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ISIS Documentation

mode

Set pixels to mode of surrounding pixel values

This program accepts a user-defined boxcar and loops through the input image. It finds the mode pixel value in the boxcar, and sets the center pixel value to that mode value. If the boxcar is poly-modal, the filter writes the lowest of the mode values to the center

Categories

History

Brendan George2005-11-21 Original version
Brendan George2006-06-06 Added Minopt parameter, modified user interface.
Brendan George2006-06-19 Modified user interface

Parameters

Files

This is the cube from which we will gather our data.
Type cube
File Mode input
Filter *.cub

This is the cube to which we will write the modified data.
Type cube
File Mode output
Filter *.cub

Boxcar Size

This will determine how many samples the boxcar will have. The number must be an odd integer, and size often has a noticeable impact on time. It will also have an impact on the blurring effect. The larger the boxcar, the greater the blurring. The user will have to discover other effects on their own.
Type integer
Minimum 1 (inclusive)
Odd This value must be an odd number

This will determine how many lines the boxcar will have. The number must be an odd integer, and size often has a noticeable impact on time. It will also have an impact on the blurring effect. The larger the boxcar, the greater the blurring. The user will have to discover other effects on their own.
Type integer
Minimum 1 (inclusive)
Odd This value must be an odd number

Boxcar Settings

This value indicates the minimum value of a valid pixel. If a pixel holds a value below the minimum value, it will either be excluded or included, depending on user input in the "Filter Style" area.
Type double
Internal Default Use all
Less Than HIGH

This value indicates the maximum value of a valid pixel. If a pixel holds a value over the maximum value, it will either be excluded or included, depending on user input in the "Filter Style" area.
Type double
Internal Default Use all
Greater Than LOW

This parameter determines whether the minimum parameter is to be interpreted as a count of pixels, or a percentage of all pixels in the boxcar.
Type string
Default COUNT
Option List:
Option Brief Description
COUNT Minimum valid pixel count This option indicates that the minimum is a minimum count of pixels required for filtering.
PERCENTAGE Minimum valid pixel percentage This option indicates the the minimum parameter is to be interpreted as a percentage of the total pixels in the boxcar.

This option is the minimum number of valid pixels required in a boxcar for filtering to begin.
Type double
Default 1

This determines what to put in the center pixel, in the event that there aren't enough non-special pixels in the boxcar to meet the minimum. The default is to replace it with the current value, and the other option is to replace it with NULL.
Type string
Default CENTER
Option List:
Option Brief Description
CENTER Center pixel value This sets the center pixel of the boxcar to whatever was already there, in the event that there are not enough non-Special pixels to meet minimum requirements.
NULL Pixel value Null This sets the center pixel of the boxcar to the special pixel value fo "Null", if there are not enough non-Special pixels to meet minimum requirements.

Non-Special Pixel Filtering

These options determine which pixels are to be included in the filtering process. ALL filters all pixels, regardless of value, VALID only filters those pixels with values between LOW and HIGH, and INVALID only filters those pixels with values outside LOW and HIGH. Note that these only determine which Non-Special pixels to filter. Also, the median will only be calculated from pixel values between LOW and HIGH.
Type string
Default ALL
Option List:
Option Brief Description
ALL Filter All This option filters all Non-Special pixels, regardless of value. It only filters Special Pixels indicated by the user, and the mode value is only calculated from values between LOW and HIGH.
INSIDE Filter Between Low and High This option filters only those pixels whose value lies between LOW and HIGH, as well as the Special Pixels indicated by the user.
OUTSIDE Filter Outside Low and High This option will filter only those pixels with values below LOW or above HIGH. It will filter any Special Pixels indicated by the user, and the mode value is still calculated from between LOW and HIGH.

Valid Pixel Definition

If the center of the boxcar is Null, and this box is checked, the pixel will be overwritten with the mode value of the boxcar as a whole. If this box is left unchecked, the pixel will be left alone.
Type boolean
Default TRUE

If the center of the boxcar is Hrs, and this box is checked, the pixel will be overwritten with the mode value of the boxcar as a whole. If this box is left unchecked, the pixel will be left alone.
Type boolean
Default TRUE

If the center of the boxcar is His, and this box is checked, the pixel will be overwritten with the mode value of the boxcar as a whole. If this box is left unchecked, the pixel will be left alone.
Type boolean
Default TRUE

If the center of the boxcar is Lrs, and this box is checked, the pixel will be overwritten with the mode value of the boxcar as a whole. If this box is left unchecked, the pixel will be left alone.
Type boolean
Default TRUE

If the center of the boxcar is Lis, and this box is checked, the pixel will be overwritten with the mode value of the boxcar as a whole. If this box is left unchecked, the pixel will be left alone.
Type boolean
Default TRUE

Example 1

Running mode with a 3x3 boxcar

This demonstrates running the mode program on a sample cube.

Command Line

This demonstrates the commands necessary to run mode on a file named "peaks.cub" with a 3x3 boxcar. The small size will not produce much difference.
mode from= peaks.cub to=3x3mode.cub samples=3 lines=3

GUI Screenshot

mode gui

Example GUI

mode gui

Screenshot of the GUI set to filter all pixels for the image using a 3x3 boxcar.

Input Image

input cube

Input image before mode filter

input cube

Parameter Name: FROM

This is the original cube. The areas of greatest interest are those with a great deal of contrast such as edges.

Output Image

mode output

Output of 3x3 boxcar mode filter

mode output

Parameter Name: TO

This is the image after the filter. You may notice that the whole image is slightly softer, particularly around areas of sharp contrast. Due to the small size of the boxcar, the effect is subtle and difficult to notice.

Example 2

Running mode with a 15x15 boxcar

This demonstrates running the mode program on a sample cube.

Command Line

This demonstrates the commands necessary to run mode on a file named "peaks.cub" with a 15x15 boxcar. The large size of the boxcar produces a marked effect.
mode from= peaks.cub to=15x15mode.cub samples=15 lines=15

GUI Screenshot

mode gui

Example GUI

mode gui

Screenshot of the GUI set to filter all pixels for the image using a 15x15 boxcar.

Input Image

input cube

Input image before mode filter

input cube

Parameter Name: FROM

This is the original cube. The areas of greatest interest are those with a great deal of contrast such as edges.

Output Image

mode output

Output of 15x15 boxcar mode filter

mode output

Parameter Name: TO

This is the output image for a 15x15 boxcar. You will notice the entire image is noticeably blurrier. It is now virtually impossible to make out any but the largest of features.