82 lines
1.9 KiB
Go
82 lines
1.9 KiB
Go
package common
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import (
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"image"
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"image/color"
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"math/bits"
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"math/rand"
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"testing"
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)
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func noiseImg(seed int64) *image.Gray {
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rng := rand.New(rand.NewSource(seed))
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img := image.NewGray(image.Rect(0, 0, 160, 120))
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for i := range img.Pix {
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img.Pix[i] = uint8(rng.Intn(256))
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}
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return img
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}
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func hamming(a, b uint64) int {
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return bits.OnesCount64(a ^ b)
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}
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// TestImageDHash64：同图哈希恒等，异噪声图哈希距离应远超相似阈值(8)
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func TestImageDHash64(t *testing.T) {
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h1, err := hashOf(noiseImg(1))
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if err != nil {
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t.Fatalf("hashOf noise: %v", err)
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}
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h2, err := hashOf(noiseImg(1))
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if err != nil {
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t.Fatalf("hashOf same noise: %v", err)
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}
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if h1 != h2 {
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t.Fatalf("same image hash mismatch: %d vs %d", h1, h2)
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}
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h3, err := hashOf(noiseImg(2))
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if err != nil {
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t.Fatalf("hashOf other noise: %v", err)
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}
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if d := hamming(h1, h3); d <= 8 { // 64 位随机噪声期望距离 ~32
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t.Fatalf("unrelated images too close: hamming=%d", d)
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}
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}
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// TestImageDHash64Uniform：纯色图哈希为 0（全等帧），与另一纯色图判为同图属预期
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func TestImageDHash64Uniform(t *testing.T) {
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u := image.NewGray(image.Rect(0, 0, 64, 64))
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for i := range u.Pix {
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u.Pix[i] = 128
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}
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h, err := hashOf(u)
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if err != nil {
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t.Fatalf("hashOf uniform: %v", err)
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}
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if h != 0 {
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t.Fatalf("uniform image hash = %d, want 0", h)
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}
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}
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// 灰度渐变图（列渐变：左暗右亮）
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func gradientImg() *image.Gray {
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img := image.NewGray(image.Rect(0, 0, 90, 80))
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for y := 0; y < 80; y++ {
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for x := 0; x < 90; x++ {
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img.SetGray(x, y, color.Gray{Y: uint8(x * 255 / 89)})
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}
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}
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return img
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}
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// TestImageDHash64Gradient：行渐变每对相邻列左<右，64 位全 1
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func TestImageDHash64Gradient(t *testing.T) {
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h, err := hashOf(gradientImg())
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if err != nil {
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t.Fatalf("hashOf gradient: %v", err)
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}
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if bits.OnesCount64(h) != 64 {
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t.Fatalf("gradient hash bits = %d, want 64 (all 1s)", bits.OnesCount64(h))
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}
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}
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