The selection tools in DIP9 are used
to select areas of an image by a number of methods and either alter, remove or
add to them. They provide control by isolating an area that can then be edited
as required. Almost any task can be applied to a selection, such as adding a
filter, changing only one color in the image or increasing brightness and
contrast.
Each tool is designed to be useful
for particular tasks.
The Marquee tool allows selection by
pre defined shapes. This tool is most useful for cropping or trimming images.
To make a selection with the marquee
tool:
On the Stack, click the object
On the toolbar, click the marquee
tool button.
If you can’t see the options palette,
click the Selection button on the workspace toolbar.
To maintain smooth edges along the
selection, select the Anti-aliased check box on the Marquee Tool options
palette.
From the drop down menu, click a
shape for the marquee selection.
To keep the shape proportionate,
select Shape proportions
Most often you will want to start a
new selection, but you can also add to the current selection, or subtract from
the current selection.
Drag the marquee pointer diagonally
across the area you want to select. A dashed line appears around the selection
you have made. Anything inside that line will be affected by any changes you
make or apply to it. To select the opposite area of the image, click Invert on
the Marquee Tool options palette.
Click Adjust Marquee and make any
adjustments to the size or shape of the marquee required. E.g. you can drag the
square to make a rectangle or rotate the shape.
Choosing feather softens the edges of
an image to a value you select. This can help a selection blend into the
original or new image.
The Freehand tool lets you choose an
area by tracing it with a mouse or pen. It is useful for irregulary shaped
objects without clearly defined edges.
To make a selection with the freehand
tool:
On the Stack, click the object
On the toolbar, click the Freehand
Tool button
If you can’t see the options palette,
click the Selection button on the workspace toolbar.
To maintain smooth edges along the
selection, select the Anti-aliased check box on the Freehand Tool options
palette.
Most often you will want to start a
new selection, but you can also add to the current selection, or subtract from
the current selection.
Zoom in on the object so your view is
clear. Choose a starting point and drag your mouse or pen around the area you
wish to select. If you keep the mouse button held down then the line will be
drawn to follow. If you click and then move the mouse and click again a straight
line will be drawn between the two points. To complete a selection return to
your starting point and click on the square. A dashed line appears around the
selection you have made. Anything inside that line will be affected by any
changes you make or apply to it. To select the opposite area of the image, click
Invert.
Unfortunately the freehand tool does
not allow for editing after the selection is drawn so if you make an error in
selecting the area you will have to restart the process.
Choosing feather softens the edges of
an image to a value you select. This can help a selection blend into the
original or new image.
The Edge finder creates a selection
by mapping the edges of an object. It is best used when the object you want to
select has clear and distinct edges.
To make a selection with the Edge
Finder tool:
On the Stack, click the object
On the toolbar, click the Edge Finder
Tool button
If you can’t see the options palette,
click the Selection button on the workspace toolbar.
To maintain smooth edges along the
selection, select the Anti-aliased check box.
The pixel edge width can be
determined by you by decreasing or increasing as desired. The width is the
number of pixels away from the pointer that the Edge Finder will try to detect
an edge.
Most often you will want to start a
new selection, but you can also add to the current selection, or subtract from
the current selection.
Zoom in on the object so your view is
clear. Choose a starting point and click around the area you wish to select. You
need to keep the edge within the boundaries of the tool. By keeping the edge in
the center you will get the best results. If you keep the mouse button held down
then the line will be drawn to follow. If you click and then move the mouse and
click again a straight line will be drawn between the two points. To complete a
selection return to your starting point and click on the square. A dashed line
appears around the selection you have made. Anything inside that line will be
affected by any changes you make or apply to it. To select the opposite area of
the image, click Invert.
You can adjust your selection by
choosing Adjust edges. You can either move the square anchor points as desired
or click on any part of the line to create a new anchor point that can then be
moved.
The Magic Wand selects areas by
color. It is useful for choosing areas of the same or similar color so you don’t
have to draw around them.
To make a selection with the Magic
Wand tool:
On the Stack, click the object
On the toolbar, click the magic Wand
Tool button
If you can’t see the options palette,
click the Selection button on the workspace toolbar.
Choose the Contiguous option if you
want to select only areas of color that are connected to each other. Deselect
the box to select all areas of that color in the image.
Choose a tolerance level where 0
selects only pixels of identical color, and 255 selects all the pixels in the
object. If the selection has includes too much or too little of the area you
want to select, enter a different value in the Tolerance box, and then make
another selection.
Most often you will want to start a
new selection, but you can also add to the current selection, or subtract from
the current selection.
To select the opposite area of the
image, click Invert.
To alter an image with any tool, the
process is the same. I am using the same image to demonstrate each process.
To apply a change to an area using
the Magic Wand Tool:
Once you have made your selection you
can make changes directly to the area by choosing almost any tool from the
Format, Touchup or Effects menus for example Touchup>Brightness and Contrast. To
apply the change choose Edit>Paste. This permanently applies the change directly
to the image.
In this image I want to brighten the
right hand bottom area where the foliage is heavily darkened. Because this area
of foliage is largely uniform in color I have chosen the Magic Wand tool. I have
increased the tolerance to capture the area and you can see the dashed lines
appear around the selection. Now I choose Touchup>Brightness and Contrast and
make my adjustments as desired. Then I select Edit>Paste to apply the change.
To trim part of an image using the
Marquee Tool
Using the original image I want to
remove an area to create a frame. With my image selected I select the Marquee
Tool. With the square shape chosen I choose a starting point and drag out my
square. The dashed lines appear around my selection but I wish to change the
square to a rectangle so I select Adjust Marquee and drag the handles to form a
rectangular shape as shown. Then I click Done on the palette and go to Edit>Cut
to delete the inside area (you can also choose Edit>Delete) and then choose
Edit>Paste. This pastes the image you have chosen to cut back in its own space.
If you don’t require the image then just delete it. You may also find that the
image, in this case the frame, is locked which is indicated by a small lock
symbol next to the image in the stack. When an image is locked it can not be
moved from its position. To Unlock the image select the image and then
Edit>Unlock.
To change part of the image using the
Edge Finder Tool:
The sky in the original image is not
as saturated as I would like so I am going to use the Edge Finder to select that
area of the photograph. I have chosen a narrow edge width because the selection
area around the tree line is very uneven. I choose a starting point at the top
left corner by clicking and move the mouse to the right top corner and click,
keeping the edge at the center of the tool. The tool automatically draws a
straight line between the two points. I repeat the process down to the tree line
and then I begin to use smaller drag and clicks as indicated by the anchor
points that appear later. Using smaller strokes allows the Edge Finder to find
the edge with more accuracy. I continue the process until I have reached my
starting point. I then chose Adjust Edges at which point the anchor points
appear. I can move these if needed to ensure the edges are captured accurately.
By zooming in you will get a clearer view. I have also feathered the edge by a
value of 2 to better blend the final result. Then I have chosen TouchUp > Hue
and saturation and made my changes.
<p by then selecting edit
I could also choose Edit >Copy and
then Edit>Paste. This would alter my image but also give me a copy of just the
sky area that could be used elsewhere.
To copy part of the image using the
Freehand Tool:
From the original photograph I want a
section in the bottom left corner of a yellow flowering bush. To extract it I
select the Freehand Tool and zoom in to that area. The Edge Finder would
struggle with this task as the edges are indistinct and the area is heavily
textured. Choosing a starting point I drag the tool around the edges of the area
that I want to keep. The line will follow any moves you make with the mouse or
pen so work slowly. If you make an error you cannot adjust the line at any point
so you will have to start again (to start again move to the start point and
click and then reposition the point and begin again).
To copy the area choose Edit>Copy you
can then paste the selection onto a new canvas or where desired.
Tips for using the Selection Tools
* To make changes to a specific area
without affecting the original image make your selection then choose Edit>Copy
then Edit>Paste and you can work on that selection as a new layer in the stack.
* The Edit>Undo command works to an
extent with selections
* If you get the message “There are
no pixels in the current selection …etc” you can simply click on the correct
picture in the stack and then keep working.
* If you choose a selection tool and
then change your mind as to which tool you want to use simply select your
choice, the tool will change
* If you can’t see the options
palette, click the Selection button on the workspace toolbar.
* If you choose a selection tool and
make a selection and then decide against the action click on the object pointer
and then click anywhere on the image.
* You can cut or copy and paste
selections back onto the original image or onto a new canvas or other project.
* The Help files contains a written
and a video tutorial on using the selection tools.
* Remember never work on an original
photograph file. Always use a copy.
© Copyright 2003-2005 by Scrapbook-Bytes; & original creator/s of tutorials/articles
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