Image analysis – Histogram processing
Reexamination Certificate
1999-01-27
2001-03-06
Tran, Phuoc (Department: 2721)
Image analysis
Histogram processing
C382S260000, C382S274000
Reexamination Certificate
active
06198844
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an image processing method and image processing apparatus capable of dodging or shutting light method, and in particular, to an image processing method and image processing apparatus capable of electronically making the image processing for dodging for the image data read by an image reading means.
In the case where a film (negative-film or positive-film) photographed in a condition with a large brightness difference is developed and printed on a photographic paper, it sometimes occurs that light portions present a uniformly white appearance losing a light tone (whitened or whitening) or dark portions present a uniformly black appearance losing a detailed tone (blackened or black fill-in).
In order to solve the above-mentioned problems of whitening and black fill-in, a technique called ‘dodging’ or ‘burning-in’ is sometimes used. The above-mentioned dodging and burning-in (hereinafter referred to as ‘dodging’ inclusively in this specification) are the methods for obtaining a print without saturation in the light and dark portions, keeping a good contrast and gradation of each photographic object, by giving long time exposure selectively for the area considered to become uniformly white by using a shielding plate with a hole and giving short time exposure selectively for the area considered to become black fill-in by using a shielding plate, while giving usual exposure for the area of intermediate density. Further, in case of printing from a positive-film, a print without saturation can be obtained by the reversed operation of the above.
Furthermore, in the case where an electronic image processing is used, there are like problems of uniform whitening and black fill-in in the final print too; hence, a method for eliminating the uniform whitening and black fill-in by compressing the dynamic range of the original image (described in Japanese laid open patent H9-182093), a method for eliminating the whitening and fill-in by carrying out the dodging image processing preparing a dodging mask from the original (described in Japanese laid open patent H9-18704), and so forth have been proposed.
In the method described in the Japanese laid open patent H9-182093 to compress the dynamic range, it is produced the problem that the contrast and gradation of each photographic object can not be reproduced because the dynamic range is wholly compressed.
Further, in the method described in the Japanese laid open patent H9-18704 to carry out dodging by preparing a dodging mask, the proper effect of dodging is also not to be obtained like the method described in the Japanese laid open patent H9-182093, because the original is subjected to low-pass filter processing and then a dodging mask having a gradation compressed by a gradation-compressing LUT is applied together with the original image.
Furthermore, in some cases of electronic image processing, soft focusing is practiced. In these cases, in order to obtain a soft focus image with an appearance of blurred light as obtained by using a soft filter at the time of photographing, it is required to superpose a mask image with respect to respective numerical values corresponding to the brightness (energy quantity E) at the time of photographing.
On the other hand, in a general print system, it is favorable that the image data is handled in a unit system wherein the higher brightness domain is compressed such as density and L*, in order to secure a sufficient range of gradation reproduction and the precision of image processing.
For this reason, in order to obtain a favorable soft focus image, an additional processing such as converting density or L* into E→composing processing→converting E into density or L*; hence, the load for the computer is increased owing to the necessity to keep the precision of processing high and the increase of the amount of calculation process.
Further, as another means for obtaining soft focus effect, a soft focus processing to be made at the time of printing can also be available; it is characterized by obtaining a print of a spread color, and in low key. In this case too, it can not be actualized by merely blending the image data values corresponding to density or L*, but it requires the calculation process such as converting density or L* into print exposure quantity E′→composing processing→converting E′ into density or L*, resulting in a heavy load like the soft focus processing of the type made at the time of photographing.
Furthermore, in order to obtain the soft focus effect, it is necessary to carry out a blurring filter processing of enough size; hence, it gives a large burden to the image processing system, making a high-speed processing difficult.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to actualize an image processing method and an image processing apparatus capable of practicing an image processing for dodging getting rid of the saturation at the light portions and at the dark potions with the contrast and gradation reproduction of each photographic object kept good.
Further, it is another object of this invention to actualize an image processing method and an image processing apparatus capable of practicing a soft focus process suitable for the respective purposes without deteriorating the color tone and without increasing the amount to be processed.
The above-mentioned objects can be accomplished by the image processing method and image processing apparatus shown in the following:
An image processing method comprises the steps of:
obtaining the data concerning the brightness of an original image,
dividing said data concerning the brightness into a plurality of groups for the respective brightness domains on
the basis of the histogram of said data concerning the brightness,
preparing correction information for correcting said data concerning the brightness for each of said plurality of groups, and
executing image processing to said original image on the basis of said correction information.
An image processing apparatus comprises:
data obtaining means for obtaining the data concerning the brightness of an original image,
dividing means for dividing said data concerning the brightness into a plurality of groups for the respective brightness domains on the basis of the histogram of said data concerning the brightness,
correction information preparing means for preparing correction information for correcting said data concerning the brightness for each of said plurality of groups, and
image processing means for executing image processing to said original image on the basis of said correction information.
Further, the above-mentioned problems can be solved by any one of the methods and apparatus as favorable embodiments of the invention shown in the following:
(1) An image processing method comprising the steps of:
obtaining the data concerning the brightness out of the original image data,
dividing said data concerning the brightness into a plurality of groups according to the set of said data concerning the brightness,
preparing a mask on the basis of at least one of said plurality of groups, and
executing image processing to image data on the basis of said mask.
An image processing apparatus for carrying out dodging image processing comprising:
means for obtaining the data concerning the brightness out of the original image data,
means for dividing said data concerning the brightness into a plurality of blocks according to the set of the frequencies of emergence of said data concerning the brightness,
means for preparing a dodging mask on the basis of at least one of said plurality of blocks, and
image processing means for carrying out addition calculation with this dodging mask and the corresponding pixels of the original image.
Incidentally, in this specification, ‘data concerning the brightness’ means, in addition to the brightness, various pieces of information concerning the lightness of the photographic object such as the transmission (reflection) density of the original, the print expo
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Konica Corporation
Tran Phuoc
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