JP2513647B2 - Image processing device - Google Patents

Description

The present invention relates to an image processing apparatus that reads an image recorded on a color film and corrects density characteristics of a plurality of obtained color component signals. It is about.

[Prior Art] Among the conventional blur image correction methods, few target color images, and most target black and white images. Therefore, when correcting a blurred image recorded on a color film, first read each image data of the blue photosensitive layer, green photosensitive layer, and red photosensitive layer recorded on the film in the same way as a monochrome image, and then read each image data. Image correction was performed by performing digital processing on, and the corrected image was added again as a blue image, a green image, and a red image to obtain a color corrected image.

[Problems to be Solved by the Invention] However, in such a conventional method, there is a problem that a color different from the original color is reproduced in the high contrast portion of the corrected image, and the color reproduction performance is insufficient. Atsuta

The present invention has been made in view of the above conventional example, and an image in which the density characteristics between color components of a plurality of color component signals obtained by reading an image recorded on a color film can be corrected with a simple configuration. An object is to provide a processing device.

[Means for Solving Problems] In order to achieve the above object, the image processing apparatus of the present invention has the following configuration. That is, in an image processing apparatus that reads an image recorded on a color film and corrects the density characteristics of a plurality of obtained color component signals, among the plurality of color component signals, A correction table for storing correction data for the density characteristic of the second color component signal when the density characteristic of the first color component signal is used as a reference, and for the first color component signal using the correction table. , And a correction unit that corrects the second color component signal.

[Operation] In the above configuration, the correction characteristic of the density characteristic of the second color component signal when the density characteristic of the first color component signal of the color film among the plurality of color component signals is used as a reference is stored in the correction table. The correction table is stored and operated to correct the second color component signal of the color film with respect to the first color component signal of the color film.

Embodiments Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

When the optical densities of the blue, green, and red images recorded on the reversal film are read and converted into digital data, the characteristic curves showing the densities of the respective photosensitive layers with respect to the exposure amount do not match, depending on the film. Therefore, correct subject data may not be obtained even if those data are processed and combined again.

FIG. 2 is a diagram showing the density characteristics of Kodak Kodachrome 64 (daylight type film) with respect to the exposure amount of each photosensitive layer.

Reference numeral 20 is a red (R) photosensitive layer, 21 is a green (G) photosensitive layer, and 22 is a curve showing the density characteristics with respect to the exposure amount of the blue (B) photosensitive layer.

FIG. 3 is a diagram showing a case where a neutral gray subject light amount distribution indicated by 30 is exposed to a film in which the characteristics of the respective R, G, B photosensitive layers are different.

Reference numerals 31 to 33 show the density distributions in the respective photosensitive layers after the subject light amount distribution 30 is recorded on the blue, green and red photosensitive layers and the development processing is performed. Therefore, even if the density distributions of the photosensitive layers for the three colors recorded on this film are correctly read, digitized, and reproduced, the object light quantity distribution
Data corresponding to 30 cannot be obtained.

When the recorded image becomes a blurred and deteriorated image due to camera shake or the like during shooting of the subject, the high-contrast portion of the image has a slightly reduced contrast due to the blur.
However, in the recorded image, at least a difference in the density distribution due to the difference in the characteristic curves of the photosensitive layer occurs as shown in FIG.

Generally, when correcting a blurred image, a process that amplifies the contrast of high spatial frequency components deteriorated due to blurring is performed, so the difference in the density distribution on the film is amplified. Color misregistration will be noticeable in later images.

Therefore, in this embodiment, three images of blue, green, and red are read as digital data from the color film, and then the process of correcting the difference between the characteristic curves of the photosensitive layers is performed.

 The processing will be described below.

 FIG. 1 is a functional block diagram showing this embodiment.

Reference numeral 10 is a photosensitive film having the characteristics shown in FIG. 2, for example, and the image density input section 11 inputs the image density of each of the red, blue and green photosensitive layers of the photosensitive film 10. Reference numeral 12 is an A / D conversion unit for inputting analog density data from the image density input unit 11 and converting it into a digital signal. Reference numeral 13 is a correction unit for correcting the images of the blue and red photosensitive layers using the characteristic curve of the green photosensitive layer of FIG. 2 as a reference characteristic curve.

Reference numeral 14 is a correction table used by the correction unit 13. The creation of the correction data of the correction table 14 will be described below.
In the characteristic curve of FIG. 2, blue for a certain exposure amount E ₀ ,
The optical densities of green and red are D _B (E ₀ ), D _G (E ₀ ), D
_{Let R} (E ₀ ).

Thus, D _G (E ₀₎ for _{D B (E 0) -D B} (E 0) D R D G (E 0) for _{(E 0) -D R (E} 0) to when plotted while changing the E ₀ , The corrected density curve shown in FIG. 4 is obtained. Based on this corrected density curve, a correction table is created in advance for each film type.

In FIG. 4, 40 is a blue correction curve obtained by D _G (E ₀ ) −D _B (E ₀ ), and 41 is a red correction curve obtained by D _G (E ₀ ) −D _R (E ₀ ). It is a correction curve.

The density value of blue image d _B (x, y), of the red image density value d _r (x,
y) (x, y are variables indicating the position in the image), and the data of the correction table 14 of the film is C _B for the blue photosensitive layer,
When C _R is set for the red photosensitive layer, the density value corrected by the correction unit 13 is d _B (x, y) + C _B (d _B (x, y)) d _r (x, y) + C _R (d _r (x, y)) is obtained.

By using the data corrected in this way to correct the image in the correction unit 15, it is possible to prevent the reproduction of an incorrect color. The image correction includes blur image correction, blur image restoration, and restoration of a deteriorated image formed by a low MTF (modulation transfer function) characteristic.

Although the characteristic curve of the green photosensitive layer is used as the reference characteristic curve in this embodiment, the reference characteristic curve can be arbitrarily selected. However, if any one of the characteristic curves of the blue, green and red photosensitive layers is used as the reference characteristic curve, the correction table data becomes 1
There is an effect that it can reduce.

Further, the color film is not limited to the bogi color film (reversal color film), and is similarly effective for the negative color film.

As described above, according to this embodiment, it is possible to realize image correction with good color reproduction performance.

As described above, according to the present invention, it is possible to correct the density characteristic between the color components of a plurality of color component signals obtained by reading an image recorded on a color film with a simple configuration. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a functional block diagram of this embodiment, FIG. 2 is a diagram showing a characteristic curve of a color positive film, FIG. 3 is a schematic diagram showing a difference in recording characteristic in a high contrast portion, and FIG. It is a figure which shows an example of a correction | amendment density curve. In the figure, 10 ... Photosensitive film, 11 ... Image density input section, 12
…… A / D converter, 13 …… corrector, 14 …… correction table, 1
5 …… Correction part, 20 …… Red photosensitive layer characteristic curve, 21 …… Green photosensitive layer characteristic curve, 22 …… Blue photosensitive layer characteristic curve, 40
…… Blue correction curve, 41 …… Red correction curve.

Claims (1)

(57) [Claims] 1. An image processing apparatus for reading an image recorded on a color film, and correcting the density characteristics of a plurality of obtained color component signals, wherein: A correction table that stores correction data of the density characteristic of the second color component signal when the density characteristic of the first color component signal of the film is used as a reference, and the first color component signal using the correction table. On the other hand, an image processing apparatus comprising: a correction unit that corrects the second color component signal.