convert(1) User Commands convert(1) NAME convert - converts an input file using one image format to an output file with a differing image format. SYNOPSIS convert [ _o_p_t_i_o_n_s ... ] _i_n_p_u_t__f_i_l_e _o_u_t_p_u_t__f_i_l_e DESCRIPTION convert converts an input file using one image format to an output file with a differing image format. convert recognizes the following image formats: Tag Description ------------------------------------------------------------------------------- AVS AVS X image file. BIE+ Joint Bi-level Image experts Group file interchange format. BMP+ Microsoft Windows bitmap image file. CMYK Raw cyan, magenta, yellow, and black bytes. DCX+ ZSoft IBM PC multi-page Paintbrush file. DIB Microsoft Windows bitmap image file. EPS Adobe Encapsulated PostScript file. EPS2 Adobe Level II Encapsulated PostScript file. EPSF Adobe Encapsulated PostScript file. EPSI Adobe Encapsulated PostScript Interchange format. FAX+ Group 3. FITS Flexible Image Transport System. GIF+ CompuServe graphics interchange format; 8-bit color. GIF87+ CompuServe graphics interchange format; 8-bit color (version 87a). GRAY Raw gray bytes. GRADATION gradual passing from one shade to another. Specify ImageMagick Last change: 19 Feb 1995 1 convert(1) User Commands convert(1) the desired shading as the filename (e.g. gradation:red-blue). HDF+ Hierarchical Data Format. HTML Hypertext Markup Language with a client-side image map. HISTOGRAM JBIG+ Joint Bi-level Image experts Group file interchange format. JPEG Joint Photographic Experts Group JFIF format; compressed 24-bit color. MAP Red, green, and blue colormap bytes followed by the image colormap indexes. MATTE Raw matte bytes. MIFF+ Magick image file format. MONO Bi-level bitmap in least-significant-byte (LSB) first order. MPEG+ Motion Picture Experts Group file interchange format. MTV+ MTV Raytracing image format. NULL NULL image. PBM+ Portable bitmap format (black and white). PCD Photo CD. PCL Page Control Language. PCX ZSoft IBM PC Paintbrush file. PDF+ Portable Document Format. PGM+ Portable graymap format (gray scale). PICT Apple Macintosh QuickDraw/PICT file. PNG Portable Network Graphics. PNM+ Portable anymap. PPM+ Portable pixmap format (color). ImageMagick Last change: 19 Feb 1995 2 convert(1) User Commands convert(1) PS+ Adobe PostScript file. PS2+ Adobe Level II PostScript file. RAD Radiance image format. RGB Raw red, green, and blue bytes. RGBA Raw red, green, blue and matte bytes. RLA Alias/Wavefront image file; read only RLE Utah Run length encoded image file; read only. SGI+ Irix RGB image file. SHTML Hypertext Markup Language with a client-side image map. SUN+ SUN Rasterfile. TEXT raw text file; read only. TGA+ Truevision Targa image file. TIFF+ Tagged Image File Format. TILE tile image with a texture. UYVY 16bit/pixel interleaved YUV (e.g. used by AccomWSD). VICAR read only. VID Visual Image Directory. VIFF+ Khoros Visualization image file. X select image from X server screen. XC constant image of X server color. Specify the desired color as the filename (e.g. xc:yellow). XBM X11 bitmap file. XPM X Windows system pixmap file (color). XWD X Windows system window dump file (color). YUV CCIR 601 4:1:1 file. YUV3 CCIR-601 4:1:1 files. ImageMagick Last change: 19 Feb 1995 3 convert(1) User Commands convert(1) Note, a format delineated with + means that if more than one image is specified, it is combined into a single multi-image file. Use +adjoin if you want a single image produced for each frame. Raw images are expected to have one byte per pixel unless ImageMagick is compiled in 16-bit mode. Here, the raw data is expected to be stored two bytes per pixel in most- significant-byte-first order. EXAMPLES To convert a _M_I_F_F image of a cockatoo to a SUN raster image, use: convert cockatoo.miff sun:cockatoo.ras To convert a multi-page _P_o_s_t_s_c_r_i_p_t document to individual FAX pages, use: convert -monochrome document.ps fax:page To convert a TIFF image to a _P_o_s_t_s_c_r_i_p_t A4 page with the image in the lower left-hand corner, use: convert -page A4+0+0 image.tiff document.ps To convert a raw GRAY image with a 128 byte header to a portable graymap, use: convert -size 768x512+128 gray:raw image.pgm To convert a Photo CD image to a TIFF image, use: convert -size 1536x1024 img0009.pcd image.tiff convert img0009.pcd[4] image.tiff To create a visual image directory of all your JPEG images, use: convert 'vid:*.jpg' directory.miff To annotate an image with blue text using font 12x24 at position (100,100), use: convert -font 12x24 -pen blue -draw "text +100+100 Cockatoo" bird.jpg bird.miff To tile a 640x480 image with a JPEG texture with bumps use: convert -size 640x480 tile:bumps.jpg tiled.png ImageMagick Last change: 19 Feb 1995 4 convert(1) User Commands convert(1) To surround an icon with an ornamental border to use with Mosaic(1), use: convert -mattecolor #ccc -frame 6x6 bird.jpg icon.png To create a GIF animation image from a DNA molecule sequence, use: convert -delay 20 -page +50+100 dna.* dna.gif OPTIONS -adjoin join images into a single multi-image file. -blur _f_a_c_t_o_r blurs an image. Specify _f_a_c_t_o_r as the percent enhance- ment (0.0 - 99.9%). -border <_w_i_d_t_h>_x<_h_e_i_g_h_t> surround the image with a border of color. See X(1) for details about the geometry specification. The color of the border is specified with the -border- color command line option. -box _c_o_l_o_r set the color of the annotation bounding box. See -draw or for further details. See X(1) for details about the color specification. -colors _v_a_l_u_e preferred number of colors in the image. The actual number of colors in the image may be less than your request, but never more. Note, this is a color reduction option. Images with less unique colors than specified with this option will remain unchanged. Refer to quantize(9) for more details. Note, options -dither, -colorspace, and -treedepth affect the color reduction algorithm. -colorspace _v_a_l_u_e the type of colorspace: GRAY, OHTA, RGB, Transparent, XYZ, YCbCr, YIQ, YPbPr, or YUV. Color reduction, by default, takes place in the RGB color space. Empirical evidence suggests that dis- tances in color spaces such as YUV or YIQ correspond to perceptual color differences more closely than do dis- tances in RGB space. These color spaces may give ImageMagick Last change: 19 Feb 1995 5 convert(1) User Commands convert(1) better results when color reducing an image. Refer to quantize(9) for more details. The Transparent color space behaves uniquely in that it perserves the matte channel of the image if it exists. The -colors or -monochrome option is required for this option to take effect. -comment _s_t_r_i_n_g annotate an image with a comment. By default, each image is commented with its file name. Use this option to assign a specific comment to the image. Optionally you can include the image filename, type, width, height, or scene number by embedding spe- cial format characters. Embed %f for filename, %m for magick, %w for width, %h for height, %s for scene number, %b for file size in kilobytes, or \n for new- line. For example, -comment "%m:%f %wx%h" produces an image comment of MIFF:bird.miff 512x480 for an image titled bird.miff and whose width is 512 and height is 480. If the first character of _s_t_r_i_n_g is @, the image com- ment is read from a file titled by the remaining char- acters in the string. -compress _t_y_p_e the type of image compression: _Z_i_p or _R_u_n_l_e_n_g_t_h_E_n_c_o_d_e_d. Specify +compress to store the binary image in an uncompressed format. The default is the compression type of the specified image file. -contrast enhance or reduce the image contrast. This option enhances the intensity differences between the lighter and darker elements of the image. Use -contrast to enhance the image or +contrast to reduce the image contrast. -crop <_w_i_d_t_h>{%}_x<_h_e_i_g_h_t>{%}{+-}<_x _o_f_f_s_e_t>{+-}<_y _o_f_f_s_e_t> preferred size and location of the cropped image. See X(1) for details about the geometry specification. To specify a percentage width or height instead, append %. For example to crop the image by ten percent on all ImageMagick Last change: 19 Feb 1995 6 convert(1) User Commands convert(1) sides of the image, use -crop 10%. Use cropping to crop a particular area of an image. Use -crop 0x0 to remove edges that are the background color. Omit the x and y offset to generate one or more subimages of a uniform size. -cycle _a_m_o_u_n_t displace image colormap by amount. _A_m_o_u_n_t defines the number of positions each colormap entry is shifted. -delay <_1/_1_0_0_t_h_s _o_f _a _s_e_c_o_n_d> display the next image after pausing. This option is useful for regulating the animation of a sequence of GIF images within Netscape. _1/_1_0_0_t_h_s _o_f _a _s_e_c_o_n_d must expire before the redisplay of the image sequence. The default is no delay between each showing of the image sequence. -density <_w_i_d_t_h>_x<_h_e_i_g_h_t> vertical and horizontal resolution in pixels of the image. This option specifies an image density when decoding a Postscript or Portable Document page. The default is 72 pixels per inch in the horizontal and vertical direction. -despeckle reduce the speckles within an image. -display _h_o_s_t:_d_i_s_p_l_a_y[._s_c_r_e_e_n] specifies the X server to contact; see X(1). -dispose _m_e_t_h_o_d GIF disposal method. Graphics Interchange Format (GIF) Specification 89a of July 31, 1990 for details. -dither apply Floyd/Steinberg error diffusion to the image. The basic strategy of dithering is to trade intensity resolution for spatial resolution by averaging the intensities of several neighboring pixels. Images which suffer from severe contouring when reducing colors can be improved with this option. ImageMagick Last change: 19 Feb 1995 7 convert(1) User Commands convert(1) The -colors option is required for dithering to take effect. -draw _s_t_r_i_n_g annotate an image with one or more graphic primitives. Use this option to annotate an image with one or more graphic primitives. The primitives include rectangle circle polygon color matte text image Rectangle, color, matte, text, and image require an upper left and lower right coordinate. Circle requires the center coordinate and a coordinate on the outer edge. Finally, polygon requires three or more coordi- nates defining its boundaries. Coordinates are integers separated by an optional comma. For example, to define a circle centered at 100,100 that extends to 150,150 use: -draw 'circle 100,100 150,150' Use color to change the color of a pixel. Follow the pixel coordinate with a method: point replace floodfill reset Consider the target pixel as that specified by your coordinate. The point method recolors the target pixel. The replace method recolors any pixel that matches the color of the target pixel. Floodfill recolors any pixel that matches the color of the target pixel and is a neighbor. Finally, reset recolors all pixels. Use matte to the change the pixel matte value to tran- sparent. Follow the pixel coordinate with a method (see the color primitive for a description of methods). The point method changes the matte value of the target pixel. The replace method changes the matte value of any pixel that matches the color of the target pixel. Floodfill changes the matte value of any pixel that matches the color of the target pixel and is a ImageMagick Last change: 19 Feb 1995 8 convert(1) User Commands convert(1) neighbor. Finally reset changes the matte value of all pixels. Use text to annotate an image with text. Follow the text coordinates with a string. If the string has embedded spaces, enclose it in double quotes. Option- ally you can include the image filename, type, width, height, or scene number by embedding special format characters. Embed %f for filename, %m for magick, %w for width, %h for height, %s for scene number, %b for file size in kilobytes, or \n for newline. For exam- ple, -draw 'text 100,100 "%m:%f %wx%h"' annotates the image with MIFF:bird.miff 512x480 for an image titled bird.miff and whose width is 512 and height is 480. If the first character of the string is @, the text is read from a file titled by the remaining characters in the string. Use image to composite an image with another image. Follow the image coordinates with the filename of an image. If the first character of _s_t_r_i_n_g is @, the text is read from a file titled by the remaining characters in the string. You can set the primitive color, font color, and font bounding box color with -pen, -font, and -box respec- tively. Options are processed in command line order so be sure to use -pen _b_e_f_o_r_e the -draw option. -edge _f_a_c_t_o_r detect edges with an image. Specify _f_a_c_t_o_r as the per- cent enhancement (0.0 - 99.9%). -emboss emboss the image. -enhance apply a digital filter to enhance a noisy image. -equalize perform histogram equalization to the image. -flip create a "mirror image" by reflecting the image scan- lines in the vertical direction. ImageMagick Last change: 19 Feb 1995 9 convert(1) User Commands convert(1) -flop create a "mirror image" by reflecting the image scan- lines in the horizontal direction. -font _n_a_m_e use this font when annotating the image with text. Convert contacts an X server to obtain the font. If an X server is not available, a Postscript font is used. You can set the pointsize with -pointsize. - frame <_w_i_d_t_h>_x<_h_e_i_g_h_t>+<_o_u_t_e_r _b_e_v_e_l _w_i_d_t_h>+<_i_n_n_e_r _b_e_v_e_l _w_i_d_t_h> surround the image with an ornamental border. See X(1) for details about the geometry specification. The color of the border is specified with the -mat- tecolor command line option. -gamma _v_a_l_u_e level of gamma correction. The same color image displayed on two different works- tations may look different due to differences in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values extend from 0.8 to 2.3. You can apply separate gamma values to the red, green, and blue channels of the image with a gamma value list delineated with commas (i.e. 1.7,2.3,1.2). -geometry <_w_i_d_t_h>{%}_x<_h_e_i_g_h_t>{%}{!}{<}{>} preferred size or location of the image when encoding. By default, the width and height are maximum values. That is, the image is expanded or contracted to fit the width and height value while maintaining the aspect ratio of the image. Append an exclamation point to the geometry to force the image size to exactly the size you specify. For example, if you specify 640x480! the image width is set to 640 pixels and height to 480. If only one factor is specified, both the width and height assume the value. To specify a percentage width or height instead, append %. The image size is multiplied by the width and height percentages to obtain the final image dimen- sions. To increase the size of an image, use a value greater than 100 (e.g. 125%). To decrease an image's size, use a percentage less than 100. ImageMagick Last change: 19 Feb 1995 10 convert(1) User Commands convert(1) Use < to change the dimensions of the image _o_n_l_y if its size exceeds the geometry specification. > resizes the image _o_n_l_y if its dimensions is less than the geometry specification. For example, if you specify 640x480> and the image size is 512x512, the image size does not change. However, if the image is 1024x1024, it is resized to 640x480. There are 72 pixels per inch in Postscript coordinates. -implode _f_a_c_t_o_r implode image pixels about the center. Specify _f_a_c_t_o_r as the percent implosion (0 - 99.9%) or explosion (- 99.9 - 0%). -interlace _t_y_p_e the type of interlacing scheme: NONE, LINE, or PLANE. The default is PLANE. This option is used to specify the type of interlacing scheme for raw image formats such as RGB or YUV. NONE means do not interlace (RGBRGBRGBRGBRGBRGB...), LINE uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and PLANE uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...). Use LINE, or PLANE to create an interlaced GIF or pro- gressive JPEG image. -label _n_a_m_e assign a label to an image. Use this option to assign a specific label to the image. Optionally you can include the image filename, type, width, height, or scene number in the label by embedding special format characters. Embed %f for filename, %m for magick, %w for width, %h for height, %s for scene number, %b for file size in kilobytes, or \n for newline. For example, -label "%m:%f %wx%h" produces an image label of MIFF:bird.miff 512x480 for an image titled bird.miff and whose width is 512 and height is 480. If the first character of _s_t_r_i_n_g is @, the image label is read from a file titled by the remaining characters in the string. When converting to Postscript, use this option to specify a header string to print above the image. -loop _i_t_e_r_a_t_i_o_n_s add Netscape loop extension to your GIF animation. ImageMagick Last change: 19 Feb 1995 11 convert(1) User Commands convert(1) A value other than zero forces the animation to repeat itself up to _i_t_e_r_a_t_i_o_n_s times. -map _f_i_l_e_n_a_m_e choose a particular set of colors from this image. By default, color reduction chooses an optimal set of colors that best represent the original image. Alter- natively, you can choose a particular set of colors with this option. -matte store matte channel if the image has one. -modulate _v_a_l_u_e vary the brightness, saturation, and hue of an image. Specify the percent change in brightness, the color saturation, and the color hue separated by commas. For example, to increase the color brightness by 20% and decrease the color saturation by 10% and leave the hue unchanged, use: -modulate 20,-10. -monochrome transform the image to black and white. -negate apply color inversion to image. The red, green, and blue intensities of an image are negated. Use +negate to only negate the grayscale pix- els of the image. -noise reduce the noise in an image with a noise peak elimina- tion filter. The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired struc- tures. The central idea of the algorithm is to replace a pixel with its next neighbor in value within a 3 x 3 window, if this pixel has been found to be noise. A pixel is defined as noise if and only if this pixel is a maximum or minimum within the 3 x 3 window. -normalize transform image to span the full range of color values. This is a contrast enhancement technique. -opaque _c_o_l_o_r ImageMagick Last change: 19 Feb 1995 12 convert(1) User Commands convert(1) change this color to the pen color within the image. See -pen for more details. -page <_w_i_d_t_h>_x<_h_e_i_g_h_t>{+-}<_x _o_f_f_s_e_t>{+-}<_y _o_f_f_s_e_t> preferred size and location of the Postscript page. Use this option to specify the dimensions of the Postscript page in pixels per inch or a TEXT page in pixels. The default for a Postscript page is to center the image on a letter page 612 by 792 pixels. The mar- gins are 1/2" (i.e. 612x792+42+42). Other common sizes are: Letter 612x 792 Tabloid 792x1224 Ledger 1224x 792 Legal 612x1008 Statement 396x 612 Executive 540x 720 A3 842x1190 A4 595x 842 A5 420x 595 B4 729x1032 B5 516x 729 Folio 612x 936 Quarto 610x 780 10x14 720x1008 For convenience you can specify the page size by media (e.g. A4, Ledger, etc.). To place a Postscript image with a given size on a given location on a page, use -page +HOFFSET+VOFFSET -geometry WIDTHxHEIGHT (fill in numbers). Note: this is only for gen- erating Postscript, not Encapsulated Postscript. To position a GIF image, use -page +LEFT+TOP (e.g. -page +100+200). The default page dimensions for a TEXT image is 612x792. -paint _r_a_d_i_u_s paint the image. Each pixel is replaced by the most frequent color in a circular neighborhood whose width is specified with _r_a_d_i_u_s. -pen _c_o_l_o_r set the color of the font or opaque color. See -anno- tate or -draw for further details. ImageMagick Last change: 19 Feb 1995 13 convert(1) User Commands convert(1) See X(1) for details about the color specification. -pointsize _v_a_l_u_e pointsize of the Postscript font. -quality _v_a_l_u_e JPEG quality setting. Quality is 0 (worst) to 100 (best). The default is 75. -raise <_w_i_d_t_h>_x<_h_e_i_g_h_t> lighten or darken image edges to create a 3-D effect. See X(1) for details about the geometry specification. Use -raise to create a raised effect, otherwise use +raise. -region <_w_i_d_t_h>_x<_h_e_i_g_h_t>{+-}<_x _o_f_f_s_e_t>{+-}<_y _o_f_f_s_e_t> apply options to a portion of the image. By default, any command line options are applied to the entire image. Use -region to restrict operations to a particular area of the image. -roll {+-}<_x _o_f_f_s_e_t>{+-}<_y _o_f_f_s_e_t> roll an image vertically or horizontally. See X(1) for details about the geometry specification. A negative _x _o_f_f_s_e_t rolls the image left-to-right. A negative _y _o_f_f_s_e_t rolls the image top-to-bottom. -rotate _d_e_g_r_e_e_s apply Paeth image rotation to the image. Empty triangles left over from rotating the image are filled with the color defined as bordercolor (class borderColor). See X(1) for details. -sample _g_e_o_m_e_t_r_y scale image with pixel sampling. -scene _v_a_l_u_e image scene number. -segment _v_a_l_u_e eliminate clusters that are insignificant. The number of pixels in each cluster must exceed the the cluster threshold to be considered valid. See IMAGE SEGMENTATION for details. -sharpen _f_a_c_t_o_r ImageMagick Last change: 19 Feb 1995 14 convert(1) User Commands convert(1) sharpen an image. Specify _f_a_c_t_o_r as the percent enhancement (0.0 - 99.9%). -shear <_x _d_e_g_r_e_e_s>_x<_y _d_e_g_r_e_e_s> shear the image along the X or Y axis by a positive or negative shear angle. Shearing slides one edge of an image along the X or Y axis, creating a parallelogram. An X direction shear slides an edge along the X axis, while a Y direction shear slides an edge along the Y axis. The amount of the shear is controlled by a shear angle. For X direc- tion shears, _x _d_e_g_r_e_e_s is measured relative to the Y axis, and similarly, for Y direction shears _y _d_e_g_r_e_e_s is measured relative to the X axis. Empty triangles left over from shearing the image are filled with the color defined as bordercolor (class borderColor). See X(1) for details. -size <_w_i_d_t_h>{%}_x<_h_e_i_g_h_t>{%}+<_o_f_f_s_e_t> width and height of the image. Use this option to specify the width and height of raw images whose dimensions are unknown such as GRAY, RGB, or CMYK. In addition to width and height, use -size to skip any header information in the image or tell the number of colors in a MAP image file, (e.g. -size 640x512+256). For Photo CD images, choose from these sizes: 192x128 384x256 768x512 1536x1024 3072x2048 Finally, use this option to choose a particular resolu- tion layer of a JBIG image (e.g. -size 1024x768). -solarize _f_a_c_t_o_r negate all pixels above the threshold level. Specify _f_a_c_t_o_r as the percent threshold of the intensity (0 - 99.9%). This option produces a solarization effect seen when exposing a photographic film to light during the development process. -spread _a_m_o_u_n_t displace image pixels by a random amount. ImageMagick Last change: 19 Feb 1995 15 convert(1) User Commands convert(1) _A_m_o_u_n_t defines the size of the neighborhood around each pixel to choose a candidate pixel to swap. -swirl _d_e_g_r_e_e_s swirl image pixels about the center. _D_e_g_r_e_e_s defines the tightness of the swirl. -texture _f_i_l_e_n_a_m_e name of texture to tile onto the image background. -transparency _c_o_l_o_r make this color transparent within the image. -treedepth _v_a_l_u_e Normally, this integer value is zero or one. A zero or one tells convert to choose a optimal tree depth for the color reduction algorithm. An optimal depth generally allows the best representa- tion of the source image with the fastest computational speed and the least amount of memory. However, the default depth is inappropriate for some images. To assure the best representation, try values between 2 and 8 for this parameter. Refer to quantize(9) for more details. The -colors option is required for this option to take effect. -undercolor <_u_n_d_e_r_c_o_l_o_r _f_a_c_t_o_r>_x<_b_l_a_c_k-_g_e_n_e_r_a_t_i_o_n _f_a_c_t_o_r> control undercolor removal and black generation on CMYK images. This option enables you to perform undercolor removal and black generation on CMYK images-- images to be printed on a four-color printing system. You can con- trol how much cyan, magenta, and yellow to remove from your image and how much black to add to it. The stan- dard undercolor removal is 1.0x1.0. You'll frequently get better results, though, if the percentage of black you add to your image is slightly higher than the per- centage of C, M, and Y you remove from it. For example you might try 0.5x0.7. -verbose print detailed information about the image. This information is printed: image scene number; image name; converted image name; image size; the image class (_D_i_r_e_c_t_C_l_a_s_s or _P_s_e_u_d_o_C_l_a_s_s); the total number of unique colors; and the number of seconds to read ImageMagick Last change: 19 Feb 1995 16 convert(1) User Commands convert(1) and convert the image. Options are processed in command line order. Any option you specify on the command line remains in effect until it is explicitly changed by specifying the option again with a different effect. Change '-' to '+' in any option above to reverse its effect. For example, specify +matte to store the image without its matte channel. By default, the image format is determined by its magic number. To specify a particular image format, precede the filename with an image format name and a colon (i.e. ps:image) or specify the image type as the filename suffix (i.e. image.ps). See DESCRIPTION for a list of valid for- mats. When you specify X as your image type, the filename has spe- cial meaning. It specifies an X window by id, name, or root. If no filename is specified, the window is selected by clicking the mouse in the desired window. Specify _i_n_p_u_t__f_i_l_e as - for standard input, _o_u_t_p_u_t__f_i_l_e as - for standard output. If _i_n_p_u_t__f_i_l_e has the extension .Z or .gz, the file is uncompressed with uncompress or gunzip respectively. If _o_u_t_p_u_t__f_i_l_e has the extension .Z or .gz, the file size is compressed using with compress or gzip respectively. Finally, precede the image file name with | to pipe to or from a system command. Use an optional index enclosed in brackets after a file name to specify a desired subimage of a multi-resolution image format like Photo CD (e.g. img0001.pcd[4]) or a range for MPEG images (e.g. video.mpg[50-75]). A subimage specifica- tion can be disjoint (e.g. image.tiff[2,4,7]). For raw images, specify a subimage with a geometry (e.g. -size 640x512 image.rgb[320x256+50+50]). Single images are written with the filename you specify. However, multi-part images (e.g. a multi-page Postscript document with +adjoin specified) are written with the filename followed by a period (.) and the scene number. You can change this behavior by embedding a printf format specification in the file name. For example, image%02d.miff converts files image00.miff, image01.miff, etc. IMAGE SEGMENTATION Use -segment to segment an image by analyzing the histograms ImageMagick Last change: 19 Feb 1995 17 convert(1) User Commands convert(1) of the color components and identifying units that are homo- geneous with the fuzzy c-means technique. The scale-space filter analyzes the histograms of the three color components of the image and identifies a set of classes. The extents of each class is used to coarsely segment the image with thresholding. The color associated with each class is determined by the mean color of all pixels within the extents of a particular class. Finally, any unclassified pixels are assigned to the closest class with the fuzzy c- means technique. The fuzzy c-Means algorithm can be summarized as follows: o Build a histogram, one for each color component of the image. o For each histogram, successively apply the scale- space filter and build an interval tree of zero cross- ings in the second derivative at each scale. Analyze this scale-space ``fingerprint'' to determine which peaks or valleys in the histogram are most predominant. o The fingerprint defines intervals on the axis of the histogram. Each interval contains either a minima or a maxima in the original signal. If each color component lies within the maxima interval, that pixel is con- sidered ``classified'' and is assigned an unique class number. o Any pixel that fails to be classified in the above thresholding pass is classified using the fuzzy c-Means technique. It is assigned to one of the classes discovered in the histogram analysis phase. The fuzzy c-Means technique attempts to cluster a pixel by finding the local minima of the generalized within group sum of squared error objective function. A pixel is assigned to the closest class of which the fuzzy membership has a max- imum value. For additional information see Young Won Lim, Sang Uk Lee, "On The Color Image Segmen- tation Algorithm Based on the Thresholding and the Fuzzy c-Means Techniques", Pattern Recognition, Volume 23, Number 9, pages 935-952, 1990. ENVIRONMENT DISPLAY To get the default host, display number, and screen. ImageMagick Last change: 19 Feb 1995 18 convert(1) User Commands convert(1) SEE ALSO display(1), animate(1), import(1), montage(1), mogrify(1), combine(1), xtp(1) COPYRIGHT Copyright 1996 E. I. du Pont de Nemours and Company Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting docu- mentation, and that the name of E. I. du Pont de Nemours and Company not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. E. I. du Pont de Nemours and Company makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. E. I. du Pont de Nemours and Company disclaims all warran- ties with regard to this software, including all implied warranties of merchantability and fitness, in no event shall E. I. du Pont de Nemours and Company be liable for any spe- cial, indirect or consequential damages or any damages what- soever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortuous action, arising out of or in connection with the use or per- formance of this software. AUTHORS John Cristy, E.I. du Pont De Nemours and Company Incor- porated ImageMagick Last change: 19 Feb 1995 19