Complete guide on removing image background with InstantMask Ultimate.

January 19, 2014Leave a reply


Two window design.

InstantMask Ultimate has two internal windows – left and right. Each window has its own toolbar on top of it. The left window shows the original image. The left toolbar contains the tools for image masking – selecting the foreground of an image and separating it from background. The tools include the rectangle selection tool, red and green marker and the eraser. There is also the refresh button to calculate the mask again.
The right window shows the masked image. The isolated foreground of an image is shown on top of the selected background. The default background is transparent, but can be changed to white, any solid color or another picture. The right toolbar has several brushes for refining the mask, new background selection options, zoom buttons and collage creation features. It also has the tools for working on hair/fur like objects isolation.

Selecting the foreground of an image.

InstantMask Ultimate offers several ways of selecting the foreground of a picture. The default one is the rectangle select tool. After you open a picture, the left window contains the original image. You can draw the rectangle around the desired object with the mouse, pressing the button to start selecting the rectangle and releasing it to finish. After that, the software automatically tries guessing the boundary of a desired object.
There is another experimental alternative to that – fully automatic cutout. You can just press the refresh button after the picture is open without selecting anything. The program tries finding the most important object in the picture and isolating it. But correct result is not guaranteed.
The next two tools for foreground/background selection are red and green markers. The green one is for marking the object and the red one is for background. After the marker is released the automatic updates the mask that is shown in the right window.
There also is an eraser tool that is used to remove previously drawn markers.

Refining the mask.

To refine the mask you can use two type of brushes: Normal brush (red or green) and Precise brush(also red and green). Normal red or green brush marks the whole region of similar color around the mouse click point as foreground or background. Green brush means foreground – the object that has to be isolated, so clicking the green brush makes the whole region around the specified point visible as on the original image. Red brush means background, so the whole region becomes background (transparent, selected color or different picture). Precise green and red brushes only mask the region within the brush circle – green brush turns the circle into the foreground and red – to background.

Selecting the new background color.

Select background color button opens the color selection dialog. This dialog allows specifying the new color visually or by RGB and HSV values. Alpha channel value can be also selected so the new background can be semi or fully transparent. Zero alpha channel value means fully transparent. Transparent is also the default background.

The new background picture and collage mode.

Instead of specifying the new background color the new picture can also be selected. This means the isolated object will be placed on top of another picture. There are 3 tools for scaling and positioning two pictures relatively to each other – background zoom (in and out) and hand. Background zoom scales the background picture while the foreground is kept the same size. Hand tool lets you moving the foreground picture while the background remains on the same place.

Working on hair/fur.

The background (foreground) eraser tool simplifies removing the image background around the objects similar to hair or fur. If the background is more or less uniform, the background eraser mode is preferable, if the foreground is more uniform – foreground mode may work better. The mode is selected by the foreground checkbox. If the checkbox is not selected (default) the mode is background.
The first step is to select the sample color which will indicate the background/foreground depending on the mode. There are two ways of doing it. The first one is using the color picker tool and clicking at the correspondent part on the right picture. The average color under cursor will be selected. Another way is right-click when the background eraser tool is active – it will work the same way as color picker.
In the background mode left-clicking the image under the cursor with active background eraser tool will remove all the pixels with color, similar enough to the background sample. The similarity threshold is selected by the Intensity slider.
If the Foreground mode is selected, the pixels similar to the sample are kept and everything that differs much from the sample is removed. The similarity is again determined by the intensity threshold.
When the background eraser tool is used it is recommended to select the final background first. That way you can better select the appropriate threshold so no semi-transparent remainders from the old background are visible on the new one.