Victor Image Processing Library How-to Tips

Combine Images

addimage
addtexture
andimage
bleachimage
copyimage
cover
coverclear
darker
difference
differenceabs
divideimage
isolate
lighter
multiplyimage
multnegimage
orimage
subimage
wtaverage
xorimage

Source

Operator

Result

The Victor Library provides many ways that images can be combined. These examples are all using grayscale images where black pixels have the value zero and white pixels have the value 255. If a computed result pixel value is greater than 255 it is set to 255. If a result value is less than zero it is set to zero.

These functions operate on 8-bit grayscale and 24-bit RGB color images. The bitwise AND, OR, and XOR functions also operate on 1-bit black and white images.

Function Operation Description

addimage Result = Source + Operator Add two images

addtexture Result = Source + Operator - 128 Put a texture onto an image

andimage Result = Source AND Operator Bitwise AND two images

bleachimage Result = (255-Source) * (255-Operator) / 255 Unusual effect

copyimage Result = Source Place side-by-side, top-to-bottom, or copy to any position

cover if Operator > threshold then
Result = Operator
if Operator <= threshold then
Result = Source
Overlay two images, transparent range of colors

coverclear if Operator = transcolor then
Result = Source
else
Result = Operator
Overlay two images, transparent color

darker if Source < Operator then
Result = Source
else
Result = Operator
Darker pixels of each image

difference Result = Source - Operator + 128 Positive difference is bright, negative difference is dark

differenceabs Result = | Source - Operator| Absolute value of the difference

divideimage Result = Source / Operator Divide one image by the other

isolate Result = (Source + Operator) Operator is black area to isolate and white elsewhere

lighter if Source > Operator then
Result = Source
else
Result = Operator
Lighter pixels of each image

multiplyimage Result = Source * Operator / 255 Multiply two images

multnegimage Result = 255 - ((255-Source) * (255-Operator) / 255) Unusual effect

orimage Result = Source OR Operator Bitwise OR two images

subimage Result = Source - Operator Subtract two images

wtaverage Result = (weight * Source + (100 - weight) * Operator) / 100 Weighted average of two images

xorimage Result = Source XOR Operator Bitwise XOR two images

correlationcoef Calculate the correlation coefficient between two images as a double precision floating point number

correlateimages Calculate the correlation coefficient between the Operator image and the Source image at every pixel position in the Source image and places the scaled coefficient data in the Result image.

Victor Image Processing Library homepage | Victor Product Summary | more Source code

Function	Operation	Description
addimage	Result = Source + Operator	Add two images
addtexture	Result = Source + Operator - 128	Put a texture onto an image
andimage	Result = Source AND Operator	Bitwise AND two images
bleachimage	Result = (255-Source) * (255-Operator) / 255	Unusual effect
copyimage	Result = Source	Place side-by-side, top-to-bottom, or copy to any position
cover	if Operator > threshold then Result = Operator if Operator <= threshold then Result = Source	Overlay two images, transparent range of colors
coverclear	if Operator = transcolor then Result = Source else Result = Operator	Overlay two images, transparent color
darker	if Source < Operator then Result = Source else Result = Operator	Darker pixels of each image
difference	Result = Source - Operator + 128	Positive difference is bright, negative difference is dark
differenceabs	Result = \| Source - Operator\|	Absolute value of the difference
divideimage	Result = Source / Operator	Divide one image by the other
isolate	Result = (Source + Operator)	Operator is black area to isolate and white elsewhere
lighter	if Source > Operator then Result = Source else Result = Operator	Lighter pixels of each image
multiplyimage	Result = Source * Operator / 255	Multiply two images
multnegimage	Result = 255 - ((255-Source) * (255-Operator) / 255)	Unusual effect
orimage	Result = Source OR Operator	Bitwise OR two images
subimage	Result = Source - Operator	Subtract two images
wtaverage	Result = (weight * Source + (100 - weight) * Operator) / 100	Weighted average of two images
xorimage	Result = Source XOR Operator	Bitwise XOR two images
correlationcoef	Calculate the correlation coefficient between two images as a double precision floating point number
correlateimages	Calculate the correlation coefficient between the Operator image and the Source image at every pixel position in the Source image and places the scaled coefficient data in the Result image.