Abstract: A data compressing technique and a data decompressing technique provide a compressing dictionary storing unit for storing a compressing dictionary usable when data to be compressed is compressed, a compressing dictionary use or non-use deciding unit for deciding whether the compressing dictionary is to be used or not when the data to be compressed is compressed, and a coding unit for coding the data to be compressed on the basis of the compressing dictionary when the compressing dictionary use or non-use deciding unit decides the compressing dictionary is to be used, whereas not coding but outputting the data to be compressed when the compressing dictionary use or non-use deciding unit decides the compressing dictionary is not to be used, thereby stably achieving a preferable compression ratio for a small quantity of data such as text data in a text file or the like, besides achieving a high compression ratio for a data having different statistics.

Abstract: A data compressing/decompressing apparatus is suitable for compressing data containing plural-byte characters, for instance, a Japanese language text. The data compressing/decompressing apparatus owns a homonym dictionary in which KANJI-character idioms, KANJI-character-reading, and homonym discrimination information are stored in correspondence with each other. This data compressing/decompressing apparatus converts a KANJI-character idiom contained in declarative sentence data into phonetic data, and further compresses this phonetic data to output the compressed phonetic data. The phonetic data is such data that this KANJI-character idiom is replaced by information constituted by character number discrimination information indicative of the character number about KANJI-character idiom reading, the reading thereof, and the homonym discrimination information thereof.

Abstract: In an image and code data compression apparatus for compressing the image data and further compressing the code data which are compressed from the image data, the apparatus includes: a dividing unit for receiving the image data and dividing them into a plurality of image data blocks; a transformation unit operatively connected to the dividing unit for performing an orthogonal transformation to the image data block and calculating transformation coefficients for every frequency component; a quantizing unit operatively connected to the transformation unit for quantizing the transformation coefficients which are calculated by the transformation unit by using a quantized threshold value which is set commonly to all image data, and calculating the quantized orthogonal transformation coefficients; a coding unit operatively connected to the quantizing unit for performing the variable length coding process for the quantized transformation coefficients which are calculated by the quantizing unit and outputting the cod

Abstract: A heads-up display including a holographic optical element which reflects only at least one specific wavelength and allows a background light of other wavelengths to pass therethrough, an information source which emits information light having the specific wavelength, and a device for removing a wavelength of light corresponding to a complementary color of the specific wavelength.