2016 Update

Task/Hough-transform/Scala/hough-transform.scala

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