NOT2INTR 1D 02 April 2001 NIST NFIS Reference Manual not2intr converts an image comprised of non-interleaved color component planes to an image with interleaved color component pixels. not2intr <outext><imagefile><w,h,d, ppi > -raw_out -YCbCr H0,V0:H1,V1:H2,V2 Not2intr takes as input a raw pixmap file containing an uncompressed image comprised of non-interleaved color component planes and converts the image to interleaved color component pixels. This utility requires there be three color components in the input image. Two output file formats are possible, a NIST IHead file (the default) or a raw pixmap file (specified by the -raw_out option). For example, the pixels of an RGB color image are interleaved when a pixel's R, G, and B components are sequentially adjacent in the image byte stream, ie. RGBRGBRGB... . If the color components are non-interleaved, then all (R)ed components in the image are sequentially adjacent in the image byte stream, followed by all (G)reen components, and then lastly followed by all (B)lue components. Each complete sequence of color components is called a plane. The utility intr2not converts interleaved to non-interleaved color components. It is possible that the component planes of an input YCbCr image have been previously downsampled. If so, the -YCbCr flag must be included on the command line, listing the appropriate component plane downsampling factors. By default, this utility assumes no downsampling. YCbCr image results should always be explicitly stored in a raw pixmap file, because the IHead format only supports RGB pixels. (See YCbCr OPTIONS below.) All switch names may be abbreviated; for example, -raw_out may be written -r. <outext> the extension of the output file. To construct the output filename, not2intr takes the input filename and replaces its extension with the one specified here. <image file> the input raw pixmap file containing the color image to be converted. <w,h,d,[ppi]> the attributes of the input image in the raw pixmap file. w the pixel width of the pixmap h the pixel height of the pixmap d the pixel depth of the pixmap ppi the optional scan resolution of the image in integer units of pixels per inch. -raw_out specifies that the results should be stored to a raw pixmap file. -YCbCr H0,V0:H1,V1:H2,V2 indicates that a YCbCr color image is being input whose component planes have been previously downsampled. The -raw_out flag should always be used in conjunction with this option. (See YCbCr Options below.) A common compression technique for YCbCr images is to downsample the Cb & Cr component planes. Not2intr can handle a limited range of YCbCr downsampling schemes that are represented by a list of component plane factors. These factors together represent downsampling ratios relative to each other. The comma-separated list of factor pairs correspond to the Y, Cb, and Cr component planes respectively. The first value in a factor pair represents the downsampling of that particular component plane in the X-dimension, while the second represents the Y-dimension. Compression ratios for a particular component plane are calculated by dividing the maximum component factors in the list by the current component's factors. These integer factors are limited between 1 and 4. H,V factors all set to 1 represent no downsampling. For complete details, not2intr implements the downsampling and interleaving schemes described in the following reference: W.B. Pennebaker and J.L. Mitchell, "JPEG: Still Image Compression Standard," Appendix A - "ISO DIS 10918-1 Requirements and Guidelines," Van Nostrand Reinhold, NY, 1993, pp. A1-A4. For example the option specification: -YCbCr 4,4:2,2:1,1 indicates that there has been no downsampling of the Y component plane (4,4 are the largest X and Y factors listed); the Cb component plane has been downsampled in X and Y by a factor of 2 (maximum factors 4 divided by current factors 2); and the Cr component plane has been downsampled in X and Y by a factor of 4 (maximum factors 4 divided by current factors 1). Note that downsampling component planes is a form of lossy compression. The utility rgb2ycc converts RGB pixmaps to the YCbCr colorspace, and it conducts downsampling of the resulting YCbCr component planes upon request. From test/imgtools/execs/not2intr/not2intr.src: % not2intr raw face.nin 768,1024,24 -r converts the non-interleaved RGB face image in a raw pixmap file into interleaved color pixels. intr2not(1D), rgb2ycc(1D) NIST/ITL/DIV894/Image Group