Automatic image sharpening in an electronic imaging system
First Claim
1. A method for sharpening images captured by an imaging device having an electronic imager and subsequently reproduced in a reproduction device, both imaging and reproduction devices having respective spatial response functions, said method comprising the steps of:
- storing the imaging device spatial response function;
storing the reproduction device spatial response function;
capturing an image with the imaging device;
generating a system spatial response function from the imaging device spatial response function and the reproduction device spatial response function;
generating a sharpening filter function from the system spatial response function; and
applying the sharpening filter function to the image captured by the imaging device in order to sharpen the image.
4 Assignments
0 Petitions
Accused Products
Abstract
Digital reproductions of any size made from images scanned from film or taken by an electronic camera are optimally sharpened in a system-wide operation. The images are captured by an imaging device having an electronic imager and subsequently reproduced in a reproduction device, both imaging and reproduction devices having respective modulation transfer functions. Initially, the imaging device modulation transfer function and the reproduction device modulation transfer function are stored in separate devices. After an image is captured with the imaging device, a system modulation transfer function is generated from the imaging device modulation transfer function and the reproduction device modulation transfer function. Then a sharpening function is generated from the system modulation transfer function and the sharpening filter function is applied to the image captured by the imaging device in order to sharpen the image.
187 Citations
51 Claims
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1. A method for sharpening images captured by an imaging device having an electronic imager and subsequently reproduced in a reproduction device, both imaging and reproduction devices having respective spatial response functions, said method comprising the steps of:
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storing the imaging device spatial response function; storing the reproduction device spatial response function; capturing an image with the imaging device; generating a system spatial response function from the imaging device spatial response function and the reproduction device spatial response function; generating a sharpening filter function from the system spatial response function; and applying the sharpening filter function to the image captured by the imaging device in order to sharpen the image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 50)
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20. A method for sharpening images captured by a imaging device having an electronic imager and subsequently reproduced in a reproduction device, both imaging and reproduction devices having respective modulation transfer functions, said method comprising the steps of:
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characterizing the modulation transfer function of the imaging device relative to a sampling frequency of the imager; storing the imaging device modulation transfer function with the imaging device; characterizing the modulation transfer function of the reproduction device relative to a sampling frequency of the reproduction device; storing the reproduction device modulation transfer function with the reproduction device; capturing an image with the imaging device; selecting a reproduction size; scaling the imaging device modulation transfer function for the selected reproduction size; generating a system modulation transfer function from the imaging device modulation transfer function and the reproduction device modulation transfer function; generating a sharpening function from the system modulation transfer function; and applying the sharpening filter function to the image captured by the imaging device in order to sharpen the image. - View Dependent Claims (21, 22, 23, 24, 25)
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26. An electronic imaging system for capturing, processing, and reproducing images, both capturing and reproducing functions characterized by respective modulation transfer functions, said system comprising:
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an electronic imaging device including an imager for capturing the images, said imaging device having an imaging device modulation transfer function and a storage device for storing data representing the imaging device modulation transfer function; a reproduction device for reproducing the image captured by the imaging device, said reproduction device having a reproduction device modulation transfer function and a storage device for storing data representing the reproduction device modulation transfer function; and a processor for processing the images captured by the imaging device before they are reproduced by the reproduction device;
said processor including means for generating a system modulation transfer function from the imaging device modulation transfer function and the reproduction device modulation transfer function, means for generating a sharpening filter function from the system modulation transfer function, and means for applying the sharpening filter function to the images captured by the imaging device in order to sharpen the images. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An imaging device for capturing images and supplying the captured images to a computer, said imaging device comprising:
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an image sensor positioned in the imaging device for capturing an image; an optical section for focusing image light from the image upon the image sensor; a sensor driver for driving the image sensor at a predetermined sampling frequency in order to generate image data; a memory for storing MTF data representing a modulation transfer function of the image sensor characterized relative to the predetermined sampling frequency of the image sensor; and a processor for generating an imaging device output signal comprised of the image data and the MTF data, whereby the imaging device output signal is made available to the computer. - View Dependent Claims (38, 39)
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40. A reproduction device for reproducing images supplied by a computer, said reproduction device comprising:
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a memory for storing MTF data representing a modulation transfer function of the reproduction device; an interface for outputting the MTF data to the computer where it is used to generate sharpened images; a processor for generating a reproduction signal from the sharpened images; and an output generator for generating reproductions of the sharpened images. - View Dependent Claims (41, 42)
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43. An imaging kit for capturing images and supplying the captured images to a computer, said imaging kit comprising:
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an imaging device including an image sensor for capturing an image, an optical section for focusing image light from the image upon the image sensor, a sensor driver for driving the image sensor at a predetermined sampling frequency in order to generate image data, and a processor for generating an imaging device output signal comprised of the image data; and a computer file including a memory for storing MTF data representing a modulation transfer function of the image sensor characterized relative to the predetermined sampling frequency of the image sensor, whereby the imaging device output signal and the computer file is made available to the computer for sharpening the images. - View Dependent Claims (44, 45, 46)
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47. A method for enabling the sharpening of images from a digital capture device comprising the steps of:
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capturing an image of a test chart incorporating features for measuring the modulation transfer function (MTF) of the capture device; generating test chart image data; analyzing the test chart image data to determine the capture device MTF; and providing the MTF data along with the capture device so that subsequently captured images may be sharpened. - View Dependent Claims (48, 49)
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51. A reproduction device for reproducing images captured by an imaging device, said reproduction device comprising:
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a memory for storing reproduction MTF data representing a modulation transfer function of the reproduction device; an interface for inputting imaging MTF data representing a modulation transfer function of the imaging device; a processor for generating a system modulation transfer function from the imaging MTF data and the reproduction MTF data and a sharpening filter function from the system modulation transfer function; means for applying the sharpening filter function to the images captured by the imaging device to generate sharpened images; and an output generator for generating reproductions of the sharpened images.
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Specification