Image analysis – Image sensing – Multiple scanning
Reexamination Certificate
1998-12-17
2003-09-30
Boudreau, Leo (Department: 2621)
Image analysis
Image sensing
Multiple scanning
C382S312000, C235S462010
Reexamination Certificate
active
06628848
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to a technical field where image reading apparatuses are utilized for digital photoprinters for photoelectrically reading images recorded on films to obtain prints. (photographs) that are reproduced from the images.
Images recorded on photographic films (hereinafter called the films) such as negative films, reversal films and the like are mainly printed out on photosensitive material (photographic paper) by projecting the on-film image onto the photosensitive material so that the photosensitive material is subjected to surface exposure or so-called direct exposure (analog exposure).
On the other hand, printing apparatuses utilizing digital exposure have been put to practical use in recent years. More specifically, a digital photoprinter is used for printing out (finishing off) an image recorded on a film through the steps of reading the image photoelectrically, converting the read-out image into a digital signal, performing various kinds of image processing in order to obtain image data to be recorded and subjecting photosensitive material to scanning exposure by means of the recording light modulated according to the image data, to thereby record the image (latent image).
As exposure conditions at the time of printing can be determined by processing images with digital data as image data in the digital photoprinter, high-grade prints that have been unavailable until now become obtainable by such as making compensation for image fade-out and improper gradation such as washed-out highlight and dull shadow originating from backlight, electronic flashing and the like, sharpness processing, compensation for color or density failure. Moreover, a composite photograph using a plurality of images, image division, a composition of characters and the like can be attained by processing the image data. The image data processing also makes it possible to output edited/processed prints freely in accordance with an intended use.
Furthermore, the digital photoprinter makes image data applicable for other purposes than photography, since the photoprinter allows images to be outputted as prints (photographs) and also allows the image data to be not only supplied to a computer, for example, but also stored in, optical and/or magnetic recording media such as floppy disks.
Such a digital photoprinter as described above essentially comprises an image input apparatus having a scanner (image reading apparatus) for reading an image recorded on a film photoelectrically and an image-processing apparatus for subjecting the read-out image to image processing in order to provide output image data (exposure conditions), and an image output apparatus having a printer (image recording apparatus) for recording a latent image by subjecting photosensitive material to scanning exposure according to the image data outputted from the image input apparatus and a processor (developing apparatus) for subjecting the exposed photosensitive material to developing processing for printing purposes.
The operation of the scanner includes making read light emitted from a light source incident on a film to obtain projected light for carrying an image projected on, the film, effecting image formation in an image sensor such as a charge coupled device (CCD) by means of an image forming lens so as to read the image by subjecting the projected light to photoelectric conversion, performing various kinds of image processing as the occasion demands and sending data concerning the on-film image (image data signal) to the image-processing apparatus.
The operation of the image-processing apparatus includes setting image processing conditions according to the image data read by the scanner, applying image processing corresponding to the set conditions to the image data and sending output image recording data (exposure conditions) to the printer.
The operation of the printer, that is, a printer utilizing light beam scanning exposure, for example, includes modulating a light beam according to the image data sent from the image-processing apparatus, deflecting the light beam in the main scanning direction, transporting the photosensitive material in an auxiliary scanning direction perpendicular to the main scanning direction in order to form a latent image by exposing (printing) the photosensitive material, using the tight beam that carries the image therewith and performing developing processing corresponding to the photosensitive material in the processor in order to make a print (photograph) reproduced from the on-film image.
As an image reading method at a digital photoprinter, a surface exposure method, in which first a read light is irradiated all over a frame of a film, and then the projected light is read through each of red (R), green (G), and blue (B), filters intercharged each other in order by an area sensor photoelectrically, is known in the art. Another method, i.e., a slit scanning method, in which first line sensors for respective reading of R, G, and B are used, and secondly a read light in a slit formed in parallel to the extending direction (main scanning direction) of the line sensors is incident on the film, and then the film is transported (or an optical system is moved) in the longitudinal direction of the film, or in the auxiliary scanning direction perpendicular to the main scanning direction, and finally whole area of the frame of the film is read by slit scanning, is also known in the art.
The surface exposure method and the slit scanning method each have advantages and disadvantages. An area sensor is generally high in cost, since it contains a number of photoelectric transducers, and CCD cells. Particularly, if a reproduction image of high quality is required, it is necessary to employ an area sensor containing a large number of cells equal to or proportional to the squared number of the resolution, in order to read the original image in higher resolution.
Moreover, an area sensor supplied in the market as a product sometimes contains a small number of defective cells, so-called defective pixel cells, which fail to output accurate signals in accordance with a quantity of the incident light. The area sensor including the defective pixel cells is often found among the area sensors which have been produced at a some high yield rate. This necessitates a complicated correction circuit to compensate errors caused by the defective cells including defective pixels.
As a result, reading by the slit scanning method is more advantageous from the standpoint of cost.
In order to obtain a reproduction image of high quality, which properly has reproduced an original image, in the case of reading the image by the scanner, it is necessary to read a whole density range of the original image with the highest possible resolution, and it is preferable to read with the widest possible dynamic range. In order to accomplish this, for example, when a photograph film is read out, a so-called density control is performed in such a way that the image reading is carried out under a condition that an image sensor is saturated at a density just equal to or merely lower than the lowest density of the original image on the photograph film.
Moreover, when one color occupies a large area of an image, like an image of a subject taken on a green of a golf course, or an image of a person's face taken in front of wall paper with a bright color, so-called color failure occurs so that a reproduction image comes out with unnatural colors or tints. This color failure may be corrected by image processing to some extent. However, since the correction by image processing is limited, it is preferable to control color balance of the image (image data) when the original image is read. This will enable to obtain a reproduction image of high quality reliably.
Therefore, read conditions of a scanner should be controlled with regard to the density and the color balance of the original image whenever each of three colors is read, in order to obtain a reproduced image of high quality reliably. The outp
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
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