This tool lets you extract the foreground from the active layer or from a selection. With GIMP-2.10, selection refinement has been improved. After the selection is made, with its marching ants, you can copy-paste or click-and-drag it to another image used as background,and, inverting the selection, you can can make changes in background.
「前景抽出選択」ツールを呼びだす方法は 2 通りあります。
ツールボックスのツールアイコン
画像ウィンドウのメニューより
→ →キーボードショートカットはありません。 しかし 設定 ダイアログの「ユーザーインターフェース」のページで ボタンをクリックして「キーボードショートカット設定」ダイアログを呼びだし → と進めば、 任意にキーを設定できます。
Let us start with an object distinctly different from background, not needing to be refined.
切り出したい 前景を大まかに選択 します。 このツールを起用するとポインターの姿はなげなわツールのアイコンになります。 そのはたらきはファジー選択ツールそのものです。 背景はなるべく入らないようにします。
When the mouse pointer comes over line beginning, a small yellow circle appears: release mouse button to close selection. While selecting, click-and-drag draws a fuzzy line, drag only draws a straight line.
The selection is closed.
As soon you click to start drawing, a small window pops up:
There you have:
A Preview checkbox that toggles displaying a preview of the foreground extraction status. Esc key also toggles this preview.
A little cross to quit: returns to the original image.
A
button: not active for the moment.
Press Enter to create the mask:
The mouse pointer goes now with the Paint-brush icon. The dark blue area (this color can be changed) is for background. The light blue area covers the zone you have selected, on which you will paint to extract foreground. Between foreground area and background is a zone you have selected belonging to background named Unknown pixels area.
前景内部に線を這わせます: 描画ブラシを用い (ブラシの大きさはオプションで変更可能)、 前景の残しておきたい色のある部分を通るように一筆書きで線を描きます。 線の色には意味が無いので何色でも構いません。 前景と異なる色を使うと作業しやすいでしょう。 背景の画素 (ピクセル) を通って塗ってしまわないように気を付けましょう。
With this one-color object distinctly different from background, a few strokes are enough:
Toggle preview to verify result.
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注記 |
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This Preview mask is a mask: you can draw directly on it and see result immediately. |
Try Matting Levin engine that may improve result.
When you are satisfied with result, click on
button to get the selection of the foreground with its marching ants.一般的にはこのツールを起用すると、 そのツールオプションがツールボックスの下に繋げられたウィンドウ上に現れます。 そのようなウィンドウが見あたらないときは、 画像ウィンドウのメニューより
→ → と辿れば今使っているツールのツールオプションウィンドウが開きます。
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注記 |
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選択ツールに共通して使えるオプションについては 選択ツール をお読みください。 ここではこのツールに特有のオプションについてのみ取り上げます。 |
Draw foreground: to draw what will be foreground.
Draw background: to draw what will be background.
Draw unknown: to add to your selection pixels that are in background.
The size of the brush.
You can adapt the color of the preview to your image.
Work with Matting global(default) and improve result with Matting Levin.
Default is 1. Repeating algorithm may improve result.
In most images, foreground is not distinctly different from background. Refining selection allows you now to extract these foregrounds. Procedure steps are the same as above, but, during drawing foreground, you will often toggle Preview, use Zoom (+ key), Draw background to delete unwanted background extraction areas. You can also work directly on Preview mask.
図14.36 Example for Draw background
On the left: drawing foreground ill-advisedly went over unknown pixels area: a part of background will be included in foreground selection!
In middle: Draw background option is checked: draw on inclusion and unwanted pixels.
On the right: unwanted selected pixels in background are no longer in foreground selection.
You will often have to reduce the unknown pixels zone with Draw background.
図14.37 Example for Draw unknown
On the left: the selection left a small part of foreground unselected, in unknown pixels area.
On the right: with Draw unknown option checked, draw on unselected pixels. They are now selected in foreground.