Plan for Image Processing Utilities
Introduction
Carrying forward from my proposal on the wiki page and Google-Mellange. In this page I add, improvements for my plan and detail it further. Here I add points from my trunk (collected since the proposal day) and would like valuable feedback from the core-developers, so that the plan is in sync with the organization's goal and needs.
Key Points
- There are arount 125 utilities in total in the /src/util folder. Not all of these utilities, are image processing tools.
- There are around 35 tools which deals in conversion of one format to other.
- Other Image Processing Functions to be implemented have been divided into Groups based on there similarities in implementation and such that each week during the
development phase 1-2 Groups could be implemented. Details of this will be discussed in further sections.
Image Conversions
The week from July 1 - July 15 during the development phase is dedicated to import/export. I have been working on this front and have submitted few patches. Although fine tuning is required. Once the complete Import Export Functions (very few are left) are deployed Image conversions becomes very easy. Following is a table which describes the current image conversions tools.
| alias-pix | Convert ALIAS(tm) PIX format image files to BRL PIX format files. |
| ap-pix | Applicon color ink jet printer to .pix file converter. |
| bw-a | Convert a bw file into an ASCII bitmap. |
| bw-pix | Merge three BW files into one RGB pix file. (i.e. combine the colors) |
| bw-png | Convert bw file to PNG (Portable Network Graphics) format |
| bw-ps | Convert a black and white (bw) file to an 8-bit PostScript image. |
| bw-rle | Encode a .bw file using the Utah Raster Toolkit RLE library |
| bw3-pix | Convert an 8-bit black and white file to a 24-bit color one by replicating each value three times. |
| pix-alias | Convert BRL PIX format image files to ALIAS(tm) PIX format files. |
| pix-bw | Converts a RGB pix file into an 8-bit BW file. |
| pix-bw3 | Converts a RGB pix file into 3 8-bit BW files. |
| pix-orle | Encode a .pix file using the old ORLE library |
| pix-png | Convert pix file to PNG (Portable Network Graphics) format |
| pix-ppm | convert BRL .pix files to ppm |
| pix-ps | Convert an RGB (pix) file to an 24-bit color PostScript image. |
| pix-rle | Encode a .pix file using the Utah Raster Toolkit RLE library |
| pix-spm | Turn a pix file into sphere map data. |
| pix-sun | Program to take a BRL-CAD PIX format image file and convert the image to a Sun Microsystems 8-bit deep color "rasterfile" format image. |
| pix-yuv | Convert a .pix file to a .YUV file, i.e. in CCIR-601 format. |
| pl-asc | Plot3(5) to ASCII converter. |
| pl-dm | Example application that shows how to hook into the display manager. |
| pl-hpgl | Convert a unix-plot file to hpgl codes. |
| pl-pl | Gets rid of (floating point, flush, 3D, color, text). |
| pl-ps | Display plot3(5) as PostScript. Based on pl-X and bw-ps |
| pl-tek | Convert 3-D color extended UNIX-plot file to Tektronix 4014 plot. Gets rid of (floating point, flush, 3D, color, text). |
| pl-X | Display plot3(5) on an X Window System display (X11R2) lcolor |
| png-bw | Display info about a PNG (Portable Network Graphics) format file |
| png-pix | Convert PNG (Portable Network Graphics) format to pix |
| mac-pix | Read MacPaint document and output pix(5) or bw(5) raster image |
| orle-pix | |
| sun-pix | Program to take Sun bitmap files created with Sun's ``screendump'' command, and convert them to pix(5) format files. |
| xyz-pl | Program to take input with up to 3 white-space separated columns, expressed as x y z and produce a 3-D UNIX-plot file of the resulting space curve. |
| yuv-pix | Convert a .yuv file to a .pix file, i.e. in CCIR-601 format. |
This tools will be converted to IP functions. The structure of the function (not finalized) might look like the following.
int icv_convert(char* input_filename, struct icv_size* input_size, char* output_filename, int cvt2status)
Other Image Processing Functions
I have chosen a set of image processing functionalities and divided them into groups with similar implementation details. This division will also help during development phase. During each week 1-2 Groups will be chose. Details of the combinations for each week are being studied at present so that load is balanced in each week. This will also ensure and bring more structure in the current plan, thus minimizing the implementation risk. Details of each group is given in the following sections. Although in days to come more group specific comments will be added.
Crop or Rect (GROUP#1)
- bwrect Remove a portion of a potentially huge .bw file.
- pixrect Remove a portion of a potentially huge pix file.
- bwcrop Crop Black and White files.
- pixcut Extract a piece of a pix file. If the parameters of the file to be extracted do not fit within the original pix file then the extra area is filled with a background solid color.
Comments
Differences and other arithmetic operations (GROUP#2)
- bwdiff Take the difference between two BW files. Output is: (file1-file2)/2 + 127
- pixdiff Compute the difference between two .pix files. To establish context, a half-intensity monochrome image is produced when there
- pixsaturate A saturation value of 0 gives monochrome, 1.0 gives the original image, and values larger than 1.0 give a more saturated image.
- bwmod Modify intensities in Black and White files. Allows any number of add, subtract, multiply, divide, or
Comments
Filters, (GROUP#3)
- bwfilter Filters a black and white file with an arbitrary 3x3 kernel. Leaves the outer rows untouched.
- pixfilter Filters a color pix file with an arbitrary 3x3 kernel. Leaves the outer rows untouched. Allows an alternate divisor and offset to be given.
- pix3filter Filters a color pix file set with an arbitrary 3x3x3 kernel. Leaves the outer rows untouched.
- pixfade Fade a picture
Comments
Histograms and Equalizations (GROUP#4)
- bwhisteq Build up the histogram of a picture and output the "equalized" version of it on stdout.
- bwhist Display, and optionally dump to tty, a histogram of a black and white file. Black is top of screen, white bottom.
- pixhist Display a color histogram of a pix file. 0 is top of screen, 255 bottom.
Comments
Scale or Shrink (GROUP#5)
- bwscale Scale a black and white picture.
- pixscale Scale an RGB pix file.
- bwshrink scale down a picture by a uniform factor.
- pixshrink scale down a picture by a uniform factor.
Comments
Stats (GROUP#6)
- bwstat Compute statistics of pixels in a black and white (BW) file. Gives min, max, mode, median, mean, s.d., var, and skew.
- pixstat Compute statistics of pixels in a PIX file.
- pixcolors Count the number of different pixel values in a PIX format image.
- pixcount Sort the pixels of an input stream by color value.
- imgdims Guess the dimensions of an image
Comments
Thresh (GROUP#7)
- bwthresh Threshold data in BW(5) format. thresholds stream of data.
- pixclump Quantize the color values in a PIX(5) stream to a set of specified values
Comments
Interpolate/Decimate (GROUP#8)
- pixhalve Reduce the resolution of a .pix file by one half in each direction, using a 5x5 pyramid filter.
- pixinterp2x Read a .pix file of a given resolution, and produce one with twice as many pixels by interpolating between the pixels.
Comments
Background and Border (GROUP#9)
- pixbackgnd Background Maker
- pixbgstrip Background Un-Maker
- pixborder Add a 1-pixel-wide border to regions of a specified color
Comments
Merge or Split (GROUP#10)
- pixmerge Given two streams of data, typically pix(5) or bw(5) images, generate an output stream of the same size, where the value of the output is determined by a formula involving the first (foreground) stream and a constant, or the value of the second (background) stream.
- pixdsplit Disentangle the chars from the doubles in a pixd(5) stream
- pixfields (not exactly Merge Split but similar) * pixfields takes two input pictures and extracts field 1 from the first pix file and field 2 comes from the second pix file. This is useful for creating field-by-field animation for NTSC video display.
- pixfieldsep (not exactly Merge Split but similar) * Separate an interlaced video image into two separate .pix files.
Comments
Morphing and other Misc (GROUP#11)
- pixmorph Utility for morphing two BRL-CAD pix files.
- pixtile Given multiple .pix files with ordinary lines of pixels, produce a single image with each image side-by-side, right to left, bottom to top on STDOUT.
- pixuntile Given a single .pix file with multiple images, each side-by-side, right to left, bottom to top, break them up into separate .pix files.
- pixembed Embed a smaller pix file in a larger space, replicating the boundary pixels to fill out the borders, and output as a pix file.
- pixpaste pixpaste will insert an arbitrary pix file into another pixfile. If the image being pasted does not fit within the destination file then the excess is discarded.
- pixmatte Given four streams of data elements, where element is of arbitrary width, typically pix(5) or bw(5) images, output a stream of the same number of data elements.
- pixelswap interchange pixel values in an image
Comments
Feasibility
The above functionalities were grouped with associated commonalities. These functionalties will be added as part of the ICV library. These list of functionalities have been drawn from the Image Processing Tools available with brlcad which indeed is the aim of this project.
Thus the implemnetation task will envolve syncing the tools with structures of LIBICV and the said functionalities to the library. This will help in inter-function communication with the whole BRLCAD source.
Also once all the structures are identified (work is cuurently underway), syncing and implemneting a function will require very few functional points. And thus is also feasible.