45 lines
924 B
Go
45 lines
924 B
Go
package vision
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import (
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"image"
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"math/bits"
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"github.com/disintegration/imaging"
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)
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// PHash 计算图像的感知哈希值 (Perceptual Hash)
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// 返回 64 位整数。Hamming 距离越小，图片越相似。
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func PHash(img image.Image) uint64 {
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// 1. 缩小尺寸到 8x8
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resized := imaging.Resize(img, 8, 8, imaging.Lanczos)
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// 2. 转为灰度
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gray := imaging.Grayscale(resized)
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// 3. 计算像素平均值
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var sum uint64
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pixels := make([]uint8, 64)
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for y := 0; y < 8; y++ {
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for x := 0; x < 8; x++ {
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r, _, _, _ := gray.At(x, y).RGBA()
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v := uint8(r >> 8)
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pixels[y*8+x] = v
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sum += uint64(v)
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}
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}
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avg := uint8(sum / 64)
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// 4. 根据平均值生成哈希
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var hash uint64
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for i, v := range pixels {
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if v >= avg {
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hash |= (1 << uint(i))
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}
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}
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return hash
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}
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// Distance 计算两个哈希值之间的 Hamming 距离
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func Distance(h1, h2 uint64) int {
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return bits.OnesCount64(h1 ^ h2)
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}
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