Abstract: A predetermined number of sections of an original corresponding to a predetermined number of halftone dot sub-cells are scanned to generate an image signal for each section. If the image signal for a given section is greater than a highlight level reference value (Hi), the corresponding halftone dot sub-cell is made one of two colors, black or white. If the image signal for the given section is less than a shadow level reference value (S), the corresponding halftone dot sub-cell is made the other of the two colors, white or black. If the image signal for the given section falls between the highlight and shadow level reference values, it is compared witha value (Y) representing the average density of the predetermined number of sections of the original to determine whether the corresponding halftone dot sub-cell should be made black or white.

Abstract: In reproducing an image, partial distortion (especially partial enlargement) is performed on desired portions of the image according to magnification data for the desired portions determined by a means for determining magnification ratio along any of the dimensions of the image.

Abstract: The resolution of an array sensor can be increased by projecting images of picture elements, which lie on the same scanning line, on a plurality of one-dimensional array sensors composed of a number of photoelectric transducers arranged with an equal interval in a row; and then subjecting picture signals, which have been output respectively from the array sensors, to a combination processing so as to obtain continuous picture signals. It is possible, without using any memory unit, to output picture signals with a resolution higher than that available from the use of a single one-dimensional array sensor, namely, with a resolution proportional to the number of a plurality of one-dimensional array sensors.

Abstract: In reproducing images, number of the pixels on one scanning line of an original picture is made to correspond to number of the addresses of a memory to increase use efficiency of the memory as well as to improve the detail of reproduction images.