3d scanner code v1

scan.rb

begin
  require 'oily_png'
rescue LoadError
  STDERR.puts 'Warning: Gem oily_png not found. Using chunky_png instead. This will be slow!'
  require 'chunky_png'
end

def load_image(file)
  ChunkyPNG::Image.from_file(file)
rescue ChunkyPNG::SignatureMismatch
  `convert '#{file}' '#{file}.png'`
  img = ChunkyPNG::Image.from_file("#{file}.png").tap{File.delete "#{file}.png"}
end

def find_laser(img, opts={})
  threshold = opts[:threshold] || 127
  channel = opts[:channel] || :r
  out_img = ChunkyPNG::Image.new(img.width, img.height, ChunkyPNG::Color::BLACK)
  out_raw = []
  img.height.times.each do |y|
    max_intensity, max_intensity_pos = 0, 0
    img.width.times.each do |x|
      intensity = ChunkyPNG::Color.send(channel, img[x,y])
      if intensity > max_intensity
        max_intensity = intensity
        max_intensity_pos = x
      end
    end
    if max_intensity >= threshold
      out_img[max_intensity_pos, y] = ChunkyPNG::Color::WHITE
      out_raw << [max_intensity_pos, y]
    end
  end
  [out_img, out_raw]
end

x_range = (230..330) #rough estimation
y_range = (254..473) #rough estimation
normal_x = (x_range.min + x_range.max) / 2 #rough estimation
px_per_frame = 3 #rough estimation replace with encoder-band later maybe
laser_threshold = 127
laser_color_channel = :r


pcf = File.open('point_cloud.xyz', 'w')
depth_map = ChunkyPNG::Image.new(500, 500, ChunkyPNG::Color.rgb(127,127,127))

Dir['ginger_frames/*.jpg'].sort.each_with_index do |file, idx|
  puts file
  img = load_image(file).crop(x_range.min, y_range.min, x_range.max - x_range.min, y_range.max - y_range.min)
  laser_img, laser_raw = find_laser(img, threshold: laser_threshold, channel: laser_color_channel)
  laser_raw.each do |x,y|
    xyz = [idx * px_per_frame, y, normal_x - x].map{|e| e.round(2)}
    _z = 127 + [[xyz[2].to_i / 2, -127].max, 128].min
    depth_map[xyz[0],xyz[1]] = ChunkyPNG::Color.rgb(_z,_z,_z)
    pcf.puts xyz.join(' ')
  end
end

depth_map.save('depth_map.png')