Pixel Reading
- knowing the gray level of a
specific pixel
The pixel reading allows
us to know the gray level of a specific pixel and that of its neighbors. This
function does not produce nor allows any changes on the original image.
Such analysis is useful
for works that involve the study of spectral response of targets, in various
bands of multispectral images.
SPRING presents the digital
levels of the pixels of the visualized bands. The values shown correspond to
the pixels that are present on the original image, independently from the
image visualization scale on the screen.
The pixel reading (gray
levels or colored composite) can be performed in two ways: either click in a
point on the image or place the cursor in a point of geographic, planes or
line/columns coordinates.
Reading the
gray levels of an image:
-
select an image on the "Control Panel" in Monochromatic or RGB composition;
-
click on Execute - Draw(
)
on the main menu;
-
click on image - Pixel Value... on the main menu;
-
click on View - Cross - Cursor (
)
on the main menu. By default this cursor become active when you
opened the window "Pixel Value" for the first time;
-
click on an image and you will see
a green cross over it. To cancel the cross cursor, click again on
View - Cross - Cursor. Notice that every time you click on
the image, the gray levels (GL) will be presented on the window.
NOTE: Besides the Gray Levels, the
geographic, planes and image coordinates of the chosen point will also be
presented on the window.
Reading Pixels:
-
click on Image - Pixel Values... on the main menu after having the image presented on
the drawing area;
-
click on Set Cursor Position...
or in Tools - Set Cross-Cursor Position...;
-
the Gray Levels are presented each time you press
Apply
on the "Set Cursor Position" window.
Saving the data presented on the Image
- Pixel Values... window:
-
click on Save...;
-
a SPRING window is presented and you should type in a
name
for a text file (txt) to save the data.
The list with values is
cumulative. So, if you want to clean it see the instructions below:
Removing values:
-
on the window
"Pixel Values" click on Delete
to remove the undesired data.
See also:
Read
more about Image Processing Techniques
Image Processing Menu
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