100 lines
2.9 KiB
Go
100 lines
2.9 KiB
Go
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package imageproc
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import (
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"image"
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"math"
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"sort"
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"materialanalyzer/internal/model"
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)
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func ExtractCanonicalStatistics(img image.Image, visual model.VisualFeatures, texture model.TextureFeatures) model.CanonicalStatistics {
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samples := collectSamples(img, 65000)
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stats := model.CanonicalStatistics{
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MeanRGB: visual.AverageRGB,
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DominantOrientationDeg: texture.PrimaryOrientationDeg,
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BrightnessHistogramBins: 16,
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GradientHistogramBins: 18,
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BrightnessDistribution: make([]float64, 16),
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GradientHistogram: make([]float64, 18),
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}
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if len(samples) == 0 {
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return stats
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}
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rs := make([]int, len(samples))
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gs := make([]int, len(samples))
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bs := make([]int, len(samples))
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var varianceSum float64
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for i, s := range samples {
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rs[i] = int(math.Round(s.r))
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gs[i] = int(math.Round(s.g))
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bs[i] = int(math.Round(s.b))
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dr := s.r - float64(visual.AverageRGB.R)
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dg := s.g - float64(visual.AverageRGB.G)
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db := s.b - float64(visual.AverageRGB.B)
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varianceSum += (dr*dr + dg*dg + db*db) / 3
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bin := min(len(stats.BrightnessDistribution)-1, int((s.lum/255.0)*float64(len(stats.BrightnessDistribution))))
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stats.BrightnessDistribution[bin]++
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}
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sort.Ints(rs)
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sort.Ints(gs)
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sort.Ints(bs)
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mid := len(samples) / 2
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stats.MedianRGB = model.RGB{R: rs[mid], G: gs[mid], B: bs[mid]}
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stats.ColorVariance = round4(varianceSum / float64(len(samples)) / (255.0 * 255.0))
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for i := range stats.BrightnessDistribution {
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stats.BrightnessDistribution[i] = round6(stats.BrightnessDistribution[i] / float64(len(samples)))
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}
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stats.TextureVariance, stats.GradientHistogram = gradientStatistics(img, len(stats.GradientHistogram))
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return stats
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}
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func gradientStatistics(img image.Image, bins int) (float64, []float64) {
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small := ResizeToMax(img, 384)
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gray, w, h := grayscale(small)
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hist := make([]float64, bins)
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if w < 3 || h < 3 || bins <= 0 {
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return 0, hist
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}
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var mags []float64
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var totalWeight float64
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for y := 1; y < h-1; y++ {
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for x := 1; x < w-1; x++ {
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gx := -int(gray[(y-1)*w+x-1]) + int(gray[(y-1)*w+x+1]) -
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2*int(gray[y*w+x-1]) + 2*int(gray[y*w+x+1]) -
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int(gray[(y+1)*w+x-1]) + int(gray[(y+1)*w+x+1])
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gy := -int(gray[(y-1)*w+x-1]) - 2*int(gray[(y-1)*w+x]) - int(gray[(y-1)*w+x+1]) +
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int(gray[(y+1)*w+x-1]) + 2*int(gray[(y+1)*w+x]) + int(gray[(y+1)*w+x+1])
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mag := math.Hypot(float64(gx), float64(gy))
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mags = append(mags, mag)
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angle := math.Atan2(float64(gy), float64(gx)) + math.Pi/2
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deg := math.Mod(angle*180/math.Pi+180, 180)
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bin := min(bins-1, int(deg/180*float64(bins)))
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hist[bin] += mag
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totalWeight += mag
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}
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}
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if len(mags) == 0 {
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return 0, hist
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}
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var mean, variance float64
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for _, mag := range mags {
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mean += mag
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}
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mean /= float64(len(mags))
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for _, mag := range mags {
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d := mag - mean
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variance += d * d
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}
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variance = variance / float64(len(mags)) / (1020.0 * 1020.0)
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if totalWeight > 0 {
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for i := range hist {
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hist[i] = round6(hist[i] / totalWeight)
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}
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}
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return round4(variance), hist
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}
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