Abstract: A multi-level image encoding/decoding apparatus, which performs bit modeling processing on coefficients, which are the result of wavelet transform of a multi-level image read out from a transform coefficient storage memory, by accessing a significance information memory, a plus/minus sign memory, a processed information memory and a refinement information memory, includes an address generator for generating an address for accessing the processed information memory and the refinement information memory and an address generator for generating an address for accessing the significance information memory and the plus/minus sign memory.

Abstract: A multi-level image encoding/decoding apparatus, which performs bit modeling processing on coefficients, which are the result of wavelet transform of a multi-level image read out from a transform coefficient storage memory, by accessing a significance information memory, a plus/minus sign memory, a processed information memory and a refinement information memory, includes an address generator for generating an address for accessing the processed information memory and the refinement information memory and an address generator for generating an address for accessing the significance information memory and the plus/minus sign memory.

Abstract: A plurality of channel data groups and a coupling data group are supplied to a data input port of a data buffering apparatus so as to be temporarily stored in a buffering memory having a first memory area assigned to a non-coupled channel data group, a second memory area assigned to a coupled channel data group and a third memory area assigned to the coupling data group, and the data buffering apparatus outputs the channel data group from the first memory area or the channel data group and the coupling data group from the second and third memory areas before the next channel data group arrives at the data input port so as to decrease the memory areas of the buffer memory.

Abstract: A triplet decoding method capable of decoding operation in a short time is provide, in which a triplet data Y is defined as Y=9M1+3M2+M3. A first decimal value -9 is subtracted from a decimal value Y to generate a first subtraction result. A second decimal value -18 is subtracted from the value of Y to generate a second subtraction result. A third decimal value -27 is subtracted from Y to generate a third subtraction result. Then, whether each of the first, second, and third subtraction results has a negative polarity is judged to know M1. A provisional triplet data Y' is calculated by subtracting 9M1 from Y. Further, the first value -9 is subtracted from a value of Y' to generate a fourth subtraction result. The second value -18 is subtracted from the value of Y' to generate a fifth subtraction result. The third value -27 is subtracted from the value of Y' to generate a sixth subtraction result.

Abstract: An image signal decoder including a DC component correction processing section which inputs inverse transformed DC data X as direct current components of IDCT signals and produces DC component correction data Yn for correcting the inverse transformed DC data X of a target block in process using stored DC components RD corresponding to adjacent blocks of a target block image, resulting in reducing block distortion noises of an decoded image of compressed codes to improve image quality on visual evaluation and to make a large capacity image memory for storing the decoded image disused.

Abstract: In an optical system, when a binary image is to be read, a first reducing projection lens is located onto an optical axis and focuses an image of the original at a first magnification (relatively high magnification), and a mirror divides the entire image into three divided images which will be then projected onto three CCDs, respectively. On the other hand, when a multivalued image is to be read, a second reducing projection lens is located onto the optical axis and focuses an image of the original at a second magnification (relatively low magnification) which is lower than the first magnification, and the entire image is projected onto one of the three CCDs.

Abstract: An apparatus for reproducing an image with a desired magnification other than that expressed in an integer comprises a key switch for inputting the desired magnification. When reproducing the image with the selected magnification, it is necessary to interpolate pixel dots by increasing or decreasing the number of pixel dots for each predetermined region. The pixel dots are output in accordance with interpolation tables.The image reproducing apparatus further comprises an interpolation table preparing device for preparing a plurality of interpolation tables having different positions for interpolating the pixel dots in each predetermined region in accordance with the desired magnification, and a switching device for switching among the plurality of interpolation tables at random for each scan line. Since the plurality of interpolation tables are switched for each scan line, no regular patterns appear on the reproduced images.