BROKEN experimental canny and hough NOT YET WORKING.

bin/magick_canny

@@ -22,6 +22,8 @@ options.highThreshold = 7.5
 options.kernelRadius = 2.0
 options.kernelWidth = 16
 options.color = 'black'
+options.roughly = true
+options.hough = false
 options.contrastNormalized = false
 options.logger = nil
 
@@ -63,6 +65,16 @@ OptionParser.new do |opts|
     options.contrastNormalized = !!contrastNormalized
   end
 
+  # Thoroughly
+  opts.on("-u", "--thoroughly", "If set, the image will not be grayscaled before processing (requires less resources, default: false)") do |thoroughly|
+    options.roughly = !thoroughly
+  end
+
+  # Thoroughly
+  opts.on("-y", "--hough", "If set, the hough matrix will be built and an image will be rotated accordingly, default: false)") do |hough|
+    options.hough = hough
+  end
+
 
   # Verbose?
   opts.on("-v", "--verbose", "Run verbosely (default: false)") do |v|
@@ -88,3 +100,10 @@ outfile = File.basename(file).sub(/(\.\w+)$/, "-canny\\1")
 Magick::Screwdrivers::canny(file, options).write(File.join File.dirname(file), outfile) { 
   self.quality = options.quality || 90
 }
+
+if options.hough
+  houghfile = File.basename(file).sub(/(\.\w+)$/, "-hough\\1")
+  Magick::Screwdrivers::hough(file, {:roughly => options.roughly, :logger => options.logger}).write(File.join File.dirname(file), houghfile) { 
+    self.quality = options.quality || 90
+  }
+end

bin/magick_sobel

@@ -24,7 +24,7 @@ OptionParser.new do |opts|
   end
 
   # Thoroughly
-  opts.on("-r", "--roughly", "If set, the image will not be grayscaled before processing (requires less resources, default: false)") do |roughly|
+  opts.on("-u", "--roughly", "If set, the image will not be grayscaled before processing (requires less resources, default: false)") do |roughly|
     options[:roughly] = !!roughly
   end
 

lib/rmagick/screwdrivers.rb

@@ -3,6 +3,7 @@
 require "rmagick/screwdrivers/poster"
 require "rmagick/screwdrivers/collage"
 require "rmagick/screwdrivers/scale"
+require "rmagick/screwdrivers/hough"
 require "rmagick/screwdrivers/sobel"
 require "rmagick/screwdrivers/canny"
 

lib/rmagick/screwdrivers/canny.rb

@@ -1,6 +1,6 @@
 # encoding: utf-8
 
-# http:# www.tomgibara.com/computer-vision/CannyEdgeDetector.java
+# http://www.tomgibara.com/computer-vision/CannyEdgeDetector.java
 # @author Tom Gibara
 # ported from java Alexei Matyushkin
 
@@ -22,7 +22,7 @@ def self.gaussian x, sigma
 		end
 
 		def self.hypot x, y
-			return Math.hypot x, y # x.abs + y.abs
+			Math.hypot x, y # x.abs + y.abs
 		end
 
 		def self.normalizeContrast data
@@ -208,9 +208,12 @@ def self.canny file, options = OpenStruct.new
     	options.kernelWidth = 16 unless options.kernelWidth && options.kernelWidth >= 2
     	options.color ||= 'black'
     	options.contrastNormalized = !!options.contrastNormalized
+    	options.roughly = !!options.roughly
 
 		begin
 			orig = img_from_file(file)
+	        orig = orig.gaussian_blur 0, 3.0
+	        orig = orig.quantize 256, Magick::GRAYColorspace unless options.roughly
 		rescue
 			warn(options.logger, "Skipping invalid file #{file}…")
 			return nil
@@ -231,7 +234,7 @@ def self.canny file, options = OpenStruct.new
 
 		magnitude = Canny::computeGradients options.kernelRadius, options.kernelWidth, width, height, data
 
-		data = (0...width*height).map { 0.0 }
+		data = (0...width*height).map { 0 }
 		offset = 0
 		for y in 0...height
 			for x in 0...width

lib/rmagick/screwdrivers/hough.rb

@@ -0,0 +1,108 @@
+# encoding: utf-8
+
+require 'RMagick'
+
+module Magick
+  module Screwdrivers
+    module Hough
+      def self.is_dark? px
+        px.red + px.green + px.blue < 40
+      end
+
+      def self.is_light? px
+        px.red + px.green + px.blue > 600
+      end
+    end
+
+    # based on http://jonathan-jackson.net/ruby-hough-hack.html
+    def self.hough file, options={}
+      options = {
+        :roughly       => false,
+        :logger        => nil
+      }.merge(options)
+
+      begin
+        orig = img_from_file(file)
+#        orig = orig.gaussian_blur 0, 3.0
+        orig = orig.quantize 256, Magick::GRAYColorspace unless options[:roughly]
+      rescue
+        warn(options[:logger], "Skipping invalid file #{file}…")
+        return nil
+      end
+
+      trigons = { :cos => [], :sin => [] }
+      hough = Hash.new(0)
+      (orig.rows - 1).times do |y|
+        orig.columns.times do |x|
+          if Hough::is_dark?(orig.pixel_color(x,y)) && Hough::is_light?(orig.pixel_color(x,y + 1))
+            (0..Math::PI).step(0.1).each do |theta|
+              trigons[:cos][theta] ||= Math.cos(theta)
+              trigons[:sin][theta] ||= Math.sin(theta)
+              distance = (x * trigons[:cos][theta] + y * trigons[:sin][theta]).to_i
+              hough[[theta, distance]] += 1 if distance >= 0
+            end
+          end
+        end
+      end
+
+      info options[:logger], 'Will print first 200 results:'
+      hough.sort_by { |k,v| v }.take(200).each { |v|
+        info options[:logger], v
+      }
+      at = hough.sort_by { |k,v| v }.inject(0.0) { |m,v| m + v[0][0] } / 20
+      info options[:logger],  "Average theta: #{at}"
+
+      orig.rotate at
+    end
+
+    # based on http://rosettacode.org/wiki/Hough_transform#Ruby
+    def self.hough_transform file, options={}
+      options = {
+        :roughly       => false,
+        :logger        => nil
+      }.merge(options)
+
+      begin
+        orig = img_from_file(file)
+#        orig = orig.gaussian_blur 0, 3.0
+        orig = orig.quantize 256, Magick::GRAYColorspace unless options[:roughly]
+      rescue
+        warn(options[:logger], "Skipping invalid file #{file}…")
+        return nil
+      end
+
+      mx, my = orig.columns * 0.5, orig.rows * 0.5
+      max_d = Math.sqrt(mx * mx + my * my)
+      min_d = -max_d
+      hough = Hash.new(0)
+      (0...orig.columns).each do |x|
+        warn(options[:logger], "#{x} of #{orig.columns}")
+        (0...orig.rows).each do |y|
+          if orig.pixel_color(x,y).green > 32
+            (0...180).each do |a|
+              rad = a * (Math::PI / 180.0)
+              d = (x - mx) * Math.cos(rad) + (y - my) * Math.sin(rad)
+              hough["#{a.to_i}_#{d.to_i}"] = hough["#{a.to_i}_#{d.to_i}"] + 1
+            end
+          end
+        end
+      end
+
+      max = hough.values.max
+
+      houghed = Image.new(orig.columns, orig.rows) { 
+        self.background_color = 'transparent' 
+      }
+
+      hough.each_pair do |k, v|
+        a, d = k.split('_').map(&:to_i)
+        c = (v / max) * 255
+#        c = heat.get_pixel(c,0)
+        houghed.pixel_color a, max_d + d, Pixel.new(c, c, c)
+      end
+
+      houghed
+    end
+
+  end
+end

lib/rmagick/screwdrivers/sobel.rb

@@ -16,6 +16,7 @@ def self.sobel file, options={}
 
       begin
         orig = img_from_file(file)
+#        orig = orig.gaussian_blur 0, 3.0
         orig = orig.quantize 256, Magick::GRAYColorspace unless options[:roughly]
       rescue
         warn(options[:logger], "Skipping invalid file #{file}…")