Color image array scanner with high resolution monochrome mode
First Claim
1. Solid-state scanning apparatus for scanning color and monochromatic images and operable in color mode for color scanning at a first pixel resolution and operable in a mono mode for monochromatic scanning at a second pixel resolution, said apparatus comprises:
- an array of pixel photosensors, with each photosensor most sensitive to a predetermined color of light;
addressing means for addressing pixel photosensors in the array; and
scaling means, responsive to said addressing means, for scaling each photosensor pixel signal to compensate for light intensity loss of the addressed pixel photosensor.
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Abstract
A solid-state array scanner with a color filter at each pixel sensor is provided to accomplish color scanning of color images with a set of pixels sensors for each color pixel. In addition, a scaler device is provided for selectively scaling the output pixel signal from each pixel sensor to correct for color filter loss when scanning black/white images. Thus, while a set of pixel signals must be combined for each color pixel in color mode scanning, in mono mode scanning of black/white images, the pixel signal from each pixel signal may be used. An address means selectively addresses each solid-state pixel sensor device in the array for readout of the illumination intensity, or pixel signal, sensed by that device. Each pixel sensor will have a given color filter dependent upon the sensor'"'"'s location in the array. From the address of the pixel sensor, the scaler value to compensate for the color filter in mono mode can be selected. The scaling compensation can be accomplished by changing the reference voltage used in an analog-to-digital (A/D) converter that converts the pixel signals from the analog array output of the pixel sensors to digital values. Alternatively, the scaling compensation can be accomplished by multiplying a digital scaling factor times the pixel digital intensity value from each pixel sensor. Also, the scaling compensation can be accomplished by a programmed digital signal processor.
40 Citations
18 Claims
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1. Solid-state scanning apparatus for scanning color and monochromatic images and operable in color mode for color scanning at a first pixel resolution and operable in a mono mode for monochromatic scanning at a second pixel resolution, said apparatus comprises:
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an array of pixel photosensors, with each photosensor most sensitive to a predetermined color of light; addressing means for addressing pixel photosensors in the array; and scaling means, responsive to said addressing means, for scaling each photosensor pixel signal to compensate for light intensity loss of the addressed pixel photosensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Solid-state scanning apparatus for scanning color and monochromatic images and operable in color mode for color scanning at a first pixel resolution combining color signals from a color space set of pixel photosensors and operable in a mono mode for monochromatic scanning at a second pixel resolution with a monochromatic pixel signal for each distinct pixel photosensor, said apparatus comprises:
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an array of pixel photosensors with each photosensor most sensitive to a predetermined color of light in the color space set and having a predetermined light intensity loss for white light; addressing means for addressing each pixel photosensor in the array; means for producing a pixel light intensity signal for each pixel photosensor addressed by said addressing means; and scaling means in the mono mode responsive to said addressing means, said scaling means for scaling each pixel signal to compensate for the predetermined light intensity loss of the addressed pixel photosensor whereby a monochromatic pixel signal is produced for each pixel photosensor when scanning monochromatic images. - View Dependent Claims (12, 13)
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14. An array scanner for scanning color images in a color scanning mode and for scanning black/white images in a mono (black/white) mode, said array scanner having a matrix of photosensor circuits, each photosensor having a color filter, a method for producing a monochromatic signal corrected for white light illumination when the array scanner is in the mono mode, said method comprising the steps of:
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detecting the mono mode; in the mono mode, determining the color filter at each photosensor and a scaling factor for each color filter; and in the mono mode, scaling a color-filtered pixel signal from each photosensor with the scaling factor to produce a black/white pixel signal compensated for light loss of the color filter. - View Dependent Claims (15, 16, 17)
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18. Solid-state scanning apparatus for scanning color and monochromatic images and operable in color mode for color scanning at a first pixel resolution and operable in a mono mode for monochromatic scanning at a second pixel resolution, said apparatus comprises:
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a plurality of pixel photosensors comprising a color space set of photosensors whose output pixel signals when combined form a color pixel signal for the color space set of photosensors; addressing means for addressing the pixel photosensors; and scaling means, responsive to said addressing means, for scaling the output pixel signals when operable in the mono mode.
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Specification