Abstract: A variable resolution color scanner comprising multiple color line sensors arranged substantially in parallel and at a mutual distance. The scanner is capable of providing color components that are combined by means of delays and interpolators in order to form a high precision color representation of a scanned original. The color components are combined electronically such that at least one of the color components represent(s) an actually imaged line on the original, and such that the other color components represent estimated lines. Alternatively, the color components are combined electronically such that all other color components represent estimated lines.

Abstract: An optical scanner having a weighted adaptive threshold value determination for generating a one-bit representation of a scanned original. The optical scanner comprises an optical detecting unit which provides a discrete signal representing pixels in a scanned region and first device for generating a first weighted discrete signal which is a weighted version of the discrete signal representing pixels in a scanned region. The optical scanner further comprises second device for providing a filtered signal which is a filtered version of the weighted discrete signal and third device for generating a second weighted signal, being a weighted version of the filtered signal. A comparison device produces a binary output as a function of the discrete signal representing pixels in a scanned region and the second weighted signal.

Abstract: A method and apparatus of preparing the reproduction of a document based on scanning the original including generating a signal representing grey tone values for points along lines across the scanned original and providing a set of threshold values for said points. The set of threshold values being determined so that grey tone values in a uniform area on the original are converted into a uniform black or white representation in a first one-bit representation. The method and apparatus provides parameter values for said points in a dither circuit, and converts the grey tone signal received from the line scanning unit into a signal comprising a second one-bit representation. The conversion into a one-bit representation is performed by depending on the individual grey tone values compared with the present threshold values and the dither circuit output for the points in question.

Abstract: An optical scanner with variable line resolution, said scanner collecting information from an original along lines with a predetermined mutual spacing. A calculating unit calculates the location of lines with desired resolution with respect to the scanned lines in response to a desired resolution. A line detector registers optical information along lines on the original and supplies a signal representing the registered, optical information. The information signal is branched along two branches in a branch means. A delay is coupled in one of said branches and is adapted to delay the information signal passing in the branch for a period of time corresponding to a line length in said information signal. An interpolation means receives the information signals from said branches and forms as a desired line an interpolation signal between information signals in response to the location of the desired line with respect to the location of the scanned lines.

Abstract: An optical scanner having a variable resolution wherein an optical detecting unit controlled by a pixel clock signal generates a discrete signal representing pixels scanned in a region. An analog-to-digital converter converts the signal to a digital signal with a preselected resolution controlled by a sample clock generator. The sample clock generator receives the pixel clock signal, and through a counter and a store, operates an addressed, binary data word which is sent to a register. The register is coupled to a further periodic clock generator that controls reading from the register and provides a clock signal with pulses when the bits of the data word assume a first binary state, and no pulses when the bits assume a second binary state. The clock signal is passed to the analog-to-digital converter as a sample clock signal.

Abstract: A digital data representation of an original entered by optical scanning is provided by generating a data signal having grey-level values for points on a scanning line transversely to the original in the scanning. Then local threshold values of zones on the original are determined. These local threshold values are determined statistically in response to the frequency distribution of grey-level values belonging to points from line segments in the zone. The grey-level value frequency distribution of the zones is updated currently, segments from the line last scanned replacing the oldest line segments in the zones, whereby the frequency distribution is changed and updated threshold values are determined. The grey-level value of a point is compared with the updated threshold value of the zone concerned to determine a state of the point in the digital data representation, and the states of the individual points are stored to provide the digital data representation.