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------------------------------------------------------------------------- ####### # # ##### ##### ####### # ##### ###### # ## ## # # # # # # # # # # # # # # # # # # # # # # # # # # # # ####### # #### ####### # ####### ####### # # # # # # # # # # # # # # # # # # # # # # # # # # ####### # # # # ##### ####### ####### # # ###### ------------------------------------------------------------------------- ImageLab V2.2 Copyright 1989 by Gary Milliorn All Rights Reserved Distribution for non-commercial purposes is ok, as long as the program and accompanying files remain unchanged. ------------------------------------------------------------------------- 1.0 OVERVIEW ImageLab is a program which may be used to explore many common image processing operation, from simple averaging to Fast Fourier Transforms (FFT's). ImageLab makes use of the Amiga's blitter to perform fast operations where available. ImageLab is copyrighted, and is freely distributable for non-commercial purposes. ImageLab is: an evolving program. If you find it interesting, have suggestions, bug reports, etc. you can contact me at: mail: Gary Milliorn 5915 Shanghai Pierce Rd. Austin, Tx 78745 bix: gmill I can't promise everything, but I do endeavor to make it as good as I can. 1.1 GENERAL ** Note: This is the most unusual aspect of ImageLab (V2.2): ImageLab opens a window on the WorkBench screen, which allows access to its menus even when the picture you use is 320 or less. The menu strip is also attached to any picture you load, but it may be difficult to use on small screens, since there are so many menus. The easiest way to use ImageLab in this manner is to position the screen partially down the screen and start functions from the exposed WorkBench window. An alternate method is to position the image screen at the top, move WorkBench to front, and drag it partially down. However, application programs cannot reposition the WorkBench window, so you must do this. A this possibility is to keep both screens at the top and flip between them using the AMIGA-N and AMIGA-M key. 1.1.1 COMMON FEATURES The following applies throughout ImageLab unless otherwise specified: ImageLab uses the ESCAPE key to terminate an operation in progress. Whenever lengthy operation are being performed, the pointer changes to a small spinning clock. When this is true, you can press ESC to stop whatever it is doing; however, this may leave your picture in a partially altered state. ImageLab uses the RETURN and ENTER keys to simulate the "Ok" gadget which appears in requester windows. Similarly, the ESCAPE key siumulates the cancel gadget. Function can be applied to the entire picture, or to a selected area. To select an area, use the mouse to "draw" a selection rectangle by pressing the left mouse button at one corner and dragging it (with the button still down) to the opposite corner. To cancel an area selection in progress, press the ESCAPE key or the MENU button. All menu items which call up a requester for additional information have '...' appended to them. 1.2 REQUIREMENTS * Amiga 500..2000 * MC68000 or better. * 512K memory (the more, the better). * System V1.2 software or newer. 1.3 KNOWN LIMITATIONS ImageLab allocates some memory from the C-heap, instead of the system memory pool. This means you will probably need a large stack space to run extensive operations. If you experience problems, try setting the stack size to 25K or more. ImageLab's undo function is not very complete. ImageLab cannot take advantage of a MC68881 or MC68882, alas. 1.4 KNOWN BUGS * You cannot invoke the palette from the paint function. * Much of ImageLab is ready for V1.4: you can use fixed or proportional fonts, of any size. That is the intention. Some things don't adjust, so you will get best results if your font is 11 points or less. * ImageLab doesn't save "unknown" IFF objects, like DPPV and CRNG. 1.5 FUTURE ITEMS * Process images in HSI space. * Programmable convolution kernel sizes. * Super bitmap screens. * Multiple image screens. * Use menus on image screens exclusively. Pictures less than 640 pixels wide will be 320 * Use system memory allocation exclusively. * Better 'undo'. * ??? 1.6 MISCELLANEOUS Copyright 1989 by Gary W. Milliorn All rights reserved. Developed using Manx C 3.4 (!), 32-bit mode. ----------------------------------------------------------------------------- 2.0 INSTALLATION To install ImageLab in your system, you can use the install program to use the default installation procedure. Review the file first, and if it is acceptable to you, just enter "execute install" and it will run automatically. Otherwise, review the following paragraphs to install whatever portions you would like to have. 2.1 IMAGELAB PROGRAM The ImageLab program does not have any special requirements. By default, a directory is created on your SYS: directory, and ImageLab is placed in there. You can use the WorkBench or CLI to move it to a more suitable directory, if you like. 2.3 IMAGELAB FONTS ImageLab comes with two fonts, "tau" and "ceres". "Tau" is an 8-point font I run on my system (using the 1.3 command "FF"). The special feature of this font is the characters at positions $80 and $81 (hex), when printed sequentially, create an Amiga-style checkmark. Currently, application programs cannot specify the font used in menu titles, so it must be handled separately by specifying it as the default system font. If you don't like the appearance of "tau", you might consider changing those two characters to the checkmark, if only to help keep alive the old (better, IMHO) symbol of the Amiga. The second font is "ceres", and is a proportional, bold, 9-point font. ImageLab handles fonts of any style and size, up to a point. Using it is also strictly optional; if present, ImageLab uses it by default, or reverts to the system default font. You can also specify other fonts of your own choosing - see the startup section. Installing the fonts is strictly optional. 2.3 IMAGELAB HELP ImageLab can be provided with on-line help by storing the help file ("ImageLab.help") in the same location where the ImageLab program is stored (generally, "SYS:ImageLab/ImageLab.help"); alternately, it can be stored in the "S:" directory (ImageLab will locate it automatically). Installing the help file is strictly optional. ----------------------------------------------------------------------------- 3.0 STARTING IMAGELAB ImageLab can be run via the CLI or via WorkBench. Operation is basically identical, except that some of the defaults are changed. 3.1 CLI STARTUP When started from the CLI, the ImageLab command line has the following format: ImageLab [-d dir] [-f file] [-r ram] [-v] [-F font] [-c] [-?] the options are: -? : summarize CLI usage. -b : enable the bell. -c : enable the checkmark character. If you are using the "tau" font, or have modified your own, setting this option changes the "Project" menu title to an Amiga checkmark. -d dir : set the file directory to 'dir'. Otherwise, the default is the directory ImageLab was 'run' from. -f file : load initial image from 'file' (in the specified directory). -F font : specify font. Fonts are specified as "name/size", -i : enable icon generation. -r ram : use 'ram' as a ram disk. If not specified, ImageLab uses 'RAM:'. This is only needed by the "Save/Choose" option. -v : verbose. If set, ImageLab prints debugging info. as in "Helvetica/9". Icon creation is disabled when ImageLab is started from the CLI. To enable it, you must specify the "-i" option. 3.2 WORKBENCH STARTUP ImageLab can be started up via the WorkBench. Its icon is a tool, which allows it to receive filenames by clicking on a Project icon such as ImageLab creates, or selecting both to open "alien" files, such as those created by Deluxe Paint, DigiView, etc. The ImageLab icon accepts the tool types listed below. To set them, use the WorkBench "Info" function. BELL=ON|OFF : if ON, create bells; otherwise, do not. CHECKMARK=ON|OFF : if ON, enable the checkmark character. If you are using the "tau" font, or have modified your own, setting this option changes the "Project" menu title to an Amiga checkmark. DIRECTORY=name : set the file directory to "name" FONT=name : set the ImageLab font to "name" Fonts are specified as "name/size", ICON=ON|OFF : if ON, create icons; otherwise, do not. RAM=name : use "name" as a ram disk. If not specified, ImageLab uses "RAM:" This is only needed by the "Save/Choose" option. WINDOW=CON:0/0/100/100 : create a message window of the specified size. Mostly just for debug support. VERBOSE=ON|OFF : if ON, ImageLab writes debugging information to its WorkBench window. Do NOT use without a "WINDOW..." specification. If you had also selected a PROJECT when ImageLab was started, it tries to open that file as an IFF image file. Only one file may be specified this way, however. Icon creation is enabled when ImageLab is started from the CLI. To disable it, you must specify the "ICON=OFF" option. ----------------------------------------------------------------------------- 4.0 KEY REFERENCE The following table lists the keyboard keys which can be used in ImageLab: ESC - terminate an operation. Same as 'CANCEL'. RETURN - select an operation. Same as 'OK'. ENTER - same as return. HELP - invoke the help utility. SHIFT-UP - move the screen up 10 lines. SHIFT-DOWN - move the screen down 10 lines. AMIGA-A - Average. AMIGA-B - Color to black and white. AMIGA-C - Copy selected area. AMIGA-D - Display FFT. AMIGA-E - Edit/paint picture. AMIGA-F - FFT. AMIGA-G - Greyscale. AMIGA-H - Histogram. AMIGA-I - Inverse FFT. AMIGA-K - Close picture. AMIGA-L - Laplacian convolution. AMIGA-M - Move area. AMIGA-O - Open picture. AMIGA-P - Palette. AMIGA-R - Revert to old version. AMIGA-S - Save picture. AMIGA-X - Cut selected area. AMIGA-V - Paste selected area. AMIGA-Z - Undo last operation. AMIGA-- - Negative. AMIGA-_ - Vertical edge convolution. AMIGA-| - Horizontal edge convolution. AMIGA-, - Occupy all of screen. AMIGA-. - Occupy half of screen. AMIGA-/ - Occupy little of screen. ----------------------------------------------------------------------------- 5.0 COMMAND REFERENCE The following sections describe the function of each menu item in detail. Each is listed in alphabetical order. In general, each item has its own paragraphs; however, simple items are grouped unter the parent menu. ABOUT ----- The "About" menu item provides the requisite display of the program status (version number, etc.), a monitor of the free memory available (total), and access to the "help" system. AVERAGE ------- The "Average" item performs area averaging of the picture or selected area. Averaging is performed by using a 3x3 control matrix to select points of interest surrounding each pixel in the pixture (or selected area). For each non-zero term in the matrix, the corresponding pixel value is added to a sum. Then the center pixel is replaced by the average value. The effect of averaging an area is to reduce noise by blurring the area, in a manner similar to (but faster) the 'Smooth' convolution kernel. The various averaging options select different severities of smoothing The available suboptions are: HORIZONTAL VERTICAL H & V DIAGONAL ALL (A) CUSTOM... "Horizontal" averages based upon a pixels two neighbors to the left and right, using the following 3x3 matrix: 0 0 0 1 1 1 0 0 0 "Vertical" averages based upon the two neighbors above and below, using the following 3x3 matrix: 0 1 0 0 1 0 0 1 0 The "H & V" average combines the previous two methods to base the average on those four pixels, using the following 3x3 matrix: 0 1 0 1 1 1 0 1 0 The "Diagonal" average varies the previous one by using the four pixel at each corner, using the following 3x3 matrix: 1 0 1 0 1 0 1 0 1 The "All" average (the usual one) averages each pixel based upon all surrounding pixels. This produces the best average. It is based upon the following 3x3 matrix: 1 1 1 1 1 1 1 1 1 The "Custom..." option brings up a custom matrix editor. This window displays nine cells in a three by three format. You can select and edit the value in each of the cells. Enter a non-zero value to enable that location (pictorially speaking) to be used in the averaging, or leave it as zero to ignore that location. Options: If SHIFT is held when one of these options is selected, then the custom matrix editor is brought up with the contents of the selected averaging matrix. You can edit it to suit your needs. Note: the built-in matrices cannot be changed, they are fixed and will be reset each time you use them. If CTL is held while selecting an averaging option, then the sum of the selected pixels is always divided by 9 (the kernel size), instead of the number of pixels selected by the matrix. This has the effect of squashing the result into a darker image. BELL ---- The "Bell" item controls whether ImageLab signals an alarm on the completion of any operation. The options are: ON OFF If ON, then the Amiga's alarm function is calle. This will simply flash the screen by default, but several public domain functions are available which intercept this call and substitute an audible bell or sampled sound. The primary use of the bell function is to alert you when some of the lengthier functions have completed. Some functions, especially the FFT function, can take several minutes to complete. The bell is off by default, since they tend to be annoying. They can be enabled by the options: -b (from the CLI) BELL=ON (from the WorkBench) BINARY... --------- The "Binary..." function replaces each pixel with black if it is less than a specified limit, or with white if it is greater than or equal to that limit. The limit is specified by a sliding bar, which allows you to specify the color index number (0..max). The effect of the "Binary" functions is much like orthographic film: the result is pure black and white. Of course, the resolution is cut off sharply. CLEAR ----- The "Clear" operation sets the selected area to the background color. Options: If the SHIFT key is held, the area is set to the last color that was selected in the color palette. See: PALETTE CLOSE ----- Close closes the current picture and frees all associated memory items, including any FFT computations. If the picture has been modified but not saved, a warning requester will be displayed first. COLOR TO B&W ------------ The "Color to B&W" option converts a color picture to a black and white one (a grey scale, actually). This function is the primary tool used to allow ImageLab to process color IFF files (it is also known as the Un-Ted Turner function). "Color to B&W" uses the standard EIA weighting levels to obtains an evenly distributed grey scale. Note: if your picture has more than 16 colors, the greyscale will cause the picture to appear grainier -- this is a limitation of the Amiga DAC architecture. COLORS ------ The "Colors" item provides access to the color map functions for this picture. The available options are: PALETTE GREYSCALE NEGATIVE SATURATE PSEUDOCOLOR COLOR to B&W LINEARIZE DELETE COLORS... MAP COLORS... For information on the color operations, refer to the individual command descriptions. CONVOLVE -------- The "Convolve" item enables performing graphical convolution of the selected area. Convolution alters the center pixel by replacing it with the weighted pixel values in the surrounding area (usually including itself as well). The available convolve operations are: SMOOTH SHARPEN LAPLACIAN VERTICAL EDGE HORIZONTAL EDGE HIGH FREQUENCY LOW FREQUENCY CUSTOM... The "Custom..." option brings up a custom matrix editor. This window displays nine cells in a three by three format. You can select and edit the value in each of the cells. Each cells value will be multiplied by the corresponding pixel value, and the sum of all nine will be stored at the center pixel. For information on the other convolutions, refer to the individual command descriptions. Options: If SHIFT is held when one of these options is selected, then the custom matrix editor is brought up with the contents of the selected averaging matrix. You can edit it to suit your needs. Note: the built-in matrices cannot be changed, they are fixed and will be reset each time you use them. COPY ---- The "Copy" operation copies the selected area to the clipboard. CUT --- The "Cut" operation copies the selected area to the clipboard, then clears the resulting area to the background color. Options: If the SHIFT key is held, the area is set to the last color that was selected in the color palette. See: CLEAR, PALETTE DELETE... --------- The "Delete..." item calls up the file requester. Selecting a file and then the OK gadget will delete the that file. DELETE COLORS... ---------------- The "Delete Colors..." function beings up a requester which has a box for every possible color, numbered from 0..n. To delete a represented color, click on an open box and an 'X' will appear in it. When "OK" is selected, every marked color will be deleted from the picture. The remaining colors are then packed further down into the palette. "Delete Colors..." allows you to remap the color palette, possibly reducing the number of colors (and therefore, graphics bit planes) required. DISPLAY ------- The "Display" function causes ImageLab to open a screen and display the two-dimensional representation of the FFT you have computed (you cannot select this function unless FFT data is present, whether created or loaded). The "Display" function is controlled by the two options: "Log Display" and "Normal Display". Note: you do not have to re-compute the FFT if you only change the display modes. DISTORT... ---------- The "Distort..." function introduces distortion into the picture or selected area. Distortion is simulated by displacing the pixel in a random direction at random intervals (the distortion probability). A requester allows you to specify the approximate percentage probability that distortion will occur, from 0 (never) to 100 (always). EDIT PARAMETERS... ------------------ The "Edit Parameter..." function allows you to change the size, depth, or modes of the current picture. When selected, a requester is brought up, as follows: +-------------------------------------+ | Enter the new screen parameters: | | | | Width: 640 | | | | Height: 200 | | | | Depth: 5 | | | | [] HAM [] Interlace | | | | [] Extra-Half-Bright | | | | [ Ok ] [ Cancel ] | +-------------------------------------+ To enable a screen mode (HAM, Interlace, or Extra-Half-Bright), click in the box until an 'X' is present. To disable that mode, click until the 'X' is not present. Size parameters can be changed by editing the displayed values. Options: If the SHIFT key is held while "Edit Parameters..." is selected, it will ignore the selected area and will use the total size of the picture as the default size instead. Note: FFT data is preserved across this function, although its applicability is highly questionable. FFT --- The "FFT" Menu provides access to the FFT operations. The available functions are: TRANSFORM INVERSE -------------- TRANSLATION ON NO TRANSLATION -------------- DISPLAY LOG DISPLAY NORMAL DISPLAY -------------- FREE FFT For information on the FFT operations, refer to the individual command descriptions. FFT TOOLS --------- The "FFT Tools" menu performs operations on FFT data that has been generated. It has the following options: ZERO REAL ZERO IMAGINARY INVERT REAL PHASE RANDOMIZE The "Zero Real" option sets the real part of the complex FFT data to zero, while "Zero Imaginary" clears the imaginary part. "Invert Real" replaces the real part with its reciprocal. Phase randomize replaces the phase component of the FFT data with a random value (it must convert the data to polar form and back, so this can be slow). FILTER ------ The "Filter" menu provides access to various image filter methods other than the Convolve and Average functions. The available filters are: SOBEL ROBERTS BINARY... THRESHOLD... PIXELIZE... MINIMUM MEDIAN MAXIMUM ------------ DISTORT... NOISE... For information on the filter operations, refer to the individual command descriptions. FLIP ---- The "Flip" item flips the selected area around an imaginary axis. The "Horizontal" options flips it around an vertical axis, producing a mirror image. The "Vertical" options flips it around a horizontal axis, producing an upside-down image. FREE FFT -------- The "Free FFT" function releases all memory associated with an FFT. If you are pressed for space, this function will free up quite a bit, since 16 bytes are required for each pixel in the FFT area. GAMMA CORRECTION ---------------- The "Gamma Correction" applies a series of corrective factors to the greyscale color map, based upon empirical values for the Amiga monitor. These factors vary quite a bit; to alter them, hold down the SHIFT key when selecting "Gamma Correction" and a requester will allow you to enter other values for gamma, c, and I0. The default values are: gamma = 0.5 c = 1.75 I0 = 1.00 GREYSCALE --------- The "Greyscale" option sets the picture's color map to a linearly increasing range. This option automatically adjusts to different picture depths, but since the Amiga's video DAC's are only 4 bits wide, only 16-color pictures can make proper use of greyscale images. Pictures with more than 16 colors will have repeated grey colors, while those with less than 16 colors will have skipped values. HALFTONE... ----------- The "Halftone..." function allows the conversion of the current screen to a halftoned image. A requester allows the selection of a two-cell or three-cell halftone (note that this implies that the resulting picture will be two or three times as large as the selected area). HAM CONVERSION -------------- The "HAM Conversion" option is enabled only when the loaded picture is in HAM mode. Selecting this function converts the picture or selected area to a 4-plane greyscaled image. "HAM Conversion" correctly processes selected area that do not begin in the left-most column by scanning all pixels to the left of the selection area and tracking the resulting RGB values. HISTOGRAM --------- The "Histogram" function "Display" counts the number of each pixel value in the picture or selected area, and displays the totals. The "Equalize" function uses this information to "tweak" the color palette values to obtain a more uniform color distribution. The options for the Histogram Display function is: INCLUDE BLACK EXCLUDE BLACK BAR GRAPH LINE GRAPH The "Include Black" and "Exclude Black" options determine whether black colors are included in the display. Since the plot is automatically scaled to fit the main ImageLab display window, if your picture has a lot of black (as in a picture on a background), it will be hard to see the pixel distribution if the large number of black pixels flattens the curve. Normally, this is not a problem and black pixels are included. The "Bar Graph" and "Line Graph" options cause the histogram plot to be a bar graph or a line graph, as expected. Note: The Display options do not affect the Equalize function in any way. HORIZONTAL EDGE --------------- The "Horizontal Edge" operation uses graphical convolution to highlight horizontal edges (but not vertical ones). The kernel used is: -1 -1 -1 0 0 0 1 1 1 ICONS ----- The "Icons" item controls whether ImageLab creates an icon whenever a file is saved (via "Save" or "Save As..."). The options are: ON OFF If ON is selected, an icon is generated that resembles the Deluxe Paint (tm) icon, except that the default project is ImageLab. Icon generation defaults to off if ImageLab is run from the CLI, and to on if it is run from WorkBench. Icon generation can be controlled by the options: -b (from the CLI) ICON=OFF (from the WorkBench) INTENSITY --------- The "Intensity" item is used to alter the intensity of the picture or selected area. The first three options are: BRIGHTEN DARKEN OTHER... These functions incrementally add or subtract a value from the picture, causing the image to brighten or darken, respectively. The "Other..." option allows you to enter a step value other than one; to use it, enter the decimal step value you want, and click on the direction gadget (the 'delta' symbol to the left) to select the up direction ( /\ ) or the down direction ( \/ ). SCALE UP SCALE DOWN OTHER... These three function cause the intensity to be scaled more strongly than the previous three by using a multiplicative function. "Scale Up" scales each pixel value by 2 (overflow values are truncated at the maximum pixel intensity), while "Scale Down" halves its intensity. The "Other..." option works like the previously described requester, except that the value obtained from you is either multiplied or divided, depending upon the direction you select. ROOT The "Root" option dramatically scales down large intensity range by replacing each pixel by its square root. INVERSE ------- The "Inverse" operation computes the complex conjugate of the FFT data. If the data has not been modified, you can use Display and your original picture will be regenerated. If it has been altered in some way, you source may substantially return, with some errors introduced. The "Merge/XOR" function can quickly highlight changed pixels. Note: if translation is enabled, you picture will return rotated 180 degrees. You can use the "Flip" functions (both in sequence) to quickly correct this. LAPLACIAN --------- The "Laplacian" operation uses graphical convolution to highlight outline edges. The kernel used is: -1 -1 -1 -1 8 -1 -1 -1 -1 LINEARIZE --------- The "Linearize" option converts the palette to a monotonically increasing palette. ImageLab requires such a palette for its image processing function to perform properly. For example, if your four color palette is: 000 555 fff aaa the "Linearize" function will re-order it as: 000 555 aaa fff Note that this function requires rewriting all pixels in the picture in order to avoid changing its appearance. This function will be required for some DigiView pictures which do not use a linearly increasing palette. LOG DISPLAY ----------- If the "Log Display" option is enabled, the "Display" function will perform a logarithmic enhancement to the FFT data before displaying it. The dynamic range of the FFT falls off sharply along the axes from the DC component at zero. LOW FREQUENCY ------------- The "Low Frequency" kernel highlights unchanging areas. The kernel used is: -1 -1 -1 -1 1 -1 -1 -1 -1 MAP COLORS... ------------- The "Map Colors..." function operates similarly to "Delete Colors", except that only two colors can be selected. When "Ok" is selected, those two colors are exchanged in both the color map and the picture. See: DELETE COLORS... MAXIMUM ------- The "Maximum" function replaces each pixel with the maximum value found in the surrounding eight pixels. MEDIAN ------ The "Median" function replaces each pixel with the median value found in the surrounding eight pixels. Since a sort is required to find a median, this function is slower than the corresponding "Minimum" or "Maximum" functions. MERGE... -------- The "Merge" item is used to combine the current picture with another loaded from disk. The options available with merge are: OVERLAY ADD SUBTRACT AND OR XOR OTHER... The "Overlay" function copies all pixels in the merge picture onto the current one wherever the current one contains a zero pixel. The "Add" and "Subtract" functions perform arithmetic merges of the two pictures, paying attention to underflow/overflow issues. The "AND", "OR", "XOR", and "Other..." functions use the Amiga's blitter to perform the requested boolean operations. The "Other..." function allows custom blitter operations; to use, enter the blitter minterm as a decimal number (or i hex if you preceed it with '$'). Refer to the Amiga Hardware Reference Manual for details on the blitter. MINIMUM ------- The "Minimum" function replaces each pixel with the minimum value found in the surrounding eight pixels. MOVE ---- The "Move" item moves the pixels from the currently selected area to a destination of your choosing. When "Move" is selected, a draggable box is positioned on the screen. Click down to begin positioning it, and release the button when you are over the target area. Note: the image is copied off-screen first, so overlapping images can be produced. NEGATIVE -------- The "Negative" option reverses the order of the color map. If the picture currently has a greyscale color map, the picture will appear as a negative. This can make it easier to pick out features of the picture. Using this function on color pictures is... interesting -- you will generally want to convert it to black and white first. NO TRANSLATION -------------- The "No Translation" function disables the displacement of the FFT function to the center of the FFT area. With this option enabled, the FFT data places the DC component at the lower left corner, with reflection in all the other corners. Note: if the translation options is changed, you must re-compute the FFT for it to have any effect. NOISE... ---------- The "Noise..." function introduces impulse noise into the picture or selected area. Noise is generated by writing the brightest pixel (white) at random intervals (the noise probability). A requester allows you to specify the approximate percentage probability that noise will occur, from 0 (never) to 100 (always). Options: If SHIFT is held while making this selection, then the impulse noise generated will be the darkest color instead (black). NORMAL DISPLAY -------------- If the "Normal Display" option is enabled, the "Display" function will not perform a logarithmic enhancement to the FFT data before displaying it. Unless you source picture is quite extraordinary, all you will probably get is a white pixel at the DC term location. Use the "Log Display" option to enhance the display. OPEN... ------- The "Open..." item brings up a file requester (C. Heath's famous one). Select the IFF file you want to use, and select OK. ImageLab does not currently support SuperBitMap screens, so your picture must fit within the standard Intuition limits: about 720 x 500. If there is an image opened already, and it has been modified, then a requester will be displayed. Select "OK" to discard your changes, and proceed with loading the new image. Option: If SHIFT is held while making the "Open..." selection, then one bit plane will be stripped from the file while it is read in. This is useful to process Digi-View files (which have an extra bit plane in them) in ImageLab. This has the same effect as the "Restrict Palette" item, but conserves the memory that would otherwise be needed. PAINT ----- The "Paint" item puts creates a toolbox on the picture and allows you to modify the pixels with the mouse. The toolbox contains gadgets for: DRAW XOR RANDOM TRACE The "Draw" option draws the last color selected with the palette. If FFT data is present, the real component is changed to the selected color value. The "Xor" option toggles the pixels on the screen using the exclusive-or operator. If FFT data is present, the real component is replaced by the reciprocal. The "Random" option draws a random color on the screen. If FFT data is present, the real component is changed to a floating point random value. The "Trace" option works like "Draw", except that intermediate pixels are connected. This produces smooth line drawing. PALETTE... ---------- The "Palette..." option brings up a color palette on the screen. You can select a particular color from the block on the palette window, and alter its red, green, and blue components using the three sliders labelled R, G, and B. If you select "OK", the changes are added to your picture. If you select "Cancel", the old palette is restored. PASTE ----- The "Paste" item copies the contents of the clipboard into the current picture, if it is an IFF image. It the clipboard is empty, you will receive an error message. Otherwise, a draggable rectangle will be placed on the picture, which you can position where desired. Click once to begin dragging it, then release it over the position you want, and the data will be inserted. PICTURE INFO ------------ The "Picture Info" item opens a window and displays the following information about the picture file currently open: Name: .......... (name of the file) File Size: ..... (size in bytes) Size: .......... (size of the picture: L x W x H) Mode: .......... (picture modes: EHB, HAM, INTERLACE flags) Area: .......... (selected area, if any: location and size) FFT: ........... (number of bytes of FFT information available) POSITION -------- The "Position" item has some functions used to position the picture. Since there are no front/back gadgets, and no drag bar, positioning the screen is somewhat more difficult. The options are: SCREEN TO FRONT SCREEN TO BACK OCCUPY ALL OCCUPY MIDDLE OCCUPY LOW The FRONT and BACK items can also be performed by the LEFT-AMIGA M and LEFT-AMIGA N keys, respectively, if no other screen are open. The ALL, MIDDLE, and LOW items position the screen to occupy all, half, or a small portion of the WorkBench screen. The menu keys for these three functions are LEFT-AMIGA- ',', '.', and '/', respectively (chosen for convenience, not for any mnemonic function). PSEUDOCOLOR ----------- The "PsuedoColor" option converts the palette to values such that dark colors are tinted blue (i.e., "cold") and bright colors are tinted red (i.e., "hot"). Average colors are given a green hue. The effect is much like a thermograph, and tends to accentuate the difference between pixels. If the SHIFT key is held when the "Pseudo- Color" function is selected, the color map is randomized. This is mostly for fun. QUIT ---- The "Quit" item closes the picture and leaves ImageLab. If the picture has been modified but not saved, a requester will be brought up to give you a chance to save it first. RESIZE ------ The "Resize" item causes the selected item to be resized. The resizing options are: COPY INTERPOLATE HALVE DOUBLE The "Copy" and "Interpolate" items are operated identically: you drag the resizing rectangle to the desired size. When you release the mouse button, the selected area is scaled up or down to fit in the desired area (it is possible to scale up in one dimension and scale down in another at the same time). The difference between "Copy" and "Interpolate" arise when the area is expanded: "Copy" just copies the first pixel to fill the expanded area, while "Interpolate" employs bilinear interpolation to fill in the area. Interpolation produces a smoother picture, but is slower to operate. The "Halve" and "Double" options allow you to quickly resize the selected area to half or twice its original size, respectively. The "Double" operation employs interpolation for best results. Option: If SHIFT is held while selecting the target area, the selection box will be kept square. RESTRICT PALETTE ---------------- The "Restrict Palette" function if primarily used to deal with image files which have a palette larger than is necessary to represent the picture (i.e., the picture has 16 colors, but the palette has 32 locations reserved). This occurs often with DigiView pictures, which creates an extra bit-plane for internal control functions. The options are: ON OFF If ON, then the palette is halved (regardless of the total number). This option is reset to OFF whenever a new picture is loaded (or reverted), or when the screen parameters are edited. See also: EDIT PARAMETERS, OPEN PIXELIZE... ----------- The "Pixelize..." function replaces each pixel with <n> copies of itself, where <n> is from 2 to 10. This effect "computerizes" images, by craeting a blocky image of low resolution (i.e., IBM compatible). REVERT ------ The "Revert" menu item is enabled when any changes have been made to your image, or to its color-map. Selecting "Revert" recalls the file from disk. ROBERTS ------- The "Roberts" transform is a variation of the "Sobel" transform, both of which are effective at outline tracing. The Roberts transform uses the L->R, U->D, and diagonal gradients at each pixel location in the picture or selected area. SATURATE -------- The "Saturate" function converts the palette to values such that all colors are saturated (i.e, if a color is mostly red, it becomes pure red). Option: If the SHIFT key is held while selecting this function, then the intensity level is also intensified; this forces each pixel to a primary color. SAVE ---- The "Save" item allows writing to disk your current image file, and any changes that have been made to it. A user-settable option allows ImageLab to create icons and include ImageLab specific information in the IFF file. See Also: SAVE TYPE SAVE AS... ---------- The "Save As..." item allows writing to disk your current imageo using a different file name. Selecting this item brings up a file requester, allowing you to alter the current filename or enter a new one. If OK is selected, then the file is saved as described in the "Save" function. SAVE TYPE --------- The "Save Type" item specifies how pictures will be saved. The first three items are: NO COMPRESSION COMPRESS RUNS CHOOSE which are mutually exclusive. The first two items can be selected to indicate what type of data compression to use in the IFF picture file. The default is to save in the mode that the currently open picture was originally saved (usually "COMPRESS RUNS"). If the special item 'CHOOSE' is selected, ImageLab will write out the file using both methods, then bring up a requester showing the total file sizes using both methods. You can then elect to save the smallest one. The second set of Save options are: NO FFT DATA SAVE FFT DATA which control the saving of any FFT data generated by the FFT function. By default, this is disabled, since ImageLab uses a custom IFF id to do so (this *should* be transparent to picture display programs, but that is not always true). SHARPEN ------- The "Sharpen" operation uses graphical convolution to accentuate the differences between the center pixel and the surrounding ones. The kernel used is: -1 -1 -1 -1 9 -1 -1 -1 -1 SMOOTH ------ The "Smooth" operation uses graphical convolution to smooth the area selected by using the smoothing kernel: 1 1 1 1 1 1 1 1 1 SOBEL ----- The "Sobel" transform is a highly effective outline tracing function, which examines the gradients present at each pixel location in the picture or selected area. THRESHOLD... ------------ The "Threshold..." function reduces the range of a picture or selected area by clipping pixels which fall outside a user-defined range. Values outside this range are clipped to the minimum or maximum, as appropriate. To select a threshold, a requester is brought up which has two sliders on it: adjust the minimum and maximum values to your desired range. Note: the requester will reject attempts to set a minimum greater than a maximum. TRANSFORM --------- The "Transform" function invokes ImageLab's two-dimensional FFT routine. FFT's convert time domain information (a picture is a valid representation of this) to frequency domain information. Using the default settings, the transform of an image produces a strong DC component at the center (representing the uniform background) with sine circles radiating outwards (representing the edge frequencies of components in the picture). Refer to any good textbook for a better explanation of this. When the FFT has been computed, you can use the "Paint" functio to introduce errors in the transform, and use the "Inverse" function to try to recover your picture. For fun, try blotting out the strong DC term in the center of the picture. ImageLab uses an FFT instead of a DFT for speed; however, FFT's must be a power of two in both dimensions (2, 4, 8, etc.). If the picture or selected area is not a power of two in size, the FFT Size requestor is brought up first. This requester looks like: +--------------------------------------------------+ | The selected FFT area must be a power of two in | | size. Adjust the desired size: | | | | +---------+---------------+ | | |@+--+@@@@| | | | |@+--+@@@@| | [] Overscan | | |---------+ | | | | | Size: /\ | | | | < > | | | | \/ | | +-------------------------+ | | Select: (77,18)..(140,33) Area: [64 x 16] | | Screen size: (320,200) | | FFT Max: (1024,1024) | | | | [ Ok ] [ Cancel ] | +--------------------------------------------------+ To alter the size of the selected area, click on the arrow gadgets. The "up" and "left" arrow reduce the Y and X dimensions, respectively; the "down" and "right" arrows increase them. You can also use the arrow keys on the keyboards. To alter the origin of the selected area, use the arrow gadgets as described before, but hold the SHIFT key down while clicking on the gadgets or using the keyboard. This steps the origin by one in the selected direction; if the ALT key is also held, the origin shifts by ten. If the "Overscan" gadget is selected, you can perform FFT's of entire pictures (if you have enough memory). Selecting this gadget transforms the requester as shown: +--------------------------------------------------+ | The selected FFT area must be a power of two in | | size. Adjust the desired size: | | | | +-------------------------+ | | | | | | | +-----------+ | [] Overscan | | | | @@@@@@@ | | | | | | @@@@@@@ | | Size: /\ | | | +-----------+ | < > | | | | \/ | | +-------------------------+ | | Select size: (512,256) | | Screen size: (320,200) | | FFT Max: (1024,1024) | | | | [ Ok ] [ Cancel ] | +--------------------------------------------------+ The FFT Transform function pads the FFT data to fill in the unspecified areas when overscan is performed. When the FFT is properly set up, select OK to begin the transform. This can take some time for FFT's over about 32 by 32 (on a standard MC68000 Amiga). A bar chart tracks the FFT's progress in the ImageLab display window. Note: the only functions which can alter the associated FFT data is the "Paint" function. Options: If the SHIFT key is held while selecting "Transform", then the FFT Size requester is brought up regardless of the selected size. TRANSLATION ON -------------- The "Translation On" function enables the displacement of the FFT function to the center of the FFT area. Without this option enabled, the FFT data places the DC component at the lower left corner, with reflection in all the other corners. Note: if the translation options is changed, you must re-compute the FFT for it to have any effect. UNDO ---- The "Undo" operation attempts to undo the last operation that was done. Undo works well with color palette changes, but currently cannot undo changes to the picture itself; use the "Revert" command for that. Only one level of "undo" is supported. UNSELECT -------- The "Unselect" operation clears the select rectangle from the picture, causing all ImageLab operations to be performed on the entire picture. VERTICAL EDGE ------------- The "Vertical Edge" operation uses graphical convolution to highlight vertical edges (but not horizontal ones). The kernel used is: -1 0 1 -1 0 1 -1 0 1