Twas the Lecture Before Holiday Break

1
Twas the Lecture Before Holiday Break

• Readings
• Present
• Makefiles
• Image Array Manipulation and I/O
• Simple Widget Programs

2
Holiday Reading

• The Cuckoos Egg (Gift Quiz Material)
• References for doing homework and final project
• Gumley Chapters
• 2, 3.1-3.2,4.1-4.4 (programming)
• 7.1-7.5 (displaying images)
• 9.1-9.3 (GUI programming)
• UNIX Power Tools Chapters
• 48-51

3
netpbm.tgz

• netpbm.tgz
• This is the package that contains the entire
  PBMPLUS (also known as netpbm) and is distributed
  in a format known as
• Compressed TAR File
• or
• gzipped TAR file

4
present.tgz

• To illustrate how to process these types of
  files, there is a file called simpler file
  (present.tgz) which can be accessed via anonymous
  ftp from
• ftp ftp.cis.rit.edu

5
Anonymous ftp session login

• ftp ftp.cis.rit.edu
• Name (ftp.cis.rit.edurvrpci) anonymous
• 331 Guest login ok, send your complete e-mail
  address as password.
• Password

6
Most important ftp command

• ftpgt ?

7
ftp session change directory

• ftpgt cd people/rolo/simg726
• 250 "/people/rolo/simg726" is new cwd.
• ftpgt ls
• 200 PORT command successful.
• 150 Opening ASCII mode data connection for
  /bin/ls.
• Makefile_example.tgz
• fortran_stats.tgz
• present.tgz
• 226 Listing completed.
• 54 bytes received in 0.015 seconds (3.50
  Kbytes/s)

8
ftp file transfer type

• ftpgt ascii
• 200 Type okay.
• ftpgt binary
• 200 Type okay.

9
ftp getting a single file

• ftpgt get present.tgz
• 200 PORT command successful.
• 150 Opening ASCII mode data connection for
  present.tgz (1211 bytes).
• 226 Transfer completed.
• local present.tgz remote present.tgz
• 1219 bytes received in 0.015 seconds (80.45
  Kbytes/s)

10
Getting multiple files

• ftpgt prompt
• Interactive mode off.
• ftpgt hash
• Hash mark printing on (8192 bytes/hash mark).
• ftpgt mget .tgz
• 200 PORT command successful.
• 150 Opening ASCII mode data connection for
  Makefile_example.tgz (31544 bytes).

11
Getting out of ftp

• ftpgt quit
• 221 Goodbye.

12
Most common ftp mistake

• Sending a binary file under ASCII mode
• Result
• Characters not conforming to the ASCII character
  set are removed
• ALWAYS
• Check the size of the source file and the
  transferred file

13
Uncompressing and UnTAR

• To uncompress the file
• gunzip present.tgz
• To extract the contents of the tar file
• tar xvf present.tar
• Challenge - look at the file xmas.c and figure
  out what it does
• cd present
• more xmas.c

14
Compiling the Package

• To compile or build the package, a Makefile is
  typically present which is an automatic mechanism
  to compile all the files and place them in the
  proper locations
• make
• To run the program
• xmas

15
What is a Makefile

• A makefile is a description of how to build
  things in UNIX
• Automates the creation of stuff
• It is different from a script or batch file
• Describes the relationship of components to the
  resulting object
• Keeps track of intermediate results and their age

16
Other Makefile examples

• Makefile_example.tgz
• Fortran_stats.tgz

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Makefile_example

• Take a raw file -gt convert to pgm image
• Take pgm image -gt rotate image
• Take rotated image -gt label image
• Makefiles work on file dependencies

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Mmakefile

• more Makefile
• MyCat_labeled.pgm MyCat_rotated.pgm label.dat
• ppmlabel -x 0 -y 200 -file label.dat
  MyCat_rotated.pgm gt MyCat_labeled.pgm
• MyCat_rotated.pgm MyCat.pgm
• pnmrotate 45 MyCat.pgm gt
  MyCat_rotated.pgm
• MyCat.pgm MyCat.raw
• rawtopgm 256 256 MyCat.raw gt MyCat.pgm
• clean
• rm MyCat_labeled.pgm MyCat_rotated.pgm
  MyCat.pgm

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If a file is out of date

• If you edit a file and update it, the makefile
  will know
• Example
• Edit label.dat to some other new text
• Type make again
• Look at the image

20
Fortran_stats example

• Compile a fortran program that computes the mean
  of 1,2,3,4,5
• To compile the program
• make
• To run the program
• stats

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Fortran_stats

• more Makefile
• stats main.o sum.o mean.o
• g77 -o stats main.o sum.o mean.o
• main.o main.f
• g77 -c main.f
• sum.o sum.f
• g77 -c sum.f
• mean.o mean.f
• g77 -c mean.f
• clean
• rm .o

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Fortran_stats

• more Makefile
• FORTRAN g77
• stats main.o sum.o mean.o
• (FORTRAN) -o stats main.o sum.o mean.o
• main.o main.f
• (FORTRAN) -c main.f
• sum.o sum.f
• (FORTRAN) -c sum.f
• mean.o mean.f
• (FORTRAN) -c mean.f
• clean
• rm .o

23
Typical unreadable makefile

• more makefile
• FORTRAN g77
• OBJS main.o mean.o sum.o
• .f.o
• (FORTRAN) -c .f
• stats (OBJS)
• (FORTRAN) -o stats (OBJS)
• clean
• rm .o

24
Array Manipulation and I/O
25
Array Manipulation in IDL

• Lets create an array representing a multiband
  image
• IDLgt imagebindgen(2,3,4)
• IDLgt print,image
• 0 1
• 2 3
• 4 5

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Array Manipulation in IDL

• image continued
• 6 7
• 8 9
• 10 11
• 12 13
• 14 15
• 16 17

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Array Manipulation in IDL

• image continued
• 18 19
• 20 21
• 22 23

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Array Manipulation in IDL

• Extract the first and last band of the image
• IDLgt print,image(,,0)
• 0 1
• 2 3
• 4 5
• IDLgt print,image(,,3)
• 18 19
• 20 21
• 22 23

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Array Manipulation in IDL

• Extract the first and last band of the image
  simultaneously
• IDLgt print,image(,, 0,3 )
• 0 1
• 2 3
• 4 5
• 18 19
• 20 21
• 22 23

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Array Manipulation in IDL

• Extracting the color or spectral vector of
  the first pixel
• IDLgt print,image(0,0,)
• 0
• 6
• 12
• 18

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Array Manipulation in IDL

• Assign band 1 to band 4
• IDLgt band1image(,,0)
• IDLgt image(,,3) band1
• Shortcut
• IDLgt image(,,3)image(,,0)

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Array Manipulation in IDL

• Subsectioning parts of an image
• IDLgt print,image(01,01,)
• 0 1
• 2 3
• 6 7
• 8 9
• 12 13
• 14 15
• 0 1
• 2 3

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Array Manipulation

• where function to find indices of elements that
  meet certain criteria
• IDLgt print, where( image gt 5 and image lt 12)
• Use of other arrays to index other arrays
• IDLgt indiceswhere(image gt 5 and image lt 12)
• IDLgt image(indices)-1

34
Reading Writing Data Files in IDL
35
Reading Writing Data Files

• IDL can read many types of file formats
• Files can be categorized into two general types
• Formatted ( Readable Text Numbers, ASCII)
• Unformatted( Images)

36
Reading Writing Data Files

• The three IDL commands we can use for opening
  files are as follows
• openr (open a file for reading)
• openw (open a file for writing)
• openu (open a file for reading/writing)

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sample_data_1.dat

• 0 1
• 2 3
• 4 5
• 6 7
• 8 9
• 10 11

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Syntax for Opening Data Files

• Example command for opening a file for input
• IDLgt openr, 1, sample_data_1.dat
• The argument 1 is referred to as the logical unit
  number (also known as a file handle)
• sample_data_1.dat is the input file name

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Reading the Data

• Need to allocate the array to read in the data
• IDLgt afltarr( 12)
• OR
• IDLgt afltarr( 2, 6)
• Read in the data using the readf statement
• IDLgt readf, 1, a

40
Closing the Data File

• To close the data file you can give the following
  command
• IDLgt close, 1
• A common mistake is to try to open a file(s) that
  is already open causing the error
• OPENR File unit is already open 1.
• Execution halted at MAIN (OPENR)
• Solution
• IDLgt close, /all

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Putting it all together

• IDLgt openr, 1, sample_data_1.dat
• IDLgt a fltarr( 2,12)
• IDLgt readf, 1, a
• IDLgt close, 1
• IDLgt print, a

42
Another Way of Reading in a File

• IDLgt openr, lun, sample_data_1.dat,
• /get_lun
• IDLgt a fltarr( 2, 6 )
• IDLgt readf, lun, a
• IDLgt free_lun, lun
• IDLgt print, a

43
Yet Another Way

• IDLgt file_name sample_data_1.dat
• IDLgt a fltarr( 2, 6 )
• IDLgt openr, lun, file_name, /get_lun
• IDLgt readf, lun, a
• IDLgt free_lun, lun
• IDLgt print, a

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To Output a Formatted File

• IDLgt b bindgen( 3, 2)1042
• IDLgt openw, lun, test_output.dat,
• /get_lun
• IDLgt printf, lun, b
• IDLgt free_lun, lun

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test_output.dat

• 42 52 62
• 72 82 92

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To Output an Unformatted File

• IDLgt b bindgen( 3, 2)1042
• IDLgt openw, lun, test_output.dat,
• /get_lun
• IDLgt writeu, lun, b
• IDLgt free_lun, lun

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test_output.dat

• 4gtHR\
• Why? Because ...
• - has an ASCII value of 42 decimal
• 4 - has an ASCII value of 52 decimal
• gt - has an ASCII value of 62 decimal
• H - has an ASCII value of 72 decimal
• R - has an ASCII value of 82 decimal
• \ - has an ASCII value of 92 decimal

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test_P2_image.pgm

• P2
• 3 2
• 255
• 42 52
• 62 72
• 82 92

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test_P5_image.pgm

• P5
• 3 2
• 255
• 4gtHR\

50
Testing Out Your or Somebody Elses Image I/O
Routines

• Read in a small test image
• IDLgt aRead_P2_Image(test_input.pgm)
• Write out the small test image
• IDLgt Write_P2_Image,test_output.pgm,a
• Read in the small test image you just wrote
• IDLgt bRead_P2_Image(test_output.pgm)
• Statistics (sum, mean, etc.) must be equal
• Finally, sum_squares( a - b ) must be 0.0

51
Multiband Image Pixel Ordering

• Band Sequential
• array( column, row, band)
• array( sample, line, band)
• Band Interleaved by Line
• array( column, band, row )
• array( sample, band, line)
• Band Interleaved by Pixel
• array( band, column, row )
• array( band, sample, line )

52
Multiband Image Pixel Ordering

• Let us take the following file
• test_data.dat
• 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
  20 21 22 23
• And look at the different interleaving
  representations as a multiband image.

53
Band Sequential Example

• If we read in the test_data.dat using the array
  defined as abindgen(2,3,4), we would get
• Band 0 Band 1 Band 2 Band 3
• 0 1 6 7 12 13 18 19
• 2 3 8 9 14 15 20 21
• 4 5 10 11 16 17 22 23

54
Band Interleaved by Line

• If we read in test_data.dat using the array
  defined as abindgen(2,4,3), we would get
• Band 0 Band 1 Band 2 Band 3
• 0 1 2 3 4 5 6 7
• 8 9 10 11 12 13 14 15
• 16 17 18 19 20 21 22 23

55
Band Interleaved by Pixel

• If we read in test_data.dat using the array
  defined as abindgen(4,2,3), we would get
• Band 0 Band 1 Band 2 Band 3
• 0 4 1 5 2 6 3 7
• 8 12 9 13 10 14 11 15
• 16 20 17 21 18 22 19 23

56
Reform/Transpose Conversion

• To convert previous examples from BSQ to BIL, we
  can use the following command
• Assume a BSQ image abindgen(2,3,4)
• IDLgt b reform( a, 2, 4, 3 )
• IDLgt c transpose( b, 0, 2, 1 )
• The image c is now a BIL image

57
Reform/Transpose Conversion

• To convert previous examples from BSQ to BIP, we
  can use the following command
• Assume a BSQ image abindgen(2,3,4)
• IDLgt b reform( a, 4, 2, 3 )
• IDLgt c transpose( b, 1, 2, 0 )
• The image c is now a BIP image

58
Widget Programming
59
Widget

• What is a widget?
• It is a graphical user interface component
• Basic IDL Widget Toolkit
• Widget_Base, Widget_Button
• Widget_Draw, Widget_DropList
• Widget_Label, Widget_List
• Widget_Slider, Widget_Text

60
Widget_Base

• This widget type is used to hold other widget
  types. You can think of this as your blank
  canvas. It is also known as the parent window
  in other terms.
• To invoke a widget base, you would give the
  following commands
• IDLgt base Widget_Base()
• IDLgt Widget_Control, base, /realize

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What the IDL Commands Mean

• base Widget_Base()
• In this function call, base will contain a unique
  identifier (ID) to this specific instance of a
  blank window. The window is still described in
  memory, but not displayed
• Widget_Control, base, /realize
• This tells IDL to display the entity with the ID
  value in the variable base

62
Result of the Widget_Base

• You should see a blank window similar to the one
  below

63
Other Widget Types

• To invoke a Widget_Button
• IDLgt button1 Widget_Button( base )
• IDLgt Widget_Control, base, /realize

64
To Change the Title of a Button Widget

• IDLgtWidget_Control,button1,Set_ValueOK

65
Destroying a Widget

• IDLgt Widget_Control,button1,/destroy

66
To Destroy the Base Widget

• IDLgt Widget_Control,base,/destroy
• If there are any widgets attached to the base,
  those children widgets will also be destroyed.

67
Other Widget Examples

• IDLgt basewidget_base(column1)
• IDLgt buttonwidget_button(base)
• IDLgt labelwidget_label(base)
• IDLgt widget_control,base,/realize

68
Other Widget Examples

• IDLgt base1widget_base(column1)
• IDLgt list1widget_list(base1)
• IDLgt slider1widget_slider(base1)
• IDLgt widget_control, base1, /realize

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Adding to the Previous Example

• IDLgt base2widget_base(base1,row2)
• IDLgt button1widget_button(base2, value"First
  Button")
• IDLgt button2widget_button(base2, value"Second
  Button")
• IDLgt widget_control,base1,/realize

70
Modifying Previous Example

• IDLgt widget_control,slider1,set_value100
• IDLgt widget_control,base1,/realize
• IDLgt widget_control,button2,set_value
• "Last Button"

71
Getting Information from a Widget

• IDLgtwidget_control,button1,get_valuebutton_value
• IDLgtprint,button_value
• First Button

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Have a Safe and Happy Holiday

• Remember, friends dont let friends program drunk