Abstract: A multiple image scanner that performs a single scan of a document containing different types of images (e.g., text and graphics) and sends multiple renditions of the same document from the scanner to a host computer (e.g., one high resolution gray scale image and one low resolution high bit depth color image; or one high resolution, low bit depth gray scale or monochrome image and one low resolution, high bit depth gray scale or monochrome image; or one high resolution, low bit depth color image and one low resolution, high bit depth color image), thus greatly reducing the total amount of data sent to and processed by the host computer.

Abstract: Method and apparatus for controlling a computer bus having first and second bus slots and operable with a bus controller at first and second data transfer rates. When the computer bus is operating at the first data transfer rate, the bus is partitioned so that the address/data pins of the bus controller are coupled to the address/data pins of both of the first and second bus slots, and the control pins of the bus controller are coupled only to the control pins of the second bus slot. When the computer bus is operating at the second data transfer rate, the bus is partitioned so that the address/data pins of the bus controller are coupled only to the address/data pins of the first bus slot, and the control pins of the bus controller are coupled only to the control pins of the first bus slot. The second data transfer rate may be faster than the first data transfer rate.

Abstract: An image capture system comprising a scanner having a 10-bit analog-to-digital converter. The scanner operates within an environment that includes a host computer that is configured to accept 8-bit data. The contrast enhancement of the scanner is improved by applying an improved tonal adjustment on a scanned image. The host computer connected to the scanner provides an 256-value to 256-value look-up table (i.e., the 8-bit tone map) to the scanner. The scanner generates an interpolated 1024-level to 256-level look-up table (i.e., a 10-bit tone map) from the 256-level to 256-level look-up table. The 1024-value to 256-value look-up table is generated by using linear interpolation and extrapolation. The scanner can thus provide better contrast enhancements without having to modify the software running on the host computer.

Abstract: A method for dynamically determining and adjusting the color balance of the light strip along one edge of the scanned area and adjusting the gains of independently controlled red, green and blue channels of a CCD array. Alternatively, the gain of one color channel may be held constant and measured to determine the light intensity of the light source as the temperature of the light source varies. The power to the light is then changed to maintain the intensity of the light source within a predetermined range. The three color channels are then compared to a predetermined color balance. If the color balance is outside of a predetermined range, the other two color channels gains are varied in order to maintain the color balance between the three color channels.

Abstract: An image processing method for converting an input matrix into an output matrix including steps of calculating an increment value and a target value based upon the resolution of the input matrix and the resolution of the output matrix. As each picture element of the input matrix is received the increment value is added to the value of a counter. When the value of the counter is greater than the target value, the received picture element is placed into the output matrix and the target value is subtracted from the value of the counter.

Abstract: A method of determining an exposure time for a photosensor based on a desired resolution along a scan direction and a desired resolution in a cross direction may comprise the steps of determining an initial exposure time based on the desired resolution in the cross direction; determining a minimum resolution in the scan direction based on the initial exposure time; comparing the minimum resolution in the scan direction to the desired resolution in the scan direction; and increasing the initial exposure time if the minimum resolution in the scan direction is greater than the desired resolution in the scan direction.

Abstract: A system and method for improving the signal to noise ratio of a CCD sensor within an optical scanner varies the exposure time of the CCD sensor. Exposure time is varied by clocking the CCD sensor a number of times equal to the number of pixels in the CCD sensor plus an additional number of clock cycles to create a delay. The additional exposure time maximizes the magnitudes of the charges produced by the CCD sensor. The required delay is computed during a pre-scan calibration step.

Abstract: The present invention improves the scanning speed (i.e., the line exposure time) of an image scanner that is operated at a lower than normal resolution. The image scanner contains a charge coupled device (CCD) that stores a plurality of pixel charges. Before digitizing the pixel charges, the present invention combines two or more of these pixel charges. Thus, the effective resolution of the CCD can be divided by a designated amount, thus reducing processing time and keeping signal levels nearly constant.

Abstract: A photosensor device which comprises a first photosensor array having a first predetermined number of pixels for generating a first data signal indicative of a first color component image of an object which is imaged thereon; a second photosensor array having a second predetermined number of pixels for generating a second data signal indicative of a second color component image of the object which is imaged thereon; and color registration error correction means operatively associated with the photosensor array for correcting color registration error due to a predetermined difference in image size between the first color component image and the second color component image.

Abstract: An image scanning system for producing digital data of a predetermined resolution representing a scanned image of an original. The system includes a photosensing array for generating the digital data, a stepper motor having steps of predetermined size for positioning the array with respect to the original, an image buffer for storing the data and control system for synchronizing the scanning and the storing of data at one or more Y-positioning speeds. Scan line extents along the Y-direction are defined by the relationship of the Y-positioning speed to the array exposure time. The scan lines in conjunction with the present invention have boundaries, wherein the boundaries can occur on or between said motor steps.

Abstract: A single pass color optical scanner which produces multiple color component images of a scan line region of a document at different times, but which is nevertheless capable of selective scaling of image data through adjustment of scanning speed.

Abstract: In a document scanner that is operating in the binary mode, the magnitude of the signal that is generated for each picture element (PEL) of each document scan line is compared to the magnitude of a threshold signal. Either a binary 0 or a binary 1 is generated as a result of this comparison. The threshold signal magnitude is dynamically established by a method and an apparatus that provides a stored history or histogram of the various signal magnitudes that are generated for each PEL of a plurality of the document scan lines. Since the signal magnitude(s) that is provided by scanning the background, non-image, area of the document occurs the majority of the time within this histogram, the magnitude of this majority signal(s) is used to set the threshold signal magnitude. As a result, the PELS of the document's visible image are converted to a binary electronic image with a minimum loss of visual image content.

Abstract: An image processor for converting an input matrix of input pixels into an output matrix of output pixels, where the number of input pixels differs from the number of output pixels. From the input matrix, the image processor generates an intermediate resolution matrix. The number of pixels in a particular dimension of the intermediate resolution matrix is an integer multiple of the desired number of output pixels in the same dimension. This enables the image processor to select from the intermediate resolution matrix output pixels which are evenly space from one another in the same dimension.