Hough transform: Difference between revisions
m
→{{header|Wren}}: Minor tidy
(Added Wren) |
m (→{{header|Wren}}: Minor tidy) |
||
(3 intermediate revisions by 2 users not shown) | |||
Line 19:
BBC BASIC uses Cartesian coordinates so the image is 'upside down' compared with some other solutions.
[[Image:hough_bbc.gif|right]]
<
Height% = 240
Line 65:
REPEAT
WAIT 1
UNTIL FALSE</
=={{header|C}}==
Line 74:
{{trans|Go}}
This uses the module from the Grayscale image Task. The output image is the same as in the Go solution.
<
Image!Gray houghTransform(in Image!Gray im,
Line 112:
.houghTransform()
.savePGM("Pentagon_hough.pgm");
}</
=={{header|Go}}==
[[file:GoHough.png|right|thumb|Output png]]
{{trans|Python}}
<
import (
Line 187:
fmt.Println(err)
}
}</
=={{header|Haskell}}==
{{libheader|JuicyPixels}}
<
import Data.Array ((!))
import Data.Array.ST (newArray, writeArray, readArray, runSTArray)
Line 307:
_ ->
putStrLn $
"Usage: " ++ prog ++ " <image-file> <out-file.png> <width> <height>"</
'''Example use:'''
<syntaxhighlight lang="text">HoughTransform Pentagon.png hough.png 360 360</
=={{header|J}}==
'''Solution:'''
<
NB. y is picture as an array with 1 at non-white points,
NB. x is resolution (width,height) of resulting image
Line 323:
rho=. <. 0.5+ h * (rho-min) % max-min NB. Rescale rho from 0 to h and round to int
|.([: <:@(#/.~) (i.h)&,)"1&.|: rho NB. consolidate into picture
)</
[[Image:JHoughTransform.png|320px200px|thumb|right|Resulting viewmat image from J implementation of Hough Transform on sample pentagon image]]'''Example use:'''
<
require 'media/platimg' NB. addon required pre J8
Img=: readimg_jqtide_ jpath '~temp/pentagon.png'
viewmat 460 360 houghTransform _1 > Img</
<br style="clear:both" />
=={{header|Java}}==
'''Code:'''
<
import java.io.File;
import java.io.IOException;
Line 474:
return;
}
}</
[[Image:JavaHoughTransform.png|640px480px|thumb|right|Output from example pentagon image]]'''Example use:'''
Line 481:
=={{header|Julia}}==
<
img = fill(false,5,5)
Line 487:
println(hough_transform_standard(img))
</
Tuple{Float64,Float64}[(3.0, 1.5708)]
</pre>
Line 493:
=={{header|Kotlin}}==
{{trans|Java}}
<
import java.io.File
import javax.imageio.ImageIO
Line 584:
val minContrast = if (args.size >= 4) 64 else args[4].toInt()
inputData(args[2].toInt(), args[3].toInt(), minContrast).writeOutputImage(args[1])
}</
=={{header|Maple}}==
<
img := Read("pentagon.png")[..,..,1]:
img_x := Convolution (img, Matrix ([[1,2,1], [0,0,0],[-1,-2,-1]])):
Line 629:
end proc:
result :=HoughTransform(img,row,col);
Embed(Scale(FitIntensity(Create(result)), 1..500,1..500));</
=={{header|Mathematica}} / {{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">
Radon[image, Method -> "Hough"]
</syntaxhighlight>
=={{header|MATLAB}}==
Line 645:
{{libheader|nimPNG}}
We use the modules from tasks “Bitmap” and “Grayscale image”, adding necessary conversions to read and write PNG files.
<
import grayscale_image
Line 697:
for color in houghImage.pixels:
data.add([color.r, color.g, color.b])
discard savePNG24(Output, data, houghImage.w, houghImage.h)</
=={{header|Perl}}==
{{trans|Sidef}}
<
use warnings;
Line 745:
my $ht = hough($img);
$ht->write(file => 'hough_transform.png');
</syntaxhighlight>
=={{header|Phix}}==
{{libheader|Phix/pGUI}}
{{trans|Sidef}}
<!--<syntaxhighlight lang="phix">(notonline)-->
<span style="color: #000080;font-style:italic;">-- demo\rosetta\Hough_transform.exw</span>
<span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- IupImage, imImage, im_width/height/pixel, allocate,
-- imFileImageLoadBitmap, IupImageFromImImage</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">pGUI</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">hypot</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">return</span> <span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">*</span><span style="color: #000000;">a</span><span style="color: #0000FF;">+</span><span style="color: #000000;">b</span><span style="color: #0000FF;">*</span><span style="color: #000000;">b</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">hough_transform</span><span style="color: #0000FF;">(</span><span style="color: #000000;">imImage</span> <span style="color: #000000;">im</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">=</span><span style="color: #000000;">460</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">=</span><span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">height</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">height</span> <span style="color: #0000FF;">/</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">xsize</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">im_width</span><span style="color: #0000FF;">(</span><span style="color: #000000;">im</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">ysize</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">im_height</span><span style="color: #0000FF;">(</span><span style="color: #000000;">im</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">canvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">255</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">),</span><span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">rmax</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">hypot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xsize</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ysize</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">dr</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">*(</span><span style="color: #000000;">rmax</span> <span style="color: #0000FF;">/</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">dth</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">(</span><span style="color: #004600;">PI</span> <span style="color: #0000FF;">/</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">ysize</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">xsize</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">r</span><span style="color: #0000FF;">,</span><span style="color: #000000;">g</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">im_pixel</span><span style="color: #0000FF;">(</span><span style="color: #000000;">im</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">r</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">255</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">width</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">th</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">dth</span><span style="color: #0000FF;">*(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">r2</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">cos</span><span style="color: #0000FF;">(</span><span style="color: #000000;">th</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">sin</span><span style="color: #0000FF;">(</span><span style="color: #000000;">th</span><span style="color: #0000FF;">))</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">iry</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">height</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span> <span style="color: #0000FF;">+</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">r2</span><span style="color: #0000FF;">/</span><span style="color: #000000;">dr</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">0.5</span><span style="color: #0000FF;">))+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">cik</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">canvas</span><span style="color: #0000FF;">[</span><span style="color: #000000;">iry</span><span style="color: #0000FF;">][</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">cik</span><span style="color: #0000FF;">>=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">canvas</span><span style="color: #0000FF;">[</span><span style="color: #000000;">iry</span><span style="color: #0000FF;">][</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cik</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000000;">canvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">flatten</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- (needed by IupImage)</span>
<span style="color: #004080;">Ihandle</span> <span style="color: #000000;">new_img</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupImage</span><span style="color: #0000FF;">(</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">canvas</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">255</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">IupSetStrAttributeId</span><span style="color: #0000FF;">(</span><span style="color: #000000;">new_img</span><span style="color: #0000FF;">,</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%d %d %d"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">c</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">new_img</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #7060A8;">IupOpen</span><span style="color: #0000FF;">()</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">pError</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">allocate</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">machine_word</span><span style="color: #0000FF;">())</span>
<span style="color: #000000;">imImage</span> <span style="color: #000000;">im1</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">imFileImageLoadBitmap</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"Pentagon320.png"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">pError</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">im1</span><span style="color: #0000FF;">=</span><span style="color: #004600;">NULL</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">?</span><span style="color: #008000;">"error opening Pentagon320.png"</span> <span style="color: #7060A8;">abort</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #004080;">Ihandln</span> <span style="color: #000000;">image1</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">IupImageFromImImage</span><span style="color: #0000FF;">(</span><span style="color: #000000;">im1</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">image2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">hough_transform</span><span style="color: #0000FF;">(</span><span style="color: #000000;">im1</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">label1</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupLabel</span><span style="color: #0000FF;">(),</span>
<span style="color: #000000;">label2</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupLabel</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">IupSetAttributeHandle</span><span style="color: #0000FF;">(</span><span style="color: #000000;">label1</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"IMAGE"</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">image1</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupSetAttributeHandle</span><span style="color: #0000FF;">(</span><span style="color: #000000;">label2</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"IMAGE"</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">image2</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">Ihandle</span> <span style="color: #000000;">dlg</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupDialog</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">IupHbox</span><span style="color: #0000FF;">({</span><span style="color: #000000;">label1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">label2</span><span style="color: #0000FF;">}))</span>
<span style="color: #7060A8;">IupSetAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"TITLE"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"Hough transform"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupShow</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span> <span style="color: #000080;font-style:italic;">-- (no chance...)</span>
<span style="color: #7060A8;">IupMainLoop</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">IupClose</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<!--</syntaxhighlight>-->
=={{header|Python}}==
{{libheader|PIL}}
This is the classical Hough transform as described in wikipedia. The code does not compute averages; it merely makes a point on the transformed image darker if a lot of points on the original image lie on the corresponding line. The output is almost identical to that of the Tcl code. The code works only with gray-scale images, but it is easy to extend to RGB.
<
from math import hypot, pi, cos, sin
from PIL import Image
Line 847 ⟶ 852:
if __name__ == "__main__": test()
</syntaxhighlight>
{{omit from|PARI/GP}}
Line 858 ⟶ 863:
The <code>GD</code> module the output palette to 255 colors, so only transform darker pixels in the image.
{{trans|Perl}}
<syntaxhighlight lang="raku"
my $filename = 'pentagon.ppm';
Line 883 ⟶ 888:
my $y = floor $pixel / $xsize;
(
my $th = $dth*$k;
my $r = ($x*cos($th) + $y*sin($th));
Line 895 ⟶ 900:
my $png_fh = $image.open("hough-transform.png", "wb");
$image.output($png_fh, GD_PNG);
$png_fh.close;</
See [https://github.com/thundergnat/rc/blob/master/img/hough-transform.png Hough Transform] (offsite .png image)
=={{header|Ruby}}==
<syntaxhighlight lang="ruby">
require 'mathn'
require 'rubygems'
Line 934 ⟶ 939:
end
out
end</
=={{header|Rust}}==
<
//! Contributed by Gavin Baker <gavinb@antonym.org>
//! Adapted from the Go version
Line 1,077 ⟶ 1,082:
}
</syntaxhighlight>
=={{header|Scala}}==
{{trans|Kotlin}}
<
import java.io.File
import javax.imageio._
Line 1,164 ⟶ 1,169:
private val dataArray = Array.ofDim[Int](width, height)
}</
=={{header|SequenceL}}==
{{trans|Java}}
'''Tail-Recursive SequenceL Code:'''<br>
<
import <Utilities/Math.sl>;
Line 1,213 ⟶ 1,218:
j within x-1 ... x+1;
in
some(some(abs(image[y,x] - neighbors) >= minContrast));</
'''C++ Driver Code:'''<br>
{{libheader|CImg}}
<
#include "CImg.h"
Line 1,255 ⟶ 1,260:
sl_done();
return 0;
}</
{{out}}
Line 1,262 ⟶ 1,267:
=={{header|Sidef}}==
{{trans|Python}}
<
func hough(im, width=460, height=360) {
Line 1,297 ⟶ 1,302:
var img = %s|Imager|.new(file => 'Pentagon.png')
var ht = hough(img)
ht.write(file => 'Hough transform.png')</
=={{header|Tcl}}==
Line 1,307 ⟶ 1,312:
{{trans|Kotlin}}
{{libheader|DOME}}
<
import "dome" for Window, Process
import "math" for Math
Line 1,397 ⟶ 1,402:
readInputFromImage(filename) {
var inputImage = ImageData.
var width = inputImage.width
var height = inputImage.height
Line 1,443 ⟶ 1,448:
var height = Num.fromString(args[5])
var minCont = Num.fromString(args[6])
var Game = HoughTransform.new(inFile, outFile, width, height, minCont)</
{{out}}
Line 1,453 ⟶ 1,458:
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
{{trans|D}}
<
fcn houghTransform(image,hx=460,hy=360){
if(hy.isOdd) hy-=1; // hy argument must be even
Line 1,469 ⟶ 1,474:
}
out
}</
<
p:=System.popen("convert \"%s\" ppm:-".fmt(fileName),"r");
img:=PPM.readPPM(p);
Line 1,478 ⟶ 1,483:
}
houghTransform(readPNG2PPM("pentagon.png"))
.write(File("pentagon_hough.ppm","wb"));</
{{out}}
The output image looks the same as in the Go solution.
|