augment.lua

-- Author: Sangpil Kim and Aysegul Dundar
-- Date:   May, 2016 ~ December, 2014
require 'image'
require 'trepl'
require 'paths'

function hflip_img(dst, img, ext)

   local img_flip = image.hflip(img)
   -- assumes .png ending for now
   local img_path = string.sub(dst, 1, -5) .. "hflip"..ext
   image.save(img_path, img_flip)

end
function vflip_img(dst, img, ext)

   local img_flip = image.vflip(img)
   -- assumes .png ending for now
   local img_path = string.sub(dst,1, -5) .. "vflip"..ext
   image.save(img_path, img_flip)

end
function rotate_img(flip, dst, degree, img, ext)

   local img_rotate = image.rotate(img, degree,'bilinear')
   -- assumes .png ending for now
   local img_path = string.sub(dst,1, -5)  ..  "rotate" .. tostring(degree*10) .. ext
   image.save(img_path, img_rotate)
   if flip == true then
      hflip_img(img_path,img_rotate,ext)
   end

end
function crop5_img(flip, dst ,img , max_trans, transImgInt, ext)

   local w = img:size(2) - max_trans
   local h = img:size(3) - max_trans

   -- assumes .png ending for now
   local number_img = max_trans/transImgInt

   for i=1, number_img do
      for j=1, number_img do
         local sample = img[{{}, {1+ (j-1) * transImgInt, (j-1) * transImgInt + w},
                               {1+ (i-1) * transImgInt, (i-1) * transImgInt + h}}]

         local img_path = string.sub(dst,1,-5) .. "crop" .. (j+(i-1)*number_img) .. ext
         image.save(img_path, sample)

         if flip == true then
            hflip_img(img_path,sample,ext)
         end
      end
   end

end
function blend(img1, img2, alpha)

   return img1:mul(alpha):add(1 - alpha, img2)

end
function grayscale(dst, img, ext)

   img[2]:copy(img[1])
   img[3]:copy(img[1])
   if dst then
      local img_path = string.sub(dst,1,-5) .. "gray"  .. ext
      image.save(img_path, img)
   end

end
function gray(img)
   if img:dim() == 3 then
      img[2]:copy(img[1])
      img[3]:copy(img[1])
   end
   return img

end
function Saturation(sat, dst, img, ext)

	img[1]:add(sat)
	img[2]:add(sat)
	img[3]:add(sat)
	local img_path = string.sub(dst,1,-5) .. "sat" .. sat .. ext
	image.save(img_path, img)

end
function Contrast(con,dst,img,ext)

   gs = img:clone()
   gs = gray(gs)
   gs:fill(gs[1]:mean())
	local alpha = 1.0 + torch.uniform(-con, con)
	sample = blend(img, gs, alpha)
	local img_path = string.sub(dst,1,-5) .. "cont" .. con .. ext
	image.save(img_path, sample)

end
function ColorJitter(r, g, b, dst, img, ext)

   local ext = '.png'
	img[1]:add(r)
	img[2]:add(g)
	img[3]:add(b)
	local img_path = string.sub(dst,1,-5) .. "color".. ext
	image.save(img_path, img)

end