22 lines
492 B
Go
22 lines
492 B
Go
package filter
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import (
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"image"
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"image/color"
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"math"
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)
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func Sigmoid(src *image.Gray, contrast, midpoint float64) *image.Gray {
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b := src.Bounds()
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out := image.NewGray(b)
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for y := b.Min.Y; y < b.Max.Y; y++ {
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for x := b.Min.X; x < b.Max.X; x++ {
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v := float64(src.GrayAt(x, y).Y) / 255.0
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adj := 1.0 / (1.0 + math.Exp(contrast*(midpoint-v)))
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out.SetGray(x, y, color.Gray{Y: uint8(adj * 255)})
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}
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}
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return out
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}
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