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52 lines
1.3 KiB
52 lines
1.3 KiB
package com.sothr.imagetools.hash.`type`
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import grizzled.slf4j.Logging
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/**
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* Speedy AHash Perceptual Hashing
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* Uses the average value of the pixels as a baseline to determine the structure of the image
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*
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* Created by dev on 1/22/14.
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*/
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object AHash extends PerceptualHasher with Logging {
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def getHash(imageData: Array[Array[Int]]): Long = {
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trace("Generating AHash")
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val width = imageData.length
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val height = imageData(0).length
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trace(s"Image data size: ${width}x$height")
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/*
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Average Pixel Calculation
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*/
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var total = 0
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for (row <- 0 until height) {
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for (col <- 0 until width) {
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total += imageData(row)(col)
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}
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}
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val mean = total / (height * width)
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/*
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For each pixel, if it is at or above the average, store it as a one, else store it as a zero
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*/
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var hash = 0L
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for (row <- 0 until height by 2) {
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for (col <- 0 until width by 1) {
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hash <<= 1
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val pixel = imageData(row)(col)
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if (pixel >= mean) hash |= 1 else hash |= 0
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}
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if ((row + 1) < width) {
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val nextRow = row + 1
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for (col <- (width - 1) to 0 by -1) {
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hash <<= 1
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val pixel = imageData(nextRow)(col)
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if (pixel >= mean) hash |= 1 else hash |= 0
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}
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}
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}
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debug(s"Computed AHash: $hash from ${width * height} pixels")
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hash
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}
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}
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