adjust.image {adimpro}R Documentation

Image Processing


Color space transformations, change of white balance and exposure, gamma correction and histogram equalization.


adjust.image(img, gammatype=NULL, cspace = NULL, whitep = NULL, 
                 temp = NULL, black=0, exposure = 1, kind = "Bradford", 
                 alg = 1, compress= TRUE)



image object, class"adimpro".


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*). NULL keeps the actual setting. gammatype="histogram" forces histogram equalization based on the corresponding greyvalue image.


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.


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.


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


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


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.


Algorithm for chromatic adaptation. Alternatives are "Bradford", "VonKries" and "XYZscaling"


determines the approximation for the gamma correction. Select 1 for fastest computation and 3 for maximum accuracy, or 2 for a compromise.


logical, determines if image data are stored in raw-format.


This function adjusts color channels and applies gamma correction (if applicable).

If color.par$red or color.par$blue or color.par$brightness differ from 1.0 the corresponding channels are multiplied with the provided values. Saturated values are set to 1.

If img$gamma==FALSE, perform gamma correction with color.par$ga and color.par$bp. alg chooses between three different computing algorithms (approximations) with increasing computation time and precision (alg is 1,2, or 3).


Adjusted image object of class "adimpro".


Karsten Tabelow and Joerg Polzehl

See Also

show.image, write.image


## Not run: demo(color)

[Package adimpro version 0.9.3 Index]