150 lines
4.4 KiB
Lua
150 lines
4.4 KiB
Lua
local gm = require 'graphicsmagick'
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local image = require 'image'
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local iproc = {}
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local clip_eps8 = (1.0 / 255.0) * 0.5 - (1.0e-7 * (1.0 / 255.0) * 0.5)
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function iproc.crop_mod4(src)
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local w = src:size(3) % 4
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local h = src:size(2) % 4
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return iproc.crop(src, 0, 0, src:size(3) - w, src:size(2) - h)
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end
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function iproc.crop(src, w1, h1, w2, h2)
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local dest
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if src:dim() == 3 then
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dest = src[{{}, { h1 + 1, h2 }, { w1 + 1, w2 }}]:clone()
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else -- dim == 2
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dest = src[{{ h1 + 1, h2 }, { w1 + 1, w2 }}]:clone()
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end
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return dest
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end
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function iproc.crop_nocopy(src, w1, h1, w2, h2)
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local dest
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if src:dim() == 3 then
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dest = src[{{}, { h1 + 1, h2 }, { w1 + 1, w2 }}]
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else -- dim == 2
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dest = src[{{ h1 + 1, h2 }, { w1 + 1, w2 }}]
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end
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return dest
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end
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function iproc.byte2float(src)
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local conversion = false
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local dest = src
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if src:type() == "torch.ByteTensor" then
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conversion = true
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dest = src:float():div(255.0)
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end
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return dest, conversion
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end
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function iproc.float2byte(src)
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local conversion = false
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local dest = src
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if src:type() == "torch.FloatTensor" then
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conversion = true
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dest = (src + clip_eps8):mul(255.0)
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dest[torch.lt(dest, 0.0)] = 0
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dest[torch.gt(dest, 255.0)] = 255.0
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dest = dest:byte()
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end
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return dest, conversion
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end
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function iproc.scale(src, width, height, filter, blur)
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local conversion, color
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src, conversion = iproc.byte2float(src)
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filter = filter or "Box"
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if src:size(1) == 3 then
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color = "RGB"
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else
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color = "I"
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end
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local im = gm.Image(src, color, "DHW")
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im:size(math.ceil(width), math.ceil(height), filter, blur)
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local dest = im:toTensor("float", color, "DHW")
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if conversion then
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dest = iproc.float2byte(dest)
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end
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return dest
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end
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function iproc.scale_with_gamma22(src, width, height, filter, blur)
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local conversion
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src, conversion = iproc.byte2float(src)
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filter = filter or "Box"
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local im = gm.Image(src, "RGB", "DHW")
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im:gammaCorrection(1.0 / 2.2):
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size(math.ceil(width), math.ceil(height), filter, blur):
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gammaCorrection(2.2)
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local dest = im:toTensor("float", "RGB", "DHW"):clamp(0.0, 1.0)
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if conversion then
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dest = iproc.float2byte(dest)
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end
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return dest
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end
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function iproc.padding(img, w1, w2, h1, h2)
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local dst_height = img:size(2) + h1 + h2
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local dst_width = img:size(3) + w1 + w2
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local flow = torch.Tensor(2, dst_height, dst_width)
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flow[1] = torch.ger(torch.linspace(0, dst_height -1, dst_height), torch.ones(dst_width))
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flow[2] = torch.ger(torch.ones(dst_height), torch.linspace(0, dst_width - 1, dst_width))
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flow[1]:add(-h1)
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flow[2]:add(-w1)
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return image.warp(img, flow, "simple", false, "clamp")
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end
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function iproc.zero_padding(img, w1, w2, h1, h2)
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local dst_height = img:size(2) + h1 + h2
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local dst_width = img:size(3) + w1 + w2
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local flow = torch.Tensor(2, dst_height, dst_width)
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flow[1] = torch.ger(torch.linspace(0, dst_height -1, dst_height), torch.ones(dst_width))
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flow[2] = torch.ger(torch.ones(dst_height), torch.linspace(0, dst_width - 1, dst_width))
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flow[1]:add(-h1)
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flow[2]:add(-w1)
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return image.warp(img, flow, "simple", false, "pad", 0)
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end
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function iproc.white_noise(src, std, rgb_weights, gamma)
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gamma = gamma or 0.454545
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local conversion
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src, conversion = iproc.byte2float(src)
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std = std or 0.01
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local noise = torch.Tensor():resizeAs(src):normal(0, std)
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if rgb_weights then
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noise[1]:mul(rgb_weights[1])
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noise[2]:mul(rgb_weights[2])
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noise[3]:mul(rgb_weights[3])
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end
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local dest
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if gamma ~= 0 then
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dest = src:clone():pow(gamma):add(noise)
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dest[torch.lt(dest, 0.0)] = 0.0
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dest[torch.gt(dest, 1.0)] = 1.0
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dest:pow(1.0 / gamma)
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else
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dest = src + noise
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end
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if conversion then
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dest = iproc.float2byte(dest)
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end
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return dest
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end
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local function test_conversion()
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local a = torch.linspace(0, 255, 256):float():div(255.0)
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local b = iproc.float2byte(a)
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local c = iproc.byte2float(a)
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local d = torch.linspace(0, 255, 256)
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assert((a - c):abs():sum() == 0)
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assert((d:float() - b:float()):abs():sum() == 0)
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a = torch.FloatTensor({256.0, 255.0, 254.999}):div(255.0)
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b = iproc.float2byte(a)
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assert(b:float():sum() == 255.0 * 3)
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a = torch.FloatTensor({254.0, 254.499, 253.50001}):div(255.0)
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b = iproc.float2byte(a)
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print(b)
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assert(b:float():sum() == 254.0 * 3)
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end
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--test_conversion()
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return iproc
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