }
+ b := img.Bounds()
+
+ imgplus := newGray16Plus(b)
+ integral := NewImage(b)
+
+ draw.Draw(imgplus, b, img, b.Min, draw.Src)
+ draw.Draw(integral, b, img, b.Min, draw.Src)
+
+ cases := []struct {
+ name string
+ r image.Rectangle
+ }{
+ {"fullimage", b},
+ {"small", image.Rect(1, 1, 5, 5)},
+ {"toobig", image.Rect(0, 0, 2000, b.Dy())},
+ {"toosmall", image.Rect(-1, -1, 4, 5)},
+ {"small2", image.Rect(0, 0, 4, 4)},
+ }
+
+ for _, c := range cases {
+ t.Run(c.name, func(t *testing.T) {
+ meanimg := imgplus.mean(c.r)
+ meanint := integral.Mean(c.r)
+ if meanimg != meanint {
+ t.Errorf("Mean of integral image differs to regular image: regular: %f, integral: %f\n", meanimg, meanint)
+ }
+ })
+ }
+}
+
+func imgsequal(img1, img2 image.Image) 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
+}
+
+type grayPlus struct {
+ image.Gray16
+}
+
+func newGray16Plus(r image.Rectangle) *grayPlus {
+ var g grayPlus
+ g.Gray16 = *image.NewGray16(r)
+ return &g
+}
+
+func (i grayPlus) sum(r image.Rectangle) uint64 {
+ var sum uint64
+ for y := r.Min.Y; y < r.Max.Y; y++ {
+ for x := r.Min.X; x < r.Max.X; x++ {
+ c := i.Gray16At(x, y).Y
+ sum += uint64(c)
+ }
+ }
+ return sum
+}
+
+func (i grayPlus) mean(r image.Rectangle) float64 {
+ in := r.Intersect(i.Bounds())
+ return float64(i.sum(r)) / float64(in.Dx()*in.Dy())
+}