Hough transform: Difference between revisions
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* See [[Example:Hough transform/Tcl]]
=={{header|Wren}}==
{{trans|Kotlin}}
{{libheader|DOME}}
<lang ecmascript>import "graphics" for Canvas, Color, ImageData
import "dome" for Window, Process
import "math" for Math
var Hypot = Fn.new { |x, y| (x*x + y*y).sqrt }
class ArrayData {
construct new(width, height) {
_width = width
_height = height
_dataArray = List.filled(width * height, 0)
}
width { _width }
height { _height }
[x, y] { _dataArray[y * _width + x] }
[x, y]=(v) { _dataArray[y * _width + x] = v }
transform(thetaAxisSize, rAxisSize, minContrast) {
var maxRadius = Math.ceil(Hypot.call(_width, _height))
var halfRAxisSize = rAxisSize >> 1
var outputData = ArrayData.new(thetaAxisSize, rAxisSize)
// x output ranges from 0 to pi
// y output ranges from -maxRadius to maxRadius
var sinTable = List.filled(thetaAxisSize, 0)
var cosTable = List.filled(thetaAxisSize, 0)
for (theta in thetaAxisSize - 1..0) {
var thetaRadians = theta * Num.pi / thetaAxisSize
sinTable[theta] = Math.sin(thetaRadians)
cosTable[theta] = Math.cos(thetaRadians)
}
for (y in _height - 1..0) {
for (x in _width - 1..0) {
if (contrast(x, y, minContrast)) {
for (theta in thetaAxisSize - 1..0) {
var r = cosTable[theta] * x + sinTable[theta] * y
var rScaled = Math.round(r * halfRAxisSize / maxRadius) + halfRAxisSize
outputData.accumulate(theta, rScaled, 1)
}
}
}
}
return outputData
}
accumulate(x, y, delta) { this[x, y] = this[x, y] + delta }
contrast(x, y, minContrast) {
var centerValue = this[x, y]
for (i in 8..0) {
if (i != 4) {
var newx = x + i % 3 - 1
var newy = y + (i / 3).truncate - 1
if (newx >= 0 && newx < width && newy >= 0 && newy < height &&
Math.abs(this[newx, newy] - centerValue) >= minContrast) return true
}
}
return false
}
max {
var max = _dataArray[0]
for (i in width * height - 1..1) {
if (_dataArray[i] > max) max = _dataArray[i]
}
return max
}
}
class HoughTransform {
construct new(inFile, outFile, width, height, minCont) {
Window.title = "Hough Transform"
Window.resize(width, height)
Canvas.resize(width, height)
_width = width
_height = height
_inFile = inFile
_outFile = outFile
_minCont = minCont
}
init() {
var dataArray = readInputFromImage(_inFile)
dataArray = dataArray.transform(_width, _height, _minCont)
writeOutputImage(_outFile, dataArray)
}
readInputFromImage(filename) {
var inputImage = ImageData.loadFromFile(filename)
var width = inputImage.width
var height = inputImage.height
var rgbData = []
for (y in 0...height) {
for (x in 0...width) rgbData.add(inputImage.pget(x, y))
}
var arrayData = ArrayData.new(width, height)
// Flip y axis when reading image
for (y in 0...height) {
for (x in 0...width) {
var rgbValue = rgbData[y * width + x]
rgbValue = (rgbValue.r * 0.3 + rgbValue.g * 0.59 + rgbValue.b * 0.11).floor
arrayData[x, height - 1 - y] = rgbValue
}
}
return arrayData
}
writeOutputImage(filename, arrayData) {
var max = arrayData.max
var outputImage = ImageData.create(filename, arrayData.width, arrayData.height)
for (y in 0...arrayData.height) {
for (x in 0...arrayData.width) {
var n = Math.min(Math.round(arrayData[x, y] * 255 / max), 255)
var c = Color.new(n, n, 0x90)
outputImage.pset(x, arrayData.height - 1 - y, c)
}
}
outputImage.draw(0, 0)
outputImage.saveToFile(filename)
}
update() {}
draw(alpha) {}
}
var args = Process.args
System.print(args)
if (args.count != 7) Fiber.abort("There should be exactly 5 command line arguments.")
var inFile = args[2]
var outFile = args[3]
var width = Num.fromString(args[4])
var height = Num.fromString(args[5])
var minCont = Num.fromString(args[6])
var Game = HoughTransform.new(inFile, outFile, width, height, minCont)</lang>
{{out}}
<pre>
When called with: 'dome hough_transform.wren Pentagon.png Pentagon2.png 640 480 100' the resulting image is similar to that of the Java entry.
</pre>
=={{header|zkl}}==
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