我正在使用JuicyPixels图像处理库来摄取图像并将其转换为矩阵类型。我想把图像的分辨率改为用户指定的维度,这样我就可以把它输入神经网络。
到目前为止,我的程序读取一张图像,并将图像转换为Data.Matrix矩阵。图像类型从 DynamicImage -> Image Pixel8 ->[[Int]] -> Matrix Int
我试着使用Haskell图像处理(HIP)库中的resize函数,但它需要并输出的类型是 Image arr cs e
我不知道如何处理。
这是我目前的代码。
import Codec.Picture
import Codec.Picture.Types
import Control.Arrow
import Data.Ratio
import Data.Monoid
import Graphics.Image.Processing
import qualified Graphics.Image as I
import qualified Data.Matrix as M
import System.FilePath.Posix (splitExtension)
-- take image input with the filepath given as a DynamicImage type
to2DMatrix :: FilePath -> String -> (Int, Int) -> IO ()
to2DMatrix fp = do
image <- readImage fp
case image of
Left _ -> putStrLn $ "Sorry, not a supported codec for " ++ fp
Right dynimg -> do
-- convert dynamic image to greyscale and then to a 2d matrix
let rle = twoDToMatrix $ pixelToInt $ greyscaleImage $ changeResolution dynimg
let (name, _) = splitExtension fp
writeFile (name ++ ".txt") (show rle)
Right _ -> putStrLn "Unhandled file type"
changeResolution :: DynamicImage -> String -> (Int, Int) -> DynamicImage
changeResolution border (dim1, dim2) img = I.resize border (dim1, dim2) img
-- convert DynamicImage to a Pixel8 image
greyscaleImage :: DynamicImage -> Image Pixel8
greyscaleImage = convertRGB8 >>> pixelMap greyscalePixel
-- convert PixelsRGB8 image to Pixel8 image
greyscalePixel :: PixelRGB8 -> Pixel8
greyscalePixel (PixelRGB8 r g b) = round (wr + wg + wb)
where wr = toRational r * (3 % 10)
wg = toRational g * (59 % 100)
wb = toRational b * (11 % 100)
-- convert Pixel8 image to a 2-d matrix of integers
pixelToInt :: Image Pixel8 -> [[Int]]
pixelToInt =
map reverse . reverse . snd . pixelFold -- because of the direction pixelFold works in, and the direction
(\(lastY, ps:pss) x y p -> -- you add things to lists, reverse and map reverse are necessary
if y == lastY -- to make the output not mirrored horizontaly and vertically
then (y, (fromIntegral p:ps):pss)
else (y, [fromIntegral p]:ps:pss))
(0,[[]])
-- converts list of lists to Data.Matrix type Matrix
twoDToMatrix :: [[Int]] -> M.Matrix Int
twoDToMatrix lists = M.fromLists lists
EDIT: 修改了程序,删除了 changeResolution
函数,因为我意识到,我可以直接使用 convert
函数或通过使用 readImageY
. 这是更新后的代码。
to2DMatrix :: FilePath -> Border(Interface.Pixel I.Y Word8) -> (Int, Int) -> IO ()
to2DMatrix fp bor (dim1, dim2)= do
eimg <- I.readImageExact VS fp
case eimg of
Left _ -> putStrLn $ "Sorry, not a supported codec for " ++ fp
Right img -> do
let imgGray :: Interface.Image VS I.Y Word8
imgGray = convert (img)
let new_res :: Interface.Image VS I.Y Word8
new_res = I.resize imgGray bor (dim1, dim2)
let rle = twoDToMatrix $ pixelToInt $ toJPImageY8 new_res
let (name, _) = splitExtension fp
writeFile (name ++ ".txt") (show rle)
我得到以下错误信息 你如何从 arr
到 VS
?
Couldn't match expected type ‘Interface.Image VS I.Y Word8’
with actual type ‘Interface.Image arr0 I.Y Word8
-> Interface.Image arr0 I.Y Word8’
• In the expression: resize imgGray bor (dim1, dim2)
In an equation for ‘new_res’:
new_res = resize imgGray bor (dim1, dim2)
In the expression:
do let imgGray :: Interface.Image VS I.Y Word8
imgGray = convert (img)
let new_res :: Interface.Image VS I.Y Word8
new_res = resize imgGray bor ...
let rle = twoDToMatrix $ pixelToInt $ toJPImageY8 new_res
let (name, _) = splitExtension fp
....
|
34 | new_res = I.resize imgGray bor (dim1, dim2)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
该 resize
功能 Haskell图像处理(HIP)中的 图书馆 用途 Image arr cs e
类型,所以我发现用HIP库读取图像比用JuicyPixels更容易。
类型从 Image VS Y Double
-> Image VS Y Word8
-> -> -> -> Pixel8
-> -> -> -> [[Int]]
->;->;->;->。Matrix Int
.
使用HIP的另一个好处是,我们可以读取灰度图像。Pixel Y
而不是以后再做转换。下面是修改后的代码。
import Codec.Picture
import Codec.Picture.Types
import Graphics.Image.Processing
import qualified Graphics.Image as I
import qualified Graphics.Image.Interface as Interface
import Graphics.Image.ColorSpace
import Data.Word (Word8)
import qualified Data.Matrix as M
to2DMatrix :: FilePath -> (Int, Int) -> IO (Maybe (M.Matrix Int))
to2DMatrix fp (dim1, dim2)= do
eimg <- I.readImageY VS fp
let new_res :: Interface.Image VS I.Y Word8
new_res = I.resize Bilinear Edge (dim1, dim2) $ Interface.map conv eimg
let rle = twoDToMatrix $ pixelToInt $ toJPImageY8 new_res
return $ Just (rle)
conv :: Interface.Pixel I.Y Double -> Interface.Pixel I.Y Word8
conv d = fmap Interface.toWord8 d
pixelToInt :: Image Pixel8 -> [[Int]]
pixelToInt =
map reverse . reverse . snd . pixelFold
(\(lastY, ps:pss) x y p ->
if y == lastY
then (y, (fromIntegral p:ps):pss)
else (y, [fromIntegral p]:ps:pss))
(0,[[]])
twoDToMatrix :: [[Int]] -> M.Matrix Int
twoDToMatrix lists = M.fromLists lists
conv
将每个像素从 Double
到 toWord8
. 图像需要有 Word8
精度 toJPImageY8
职能。