Abstract: A color correction method applicable to a digital processing type of color copier, whereby a set of color patches of respectively different sample colors is printed using a set of printing data values, the color patches are then scanned and analyzed to obtain color patch input data values by the color copier, and each of all of the possible input color data values that can be produced by the scanner/analyzer section of the color copier is then related to one of the color patch input data values which is closest thereto in a 3-dimensional color space. Each of these possible input color data values is thereby related to an appropriate color printing value, whereby a color correction table can be generated which provides correction accuracy that is independent of non-linearity of color printing characteristics.

Abstract: An image signal processing apparatus for converting input signal values representing density levels of successive picture elements of an image to corresponding bi-level signal values, whereby a conversion error for an object picture element is apportioned among a set of unprocessed adjacent picture elements, to update respective values of accumulated error. Each input signal value is compensated, prior to conversion, by a value derived from the total accumulated errors of the object picture element and these adjacent picture elements, while the conversion error is derived by subtracting from the bi-level output value a value obtained by compensating the input signal by the accumulated error for the object picture element.

Abstract: An image signal processing circuit for converting step-gradation density values (I.sub.xy) of successive picture elements to bi-level values (P.sub.xy) for display by a bi-level display device, in which a bi-level error (E.sub.xy) between a bi-level value determined for a picture element and an appropriate density value for the element is apportioned among a set of peripherally adjacent picture elements (A to D) by computing a corresponding set of error apportionment values (G.sub.A to G.sub.D), and in which a difference between the sum total of these apportionment values and the bi-level error is derived, and error apportionment is modified such as to eliminate the effects of this difference. Improved reproduction is thereby attained of image regions which are of uniformly high density or low density.

Abstract: An image signal processing circuit for converting a continuous tone image signal to a bi-level image signal, for producing a spatial gray scale image on a bi-level display device such as a gas plasma display panel. Respective values of apportionment factors (K.sub.A to K.sub.D) used for apportioning a bi-level conversion error of each picture element of the image among a plurality of picuture elements (A to D) positioned peripehrally adjacent thereto are periodically altered, in a periodic or random succession of values, to thereby effectively eliminate the generation of a texture pattern in display regions corresponding to areas of uniform density in the original image.

Abstract: The invention relates to a method for processing an image signal such that areas of original image data are sequentially scanned with a scanning window having a size corresponding to M picture elements in units of a predetermined number of picture elements so as to perform halftone display in accordance with black-and-white binary distribution with respect to the signal levels of the picture elements within the scanning window every time the scanning window is moved. The picture elements within the scanning window are assigned an order of preference in accordance with their image signal levels. A sum of the image signal levels of the picture elements within the scanning window is calculated, and A and N of the equations S=C.times.N+A are calculated, where C is a predetermined image signal level (e.g., black level and maximum level), N is an integer, and A is the image signal level falling within the range O.ltoreq.A<C.

Abstract: A device comprising a support member of a solid material, a liquid material in intimate contact with and supported by the support member and an electrical means for creating an electric field having an electric vector in a direction parallel to the interface between the two materials to cause an electroosmotic movement of a portion of the liquid material and a resulting patterned unevenness of the configuration of the liquid material, wherein the liquid material contains a derivative of silane or siloxane which has a functional group having chemical affinity with solid organic materials useful as the support member, typified by vinyl, methacryloxy, cycloepoxy, mercapto and chlorine radicals, and/or another functional group having chemical affinity with inorganic materials useful as the support member, typified by alkoxyl group. When the solid and liquid materials are transparent, the device functions as an electrically controllable optical lens.