show.image {adimpro}

I/O functions

Description

Display an image on the screen.

Usage

show.image(img, max.x = 1000, max.y = 1000, gammatype = "ITU", 
           whitep = NULL, temp = NULL, cspace = "sRGB", black=0, exposure = 1, 
           channel=NULL, new = FALSE,  ...)

Arguments

img

image data, an object of class "adimpro".

max.x

maximum value of pixels in x dimension to be displayed.

max.y

maximum value of pixels in y dimension to be displayed.

gammatype

character, determines the type of gamma correction within the image. "ITU" stands for ITU-R BT.709-3 as e.g. used by dcraw. Alternatives recognized within the package are "None", "sRGB" and "CIE" (CIE L*). gammatype="histogram" forces histogram equalization based on the corresponding greyvalue image.

cspace

defines the output color space, default "sRGB" (sRGB D65), alternatives are "Adobe" (Adobe 1998 D65), "wGamut" (Wide Gamut D65), "kodak" (Kodak ProPhoto D65) "xyz", "yuv", "yiq" and "hsi". NULL keeps the actual setting. If color.space%in%c("hsi","yuv","yiq","xyz") the individual channels are rescaled to provide maximum contrast. Information from the three channels is coded as "red", "green" and "blue" providing a miscolored image in these cases. Individual channels can be displayed as greyvalue images by specifying the channel argument. color.space="greyvalue" provides a greyvalue image.

whitep

White point in xyY space. Can be given as one of (character) c("A","B","C","E","D50","D55","D65","D75","F2","F7","F11") or as a two element numeric vector of chromatic xy coordinates. "D65" corresponds to the default white point of "sRGB" and "Adobe" RGB-spaces. NULL keeps the actual setting.

temp

Color temperature. Can be used to specify chromatic xy coordinates of the whitepoint. Only used if is.null(whitep).

black

Adjustment for black color. Color values with luminance <= black will be assigned to black in RGB. Adjustment ist done in xyY space.

exposure

Multiplicative factor for all color channels (in xyz or rgb spaces). Applied in linear color space, i.e. if the image is gamma corrected the gamma correction is reversed first.

channel

allows to select a color channel (1: red, 2: green, 3: blue in case of "rgb") for display.

new

should new X11() be opened? default FALSE

...

additional arguments to image can be passed here.

Details

This function displayes greyscale and color images on the screen. If the actual dimension of the image exceeds max.x or max.y the image is shrinked by displaying only part of the pixels (every second/third/... such that the resulting dimension is smaller than max.x or max.y)

Value

Nothing is returned

Author(s)

Karsten Tabelow [e-mail] and Joerg Polzehl [e-mail]

See Also

read.image, write.image, adjust.image

Examples

## Not run: demo(io)