JPS6014570A - Input signal processing method of negative original - Google Patents

Abstract

PURPOSE:To discriminate easily a hue signal from a density signal by converting a negative original density signal read by photoelectric-scanning on a negative original into a density signal corresponding to a positive image so that the ratio of the weight of the three primary colors of the density signal corresponding to the positive image is made constant at all times and identical. CONSTITUTION:After the input signal obtained by photoelectric-scanning the negative original loaded to an input drum 1 is converted into the density signal by a logarithm converting circuit 2, the result is inputted to an input signal processing section 4 via an AD converter 3, where the signal is converted into a positive original density signal being the equivalent neutral density in which the ratio of the weight of the B, G, R signals is constant and identical, and then the result is inputted to a color processing section 5 to be called the heart of the system, where the signal is processed by color processing, gradation processing and sharpness processing. Thus, the density signal outputted from a color processing section 5 is inputted to a modulator 8 via an output signal processing section 6 and further a DA converter 7 so as to modulate laser light outputted from a light source 9, thereby reproducing a desired picture on an output drum 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides density signals or luminance equivalent to a negative image obtained by photoelectrically scanning a negative original with a high-precision scanner such as a color scanner or laser color printer, or with a color image pickup tube, color image pickup plate, etc. The present invention relates to a method of converting a signal into a density signal or a luminance signal equivalent to a Bonn image.

Various methods have been developed in various fields as signal processing methods for color images, and one of them is signal processing performed in a telecine that converts a movie film into a television film.

For example, if a reproduced image is obtained by photoelectrically scanning an image original with a high-precision scanner such as a layout scanner or a laser color printer, a signal processing section is installed in the middle of the process to perform color correction (%) on the input density signal. Gansho 57-62125
), sharpness enhancement (Japanese Patent Application No. 57-57743) or gradation setting (Japanese Patent Application No. 57-72781). However, there are two types of image originals: a positive original and a negative original, and there are two types of desired reproduced images: a positive image and a negative image. If a signal processing section is provided separately for each, there will be an inconvenience that the scale of the /stem becomes large. In such a case, it would be very convenient if, for example, j signal processing sections could perform all signal processing related to all combinations. However, in order to achieve this, it is necessary to enable the EJ function to process density signals obtained from either a positive original f-height or a negative original f-height original in the same processing section.

However, when performing signal processing in the signal processing section, it is not preferable to handle the density signal from the negative original as is. This is because the r value of the j-th negative photosensitive material is low, so the exposure range is wide, and each of the three primary colors (B) is exposed under different exposure conditions.

This is because the weight ratio of the density signals of the input density signals is different, which makes it difficult to judge all the hues from the input density signals, which causes inconveniences in color processing.
This is because this density signal is a signal equivalent to a negative image and is therefore difficult to understand intuitively. In other words, if the input original is a positive original, the density signal sound from this blank original can be input to the signal processing section as is, but if the input original is a negative original, the density signal from this negative original can be input to the signal processing section as is. It is desirable to convert the density signal into a density signal equivalent to that of the original and then input it to the signal processing section.

The present invention has been made for such an application, for example, and uses weights of the three primary colors of the positive density signal: a negative density signal (gold) read by photoelectrically scanning a negative original, and a corresponding positive density signal. The overall purpose of this invention is to provide a signal processing method for converting in real time so that the ratio of The weight ratio of the three primary colors of the negative original density signal sound read by photoelectrically scanning the negative original with a high-precision scanner, the corresponding positive image phase density signal, and the density signal corresponding to this Bonn image is always kept constant. All features are that the conversion is done equally. Since negative originals usually use a low r (gamma) sensitive material, they are photographed under various exposure conditions (aperture ranges from 12 degrees to +/18 degrees), and therefore, for each of these various exposure conditions, 3
Negative W of density signals of primary colors (B, G, J()), overall density signal of original input density signal, virtual negative original density signal (density signal corresponding to the original when the subject is properly exposed and photographed with negative photosensitive material) ) and then converting it into a virtual positive original density signal (density signal corresponding to the original when the entire subject is properly exposed and photographed with positive sensitive material).The above individual conversions include: Although it is preferable to use digital circuits such as converters, converters, multipliers, and accumulators, it goes without saying that analog circuits may also be used.

According to the present invention, for example, when a negative original is photoelectrically scanned and color processing is performed on the input density signal, the density signal after conversion is positive, so it is easy to handle intuitively, and furthermore, the three primary colors Equivalent neutral concentration (END) where the weight ratio of the three signals (B・0, It) is constant and equal
This has the advantage that the hue signal can be easily determined from this density signal.

Further, even when monitoring the input concentration signal requires money, the method of the present invention can easily be used, and its practical value is extremely large.

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a block diagram showing an example of the flow of density signals when the present invention is used in a color scanner.

The input signal obtained by fully photoelectrically scanning the negative original loaded on the input drum is converted into an imaginary signal by the logarithmic conversion circuit 2, and then input to the input signal processing section 4 via the AD converter 3. TeB.

The weight ratio of the G, 1%3 signal is constant and the signal is converted into a positive original density signal of equivalent neutral density, which is then input to the hexagonal color processing unit 5, which is the heart of this system, and undergoes color processing. After that, the density signal output from the color processing section 5 is subjected to gradation processing, sharpness processing, etc. 3 After that, the density signal output from the color processing section 5 is processed by the output signal processing section 6 (processing to convert the output density signal into a control signal for the laser light amount, Positive/negative conversion processing (Y
Furthermore, the laser beam inputted to the modulator 8 via the DA converter 7 and outputted from the light source 9 is modulated in two lines to reproduce the entire desired image on the output drum 10. , is a block diagram illustrating a portion of FIG. 1 in more detail.

The input signal is converted into a density signal by a logarithmic conversion circuit 2, and then converted into a digital density signal by an AD converter 3. After that, a masking processing circuit 11 removes all the color cloudiness of the pigment in the input document. The integrated concentration signal is converted into an analytical concentration signal. After that, the processing according to the present invention is performed 3. In other words, the density signal output from the masking processing circuit II passes through the exposure correction table 13 (conversion section A) to become a density signal corresponding to a normal exposure and negative original. converted. After this, the density signal is divided into two, one is stored in the Lee-Gaposi conversion table 14, and the other is
Correction calculation circuit 15 (conversion table 14 and calculation circuit 1
5, it is sent to the conversion unit Bi (shading forming). The two signals output from the conversion table 14 and the correction calculation circuit 15 are added by an adder 16 and then input to the color processing circuit 5.

The settings of the converter A and converter B described above will be explained below.

Input negative originals are processed under various exposure conditions (e.g. aperture -2 to +4).
(any value within the range of Can not. That is, this table 13 should be set for each document. Therefore, before the photoelectric scanning for this process,
After roughly pre-scanning the entire document and masking the density signal, it is transferred to the exposure correction signal generator 12, which determines all the conditions under which the document was photographed.5 Based on this determination, the subject Create a complete table to convert the image into a density signal when photographing with a negative photosensitive material and proper exposure, and perform the conversion.

- Set to pull 13. In addition, in this embodiment, Minico/ is used as the table generator J2, and the formula (1
)) All tables are created according to the following. In other words, the /yad density of the original calculated from the density cumulative histogram of the pre-scanned density is 1D81, and the 7yad density of the normally properly exposed original is kDso, and then the characteristic curve of the input original photosensitive material as shown in FIG. Exposure amount - horizontal axis, density - vertical axis) Total D = r (x) "' (a) (However, X-X-1
o
°゛.

(b) (However, ΔX-f'(DS.)-"(D8))
The table value (D") can be obtained using the formula (!) given by (!). In other words, the overall density is reduced by the exposure amount (ΔX) corresponding to the density difference between D8o and DS on the characteristic curve in Figure 3. Process to move in parallel.

In this example, a single point on the input document is used as a material for determining the exposure conditions. However, instead of this single point on the input document, the density of the characteristic point of the original (skin color, sky color, etc.) ) may of course be used. In this embodiment, the entire minicomputer is used for the table generator, but if processing capacity is available, the entire digital processing circuit consisting of a microprocessor and its interface may be used.

Next, to set the Gabon conversion table 14, first shoot with gray MacBesture 1, all negative sensitive material and positive sensitive material, each with appropriate exposure, and then set the density on the negative sensitive material and the density on the Bonn sensitive material. Gather around 90 data bears, for example. A conversion curve that converts this data into the density obtained when a gray subject was photographed using a negative photosensitive material with proper exposure, and then converted to the density obtained when the same subject was photographed using a positive photosensitive material with proper exposure. The three primary colors ()′.

Create each for M and C). This conversion curve (D"1-fl(pl), = Y, M
,C)2 shown in FIG. This conversion curve is set in the negative/positive conversion table 14. The correction calculation circuit 5 corrects the portions that cannot be corrected in the table.This circuit 15 performs the following calculations.

First, a color Macbeth chart is photographed with proper exposure on all Y-Ga sensitive materials and positive sensitive materials, and the bare data of the density on the negative sensitive material and the density on the positive sensitive material for each color is collected, for example, 10 times.
3 When these data are plotted on Figure 4, there is a slight deviation from the conversion curve in Figure 4 because the data is not for gray.In order to correct this deviation, the data of about 100 pieces are The correction calculation circuit 15 calculates a desired correction value (ΔI) i) using the following equation (C) having coefficients derived from the bare data using the least squares method.
i generate.

ΔDi = D' 1-f(DI) = ao1+a1iDY+a2□DM+a31DC+a4
．． DY1] M+ a5. DMDC+ a6. DcDy
10a7. Dy2+ a8□DM2+ a3. Dc
2'・(c) (i = Y, M, C, r aol, asl,,,
a9. (-coefficient) In this embodiment, in the first half of the conversion, a memory table is provided to convert the input density signal into a density signal corresponding to a negative image and normal exposure. Since negative/positive conversion is performed after converting to a density signal equivalent to normal exposure, even negative originals whose exposure conditions deviate to some extent from normal conditions can be converted to density signals equivalent to normally exposed positive originals with extremely high accuracy. be able to. Furthermore, the conversion in this embodiment only requires the use of a memory table and a multiplier, and does not require a large-capacity image memory or a circuit for performing all integral calculations, allowing calculations to be performed at high speed and in real time. Can be done.

In the above-mentioned embodiment, the correction calculation circuit 15i is provided which performs all minute density corrections, but if the need for strict color correction is not recognized, or if the negative original is black and white, the above two tables 13 may be used. .14'i may be cascaded and combined into one table.

A complete block diagram in this case is shown in FIG. In this block diagram, the table summarized above is used as an exposure correction and negative/positive conversion table 17.
Shown as

In fact, the calculation performed in the correction calculation circuit J5 may be modified, for example, as follows, depending on the required precision.

If high precision is not required, D'i= ao1+a11Dy 1 a2i DM -1
-a3□DC (i = Y + M + C).

When high precision is required, ])'1=ao1+a, HDY+a2.1)M+a3
iDc+a4□DyDM10a5□DMDC+a6□Dc
l) y −1−a,, Dy2+a87DM2+ f!
, 7 Dc2+a j)YDMDC+a, Bl)yDM
2+o1 10a1211)Y2DM・ Correct.

Note that although the above-described embodiments are based on the premise that processing is performed by digital circuits, it goes without saying that processing may be performed by analog circuits.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the density signal flow when the present invention is used in a color scanner, Fig. 2 is a block diagram showing a part of Fig. 1 in more detail, and Fig. 3 shows the appearance of a manual manuscript. Figure 4 is a graph showing an example of a conversion curve used in the embodiment shown in Figure 2. Figure 5 is a plotter diagram showing one modification of Figure 2. be. 1...-Human drum 2...Logarithmic conversion circuit 3
..... AD converter 4... Input signal processing section 5... Color processing section 6 Output signal processing section 7
...DA converter 8, modulator 9...
... Laser light source 10 ... Output drum 11 ... Masking processing circuit 12 ... Exposure correction table generator 13 ... Exposure correction table 14 ... I-Gaposi conversion table 15 ...・・・
・Correction calculation circuit 16...-Adder 17...
... Exposure correction and negative/positive conversion table No. 1 Fig. 4 5 6 Fig. 2 Input Kai No. b Original Kai No. 3 Fig. 4 t-E'R1,411j
October 14, 1958 Special Issue No. 1fflIli15B-121325 No. 2 Name of the invention Input signal processing method for negative manuscripts 3 Related to the case of the person making the correction Patent applicant Location Nakanuma 21ON, Minamiashigara City, Kanagawa Prefecture Place name Tomi
Shishasha Noilm Co., Ltd. 4, Agent 5-2-1-6 Rokigi, Minato-ku, Tokyo Number of inventions increased by amendment None 2) Page 8, line 13 of the same

Claims (3)

[Claims] (1) Negative original clasp The negative original density signal read by photoelectric scanning is added to the corresponding positive image equivalent density signal, so that the weight ratio of the three primary colors of this positive image equivalent density signal is always a constant value. Input signal processing method 3 for negative original, characterized by converting (2) Converting the conversion into a negative density signal when photographing with all appropriate exposures, and then converting the converted negative density signal into a positive density signal when photographing with all appropriate exposures. 2. The input signal processing method for a negative original according to claim 1, wherein the weight ratio of the three primary colors of the positive density signal is always kept at a constant value. (3) Converting the converted negative density signal into a negative density signal when photographing with proper exposure, and then converting the converted negative density signal into a positive density signal when photographing with proper exposure. 2. The input signal processing method for a negative original according to claim 1, wherein the ratio of the weights of the three primary colors of the positive density signal is set to an equal constant value.