Cross referenced help
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.1
        G.I.P. Help System

@2[General]
@7[Point Processes]
@14[Area Processes]
@32[Combining Images]
@27[Windows]
@28[Icons]
@23[Menus]
@13[Image Display]
@3[Atari Series]
@4[Image Formats]
@5[SHAREWARE]

.2
          General Help
 G.I.P.  is  a  greyscale  image
processor which can be  used  to
enhance images ( for DTP use for
 example )  and  process  images
with filters.

The program runs on the @3[Atari]
range of computers and supports
a wide range of @4[image formats]

.3
    Atari Computers Supported
G.I.P will execute  on  the  Atari
ST, STE, TT and Falcon. 

On the Falcon, Multitos  is  fully
supported.

All   graphics   resolutions   are
supported. Including TRUECOLOUR on
the Falcon.

.4
         Image Formats
The following image formats can be
processed with G.I.P.

  @29[TIFF]version 5.0   (.TIF)
  Compuserve GIF      (.GIF)
  Degas               (.PI?)
  Degas Elite         (.PC?)
  PC Paintbrush       (.PCX)
  Aim Greyscale       (.IM)
  Aim Colour          (.COL)
  Monochrome GEM      (.IMG)
  Hyperpaint GEM      (.IMG)

.5
      Program Information
G.I.P is SHAREWARE.If you use this
program, please send  15 to

   Stephen Found
   14 Bybrook Court,
   Kennington,
   Ashford,
   Kent.
   ENGLAND
   TN24 9JX

   Please support SHAREWARE.
   
.6
          Area Selection
An area  of  an  image  is  easily
defined  with  the  mouse.  Simply 
place the mouse in  a  window  and
drag  the  mouse  with  the   left 
button held down.

Once  defined,  all processes will
only affect the selected area.

To delete an area,double click the
mouse in the  window.
.7
        Point processes
Point processes affect all pixels
in an @6[image area] in a uniform
way. 

G.I.P.  provides  the   following
processes.

  @8[Brightness]   @11[Contrast]
  @9[Threshold]    @12[Negation]
  @10[Histogram]
.8
        Image Brightness
This  option  allows you to add a
constant value to every  pixel in
the  image.  If  the   value   is
negative, the image  will  become 
darker.
.9
          Thresholding
This option converts a grey image
to monochrome. A value from 0-255 
is entered which is the threshold 
value. 

A pixel will become white if it's 
grey value exceeds the  threshold 
and black if not.
.10
             Histogram
A histogram of the image showing
the number of occurences of each
grey level is displayed.
.11
             Contrast
Contrasting is a  point  process
which improves the usage of the
greyscale range within @6[images]

A threshold is entered, then the
process scans the image from the
darkest and lightest  pixels  to
find the range that  exceeds the
threshold  in  both  directions.
All pixels within the resulting
range are re-mapped to 0-255.
.12
             Negation
Negation produces a 'negative'  of
@6[the image]. A threshold value  is 
requested,  then  the   image   is
negated.All pixel values above the
threshold   are   subtracted  from 
255. Thus pixels  that  were  dark
become light and vice versa.

If the entered threshold is 0, the 
resulting image will be  an  exact 
negative of the original image.
.13
           Image Display
Every image  loaded  into  GIP  is 
stored as  a  256  level greyscale
image.

How the image is displayed depends
on  your  current display mode.

     2 Colour    64 level dither
     4 Colour    64 level dither
    16 Colour    16 level grey
   256 Colour    64 level grey
  True Colour    64 level grey
.14
         Area Processes
Area processes are also  known  as
@15[Filters].  Filters  are  used  to
'bring out'  various  aspects   of
images. When selected, you will be
presented with a scrolling list of
available filters. When  a  filter
is selected, it will be applied to
the current @6[Image area].
.15
           Filters
The filters supported by  GIP  are
grouped   into    the    following
categories:

@16[High spacial]   @18[Contrast]
@17[Enhancement]    @19[Detail]
@20[Gradient]       @21[Noise removal]
@22[Edge detection]
.16
      High Spacial Filters
4 types of high spacial filter are
provided. These filters accentuate
the high frequency content  of  an
image. Areas of low frequency  are
left intact.

This has the effect of  sharpening
areas of an image where  the  grey
values fluctuate and leaving areas
of uniform greyness as they were.
.17
     Edge Ehancement Filters
5 types of edge enhancement filter
are provided. 

Edge enhancement is  usually  used
as a preliminary step  to  feature
@19[extraction],  and  is   typically 
followed by @9[thresholding].

If  overlay  is  selected,   these
filters can also sharpen images.
.18
         Contrast Filters
4  types  of  'Roberts'   contrast
filters are provided.These filters
accentuate both the high and low
frequencies of an image. 
.19
     Detail Extraction Filters
4 types  of  'Laplace'  extraction
filters are provided.These filters
differ from other edge filters  in
that they are omni-directional, so
all edges are highlighted in every
direction.

Regions  of  constant  or   linear
intensity become black and regions
of rapidly changing intensity  are
highlighted.
.20
         Gradient Filters
8 Types  of  gradient  filter  are
provided,  one  for  each  compass
direction.

Other  @17[edge enhancement]  filters
process edges in 4 directions. The
gradient filters are  conceptually
the  same   but   operate   in   8 
directions.
.21
   Noise removal - Median Filter
Median filtering uses  the  values
of surrounding  pixels  to  change
the value of a central pixel.  The
values  of  all  the  pixels   are 
sorted and the the middle (median)
value is selected. The  result  is
that any abrupt change (noise)  is
eliminated.
.22
  Edge Detection - Sobel Filter
The sobel filter is the only  non-
linear filter provided. 

A  threshold  value  is  requested
which determines the range of grey
values to be processed for edges.

An overlay option is also provided
which enables detected edges to be
overlayed on the original image.
.23
           G.I.P Menus
There are 4 menu bars in GIP. Many
menu  selections   have   keyboard
shortcuts which are shown next  to
the menu title.

The GIP menu allows access to  the
credits and GEM accessories.

The other menus are @24[File], 
@25[Options] and @26[Print].
.24
            File menu
Load  - Load an image into  memory
        A wide range of @4[formats]
        are supported.
        
Save  - Save an image  in  IMG  or
        @30[TIFF]v5.0 format.

Info  - Shows  the  size  of   the
        current image.

Help  - Where you are now.

Quit  - Exit to the GEM desktop.
.25
           Options Menu
Scale - Select  display  scale  of
        the current image
        
@10[Histogram] displays  a  Histogram
of the current image.
        
@8[Bright], @12[Negate], @9[Threshold]and
@11[Contrast] select @7[Point processes]

@15[Filter], @21[Noise] and @22[Edge Detect]
select @14[Area processes].
.26
            Print Menu
This menu allows the  printing  of
images in Laserjet, Deskjet or
Postscript formats. 

The Postscript format will  output
in encapsulated postscript.

You  may  output  to  either   the
Parallel port, Serial port  or  to
disk.
.27
             Windows
Each image will be displayed in  a
GEM window when  loaded.  The  top
window is the 'active' window  and
any processing  selected  will  be
performed on  the  image  in  that
window.

You may select an @6[image area]  to
process with the mouse.

The image in the active window can
be scrolled with the mouse or  the
keyboard ( Cursor keys ).
.28
             Icons
If the screen resolution is higher
than 320 pixels wide, an icon  bar
is displayed.

There are icons for file handling,
@7[Point processes] and @14[Filters].

All  icons  have  equivalent  menu
entries and keyboard shortcuts.

See: @23[Menus]
.29
           TIFF Support
G.I.P. Supports TIFF  Version  5.0
of the following classes :-

TIFF Class B - Bilevel images 
including 'Packbits' compression.

TIFF Class G - Greyscale
including 'LZW' compression.

TIFF Class P - Palette Colour
including 'LZW' compression.
.30
           TIFF Output
G.I.P. Outputs  TIFF 5.0  Class  G
images. You may select either TIFF
uncompressed or LZW compression.

The output is in  Motorola  format
so some PC  contemptible  programs
may  have  trouble  loading  them,
although I have tested some images
with 'Coral Photopaint'  which  is
one of the few Intel programs that
recognise the existance of another
processor. ( Inverted snobbery ! )
@31[MORE]
.31
           TIFF Output
I have tried generated TIFF images
on the Apple Macintosh (MacPaint),
Atari (TruePaint)  and  the  Amiga
(Package unknown) and they  loaded 
without problems.
.32
         Combining Images
Images and @6[image areas] can  be
combined in a variety of ways.

Hold down  either  SHIFT  key  and
press the mouse button.The current
image area will be shown as a box.

Move the box, with the mouse still
pressed,  into   the   destination
image, then let go of the button.

@33[MORE]
.33
         Combining Images
A dialogue will be shown  allowing
you to select the combination type

The following types are available:
( S=Source Image, D=Dest image )

AND  D=S AND D   OR   D=S OR D
XOR  D=S XOR D   ADD  D=D + S
SUB  D=D - S     MULT D=D * S
DIV  D=D / S     MIN  D=MIN(D,S)
MAX  D=MAX(D,S)  AVG  D=(D+S)/2
OVER D=S
.End
