Merge pull request #76 from krasin/two-args-png-load

png: add support for 16-bit PNG files.

5 files changed, 49 insertions, 0 deletions

diff --git a/test/gray16-1x2.png b/test/gray16-1x2.png
new file mode 100644
index 0000000..9b3cb5e
--- /dev/null
+++ b/test/gray16-1x2.png
diff --git a/test/gray3x1.png b/test/gray3x1.png
new file mode 100644
index 0000000..ce89719
--- /dev/null
+++ b/test/gray3x1.png
diff --git a/test/rgb16-2x1.png b/test/rgb16-2x1.png
new file mode 100644
index 0000000..3aab682
--- /dev/null
+++ b/test/rgb16-2x1.png
diff --git a/test/rgb2x1.png b/test/rgb2x1.png
new file mode 100644
index 0000000..60a0e9f
--- /dev/null
+++ b/test/rgb2x1.png
diff --git a/test/test_png.lua b/test/test_png.lua
new file mode 100644
index 0000000..c01915d
--- /dev/null
+++ b/test/test_png.lua
@@ -0,0 +1,49 @@
+require 'image'
+
+-- Create an instance of the test framework
+local mytester = torch.Tester()
+local precision_mean = 1e-3
+local test = {}
+
+function checkPNG(imfile, depth, tensortype, want)
+  local img = image.load(imfile, depth, tensortype)
+  -- Tensors have to be converted to double, since assertTensorEq does not support ByteTensor
+  print('img: ', img)
+  print('want: ', want)
+  mytester:assertTensorEq(img:double(), want:double(), precision_mean,
+                          string.format('%s: pixel values are unexpected', imfile))
+end
+
+function test.LoadPNG()
+  -- Gray 8-bit PNG image with width = 3, height = 1
+  local gray8byte = torch.ByteTensor({{{0,127,255}}})
+  checkPNG('gray3x1.png', 1, 'byte', gray8byte)
+
+  local gray8double = torch.DoubleTensor({{{0, 127/255, 1}}})
+  checkPNG('gray3x1.png', 1, 'double', gray8double)
+
+  -- Gray 16-bit PNG image with width=1, height = 2
+  local gray16byte = torch.ByteTensor({{{0, 255}}})
+  checkPNG('gray16-1x2.png', 1, 'byte', gray16byte)
+
+  local gray16float = torch.FloatTensor({{{0, 65534/65535}}})
+  checkPNG('gray16-1x2.png', 1, 'float', gray16float)
+
+  -- Color 8-bit PNG image with width = 2, height = 1
+  local rgb8byte = torch.ByteTensor({{{255, 0, 0, 127, 63, 0}}})
+  checkPNG('rgb2x1.png', 3, 'byte', rgb8byte)
+
+  local rgb8float = torch.FloatTensor({{{1, 0, 0, 127/255, 63/255, 0}}})
+  checkPNG('rgb2x1.png', 3, 'float', rgb8float)
+
+  -- Color 16-bit PNG image with width = 2, height = 1
+  local rgb16byte = torch.ByteTensor({{{255, 0, 0, 127, 63, 0}}})
+  checkPNG('rgb16-2x1.png', 3, 'byte', rgb16byte)
+
+  local rgb16float = torch.FloatTensor({{{1, 0, 0, 32767/65535, 16383/65535, 0}}})
+  checkPNG('rgb16-2x1.png', 3, 'float', rgb16float)
+end
+
+-- Now run the test above
+mytester:add(test)
+mytester:run()