Graphics.Image.IO.Histogram

Documentation

data Histogram

A single channel histogram of an image.

Constructors

Histogram

Fields

• hBins :: Vector Int

  Vector containing pixel counts. Index of a vector serves as an original pixel value.

• hName :: String

  Name of the channel that will be displayed in the legend.

• hColour :: AlphaColour Double

  Color of a plotted line.

type Histograms = [Histogram]

For now it is just a type synonym, but in the future it might become a custom data type with fields like title, width, heigth, etc.

class ChannelColour cs where

Methods

csColour :: cs -> AlphaColour Double

Get a pure colour representation of a channel.

Instances

ChannelColour YCbCrA

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: YCbCrA -> AlphaColour Double

ChannelColour YCbCr

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: YCbCr -> AlphaColour Double

ChannelColour YA

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: YA -> AlphaColour Double

ChannelColour Y

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: Y -> AlphaColour Double

ChannelColour RGBA

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: RGBA -> AlphaColour Double

ChannelColour RGB

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: RGB -> AlphaColour Double

ChannelColour HSIA

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: HSIA -> AlphaColour Double

ChannelColour HSI

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: HSI -> AlphaColour Double

ChannelColour CMYKA

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: CMYKA -> AlphaColour Double

ChannelColour CMYK

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: CMYK -> AlphaColour Double

ChannelColour X

Defined in Graphics.Image.IO.Histogram

Methods

csColour :: X -> AlphaColour Double

getHistograms :: forall arr cs e. (ChannelColour cs, MArray arr X e, Array arr X e, MArray arr cs e, Array arr cs e) => Image arr cs e -> Histograms

Create a histogram per channel with 256 bins each.

getHistogram :: MArray arr X e => Image arr X e -> Histogram

Generate a histogram with 256 bins for a single channel Gray image.

equalizeHistogram :: (ToY cs e, Array arr cs e, Array arr Y Double, Array arr X Word8, MArray arr X Word8) => Image arr cs e -> Image arr Y Double

Converts an image to Luma and performs histogram equalization.

cdf :: MArray arr X e => Image arr X e -> Vector Double

Discrete cumulative distribution function.

displayHistograms :: Histograms -> IO ()

Display image histograms using an external program. Works in a similar way as displayImage.

>>> frog <- readImageRGB VU "images/frog.jpg"
>>> displayHistograms $ getHistograms frog

writeHistograms :: FilePath -> Histograms -> IO ()

Write histograms into a PNG image file.

>>> frog <- readImageRGB VU "images/frog.jpg"
>>> writeHistograms "images/frog_histogram.svg" $ getHistograms frog