Image Dissolving in C#
What is Image Dissolving? Basic DETAILS...
Image dissolving is based on Alpha Blending. Lets
have a look on Alpha Blending first.
Alpha blending
is a convex combination of two colors allowing for transparency effects in
computer graphics. The value of
alpha in the
color code ranges from 0.0 to 1.0, where 0.0 represents a fully transparent
color, and 1.0 represents a fully opaque color.
The value of the resulting color when color
Value1
is drawn over a background of color Value0
is given by:
-
Value = Image1(1.0 − alpha) + Image2(alpha)
The alpha component is used to blend to red,
green and blue components equally, as in 32-bit RGBA, or, alternatively, there
are three alpha values specified corresponding to each of the primary colors for
spectral color filtering.
Alpha blending is the process of combining a
translucent foreground color with a background color, thereby producing a new
blended color. The degree of the foreground color's translucency may range from
completely transparent to completely opaque. If the foreground color is
completely transparent, the blended color will be the background color.
Conversely, if it is completely opaque, the blended color will be the foreground
color. Of course, the translucency can range between these extremes, in which
case the blended color is computed as a weighted average of the foreground and
background colors. Fastgraph provides alpha blending functions that work on RGB
color values, on direct color bitmaps, and on direct color virtual buffers.
-
- In texturing, it will be used for blending color components
In RGBA texturing, the texture's alpha value is sometimes used to specify
blending
In texturing, sometimes the texture's RGB color will be used as 3 alpha
values to give spectral color filtering
Where Alpha Blending is Used:
Alpha blending can also be used for drop shadows, these are usually seen on
menus and cursors.
Basic Algorithm Of Image Averaging
Using alpha blending, one image was dissolved into
another. Essentially, the value of each pixel in the resulting image is a
weighted average of the pixels in the two originals. The weight (usually called
alpha) varies over time. This technique was applied to each of red, green, and
blue. Several output frames were generated with gradually increasing values of
alpha. Here is how it works really:
|
for(double
alpha=1.0;alpha>0.0;alpha-=(1.0/((double)(nSteps))))
{
byte*
ptr1 = ( byte*
)data1.Scan0;
byte*
ptr2 = ( byte*
)data2.Scan0;
byte*
ptr3 = ( byte*
)data3.Scan0;
for(
int i = 0 ; i <
height ; i ++ )
{
for(
int j = 0 ; j <
width * 3 ; j ++ )
{
ptr3[ 0 ] = ( byte
)(alpha*ptr1[0]+(1-alpha)*ptr2[0]);
|
Guidelines for Use
To understand the working of the
Image Averaging, take the example of the following images:
the Resultant Image
Obtained by the Averaging of the above images is as:
Sample Project
Please Review other
articles based on Logical Operators to get the better understanding of the
project. The application seems to be in this GUI.
Results:
A smooth transition from the first image to the
second is seen in the resultant image..
The project is a part of
the series of the image processing articles written just for the prosperity and
help for the students searching for Image Processing free stuff.
Attachments:
Project Files: Dissolving_Image_CSharp.zip