The merge button, found in the destination toolbar, opens up a dialog box which provides several options for merging on a pixel by pixel basis.
A dialog box above appears when merging two source pictures to the destination picture. One of several choices of merge criteria can be selected by pressing one of the ‘radio’ buttons. Some of them are self explanatory, others are not, for example ‘Greatest Pixel’ which means that on a pixel by pixel basis the destination will be the brightest value of either source 1 or source 2 for each of the red, green and blue components. The same sort of reasoning applies to Average and Least Pixel.
Subtraction of 1 from 2 and 2 from 1 means the subtraction of source 1/2 from 2/1 on a pixel-by-pixel basis with the result again transferred to the destination.The options:
are pixel by pixel switches where the color of the source 1 pixel is compared to the reference color. The first option will copy pixel 1 to the destination if that source 1 pixel is greater than the reference color otherwise it will copy the pixel from source 2.
The 2nd option is similar except the source copying is swapped.
At the bottom of the box there is a slider control that affects the weighting between the two sources for the above merging process.
There is an option on the right-hand-side of the dialog to enable infinite contrast for black and white or rgb (red,green,blue). In this case the threshold of infinite contrast switching can be set by a slider control. The default here is for normal contrast. (Infinite contrast means black or white - no gray)
You can view the destination window at the same time whilst activating the buttons and sliders to see the effect. The merge method you select remains active until you next open this dialog box.
So you want to merge more than two pictures ???
Yes you can by merging the first two to the destination, copy the destination back to one of the sources. Load the third picture as the other source and merge again. etc.
Be aware that the first two have a weighting 25% each on the final picture and the third has a weighting of 50%. However in the merge dialog box there is a slider for adjusting the bias between the two sources when merging and you could tip the balance such that it favors earlier pictures merged.Home