83 lines
3.2 KiB
Scala
83 lines
3.2 KiB
Scala
import java.awt.image._
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import java.io.File
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import javax.imageio._
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object HoughTransform extends App {
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override def main(args: Array[String]) {
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val inputData = readDataFromImage(args(0))
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val minContrast = if (args.length >= 4) 64 else args(4).toInt
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inputData(args(2).toInt, args(3).toInt, minContrast).writeOutputImage(args(1))
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}
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private def readDataFromImage(filename: String) = {
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val image = ImageIO.read(new File(filename))
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val width = image.getWidth
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val height = image.getHeight
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val rgbData = image.getRGB(0, 0, width, height, null, 0, width)
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val arrayData = new ArrayData(width, height)
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for (y <- 0 until height; x <- 0 until width) {
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var rgb = rgbData(y * width + x)
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rgb = (((rgb & 0xFF0000) >>> 16) * 0.30 + ((rgb & 0xFF00) >>> 8) * 0.59 +
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(rgb & 0xFF) * 0.11).toInt
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arrayData(x, height - 1 - y) = rgb
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}
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arrayData
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}
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}
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class ArrayData(val width: Int, val height: Int) {
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def update(x: Int, y: Int, value: Int) {
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dataArray(x)(y) = value
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}
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def apply(thetaAxisSize: Int, rAxisSize: Int, minContrast: Int) = {
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val maxRadius = Math.ceil(Math.hypot(width, height)).toInt
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val halfRAxisSize = rAxisSize >>> 1
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val outputData = new ArrayData(thetaAxisSize, rAxisSize)
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val sinTable = Array.ofDim[Double](thetaAxisSize)
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val cosTable = sinTable.clone()
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for (theta <- thetaAxisSize - 1 until -1 by -1) {
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val thetaRadians = theta * Math.PI / thetaAxisSize
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sinTable(theta) = Math.sin(thetaRadians)
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cosTable(theta) = Math.cos(thetaRadians)
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}
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for (y <- height - 1 until -1 by -1; x <- width - 1 until -1 by -1)
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if (contrast(x, y, minContrast))
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for (theta <- thetaAxisSize - 1 until -1 by -1) {
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val r = cosTable(theta) * x + sinTable(theta) * y
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val rScaled = Math.round(r * halfRAxisSize / maxRadius).toInt + halfRAxisSize
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outputData.dataArray(theta)(rScaled) += 1
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}
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outputData
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}
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def writeOutputImage(filename: String) {
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var max = Int.MinValue
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for (y <- 0 until height; x <- 0 until width) {
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val v = dataArray(x)(y)
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if (v > max) max = v
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}
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val image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB)
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for (y <- 0 until height; x <- 0 until width) {
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val n = Math.min(Math.round(dataArray(x)(y) * 255.0 / max).toInt, 255)
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image.setRGB(x, height - 1 - y, (n << 16) | (n << 8) | 0x90 | -0x01000000)
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}
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ImageIO.write(image, "PNG", new File(filename))
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}
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private def contrast(x: Int, y: Int, minContrast: Int): Boolean = {
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val centerValue = dataArray(x)(y)
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for (i <- 8 until -1 by -1 if i != 4) {
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val newx = x + (i % 3) - 1
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val newy = y + (i / 3) - 1
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if (newx >= 0 && newx < width && newy >= 0 && newy < height &&
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Math.abs(dataArray(newx)(newy) - centerValue) >= minContrast)
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return true
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}
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false
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}
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private val dataArray = Array.ofDim[Int](width, height)
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}
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