Grid Pictures Modification
Geometrical Modifications Clip – Rectangular – Other shapes Rotate – Left, Right – 180 degrees – Flip
warping
Morphing
Resolution modification Resolution / number of pixels /dimensions of picture Resolution Decreasing (average color of pixels) Resolution increasing - copying of pixels - dithering
Color depth decreasing Rounding of colors Establishing of color palette Half toning Dithering
Half Toning Half tone matrix – example
Floyd Steinberg dithering 7/16 3/165/16 1/16
Pixel color correction Color correction Saturation correction Brightness correction – Simple brightness correction – Contrast correction – Gamma correction
Saturation S
Saturation correction S
Brightness Light
Brightness histogramm K W
Color brightness Y = 0,299R + 0,587G B
Simple brightness correction Original br New br
Simple brightness decreasing Original br New br
Contrast decreasing Original br New br
Contrast increasing Original br New br
Gamma correction of brightness Original br New br
Gamma function Tedy Y = 255 * (x/255) 1/γ Y = x 1/γ Y = y min + (y max -y min )*(x/x max ) 1/γ
Gamma correction Original bright nessOn γ=0,5γ=2, , , , , , , , , , , , , ,117650, , , , ,250980, , , , ,86270, ,