JP2599476B2 - Exposure control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control apparatus, and an image copying apparatus such as an automatic photographic printing apparatus for printing an image from a color original image to a copying photographic material, particularly from a color film to a color paper. The present invention relates to an exposure control device for controlling the amount of exposure.

[Conventional technology]

In general, the exposure amount when reproducing a color image from a color original image to a copying photographic material is determined by using a photometric device equipped with a color separation filter composed of a dye filter or a vapor deposition filter using red (R), green (G), The integrated transmission (or reflection) density of blue (B) light is measured, and each of R, G, and B light is determined. In order to accurately determine the amount of exposure, it is necessary to measure the amount of light that actually contributes to the exposure of the copying photosensitive material. To this end, the spectral sensitivity distribution of the photometric device must match the spectral sensitivity distribution of the copying photosensitive material. There is. The spectral sensitivity distribution of the copying photographic material is asymmetric with respect to the wavelength at which the sensitivity becomes maximum. However, in dye filters and vapor deposition filters,
It is necessary to combine many filters in order to make the transmittance distribution asymmetrical, so that it is difficult to mass-produce and to manufacture it with high accuracy.

Therefore, the photoresist exposure device decomposes the light from the original image into spectral light, and weights and adds the decomposed light to match the spectral sensitivity distribution of the photometric device with the spectral sensitivity distribution of the photosensitive material. Techniques for causing this to occur are known. JP-A-58-88624 discloses a photoresist exposure apparatus that performs the above-described processing using a diffraction grating, a converging optical system, and a photodetector. However, spectral sensitivity characteristics are reduced due to the mutual arrangement of these optical elements. A complex mechanism is needed to keep it from changing. JP
Japanese Patent Application Laid-Open No. 61-95525 discloses a photoresist exposure apparatus in which a number of interference filters are arranged instead of the diffraction grating. However, since a large number of interference filters are required, it is difficult to mass-produce when the number of photometric wavelengths is large. In addition, since the light is divided into a large number of spectra, one spectral width is narrowed and the amount of light is reduced. However, there is a problem that the sensitivity becomes insufficient. In a color photographic printer, Japanese Patent Application Laid-Open No. 1-134353 discloses that a light from an original image is spectrally decomposed using a prism, a diffraction grating, or a spectral filter, and a part of a copy document is slit into a photoelectric sensor panel. A technique for forming an image is disclosed. In this technique, different photometric positions are represented in rows of a panel, and spectrum light corresponding to the photometric position is converted into an electric signal in an example of a panel. This technique has the same problem as described above because it uses a diffraction grating and a spectral filter.
Also, since the light is split by refraction using a prism, the projection light must be parallelized, the device must be large, and the amount of light must be greatly reduced due to decomposition into rows and columns. There is a drawback that a large light quantity difference occurs in the spectrum and that photometry cannot be performed on the same panel. Japanese Patent Application Laid-Open No. 1-142719 discloses that a prism or a diffraction grating, a lens, and a two-dimensional array sensor are used. However, since a prism or a diffraction grating is used, there is a similar problem as described above.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an exposure control apparatus having a photometric sensor having a spectral sensitivity distribution with high accuracy that can be mass-produced at a small size and at low cost. I do.

[Means for solving the problem]

In order to achieve the above object, an exposure control device of the present invention comprises:
A red light sensitive wavelength band, a green light sensitive wavelength band, each of which includes a maximum value of the spectral sensitivity of the copying photosensitive material for copying the original image,
A first sensor for measuring the original image by splitting a wavelength band corresponding to each of the maximum sensitivity wavelength bands of the blue light sensitive wavelength band into a plurality of separated light beams, and dividing the original image into a plurality of red light, green light, and blue light A second sensor for photometric measurement, and a composite value equal to that obtained by photometrically measuring the photosensitivity of the first photosensitive sensor by adding a weight to the sensor having the same or similar spectral sensitivity distribution as the spectral sensitivity distribution of the copying photosensitive material to be copied. Calculating means for calculating the basic exposure amount based on the combined value obtained by the calculating means, or based on the color control value determined based on the combined value obtained by the calculating means and the photometric value of the second sensor. Control means for determining a basic exposure amount based on the determined density control value and controlling the exposure amount based on the basic exposure amount.

The wavelength band corresponding to the maximum sensitivity wavelength band is 460 to 485 nm
, 540 to 560 nm, and 680 to 710 nm.

The first sensor can be provided with a filter in which interference films for dispersing a wavelength band corresponding to at least one maximum sensitivity wavelength band into a plurality of decomposition lights are deposited at different positions on the same plane.

Further, the first sensor has a first interference film that separates a wavelength band corresponding to the maximum sensitivity wavelength band into a plurality of decomposed lights and a wavelength band other than the wavelength band corresponding to the maximum sensitivity wavelength band from the interference film. A filter may be provided on which a second interference film that separates the light having a wide half-value width into the separated light is deposited. The first sensor has a first interference film that splits a wavelength band corresponding to the maximum sensitivity wavelength band into a plurality of decomposed lights, and a wavelength band other than the wavelength band corresponding to the maximum sensitivity wavelength band is wider than the interference film. A filter may be provided on which a second interference film that splits the light into decomposed light at wavelength intervals is deposited.

[Operation] The first sensor includes a red light sensitive wavelength band, a green light sensitive wavelength band, and a blue light sensitive wavelength band that include each of the maximum values of the spectral sensitivity of the copy photosensitive material for copying the original image. The wavelength band corresponding to the maximum sensitivity wavelength band is divided into a plurality of decomposed lights and measured. The spectral sensitivity distribution of copying photographic materials, especially photographic color paper, has a similar spectral sensitivity distribution shape regardless of the manufacturer, type, etc., and the maximum value of the spectral sensitivity of various color papers is almost the same wavelength band. Exists. Therefore,
A wavelength band corresponding to this maximum sensitivity wavelength band is divided into at least two or more, preferably three or more, separated light beams, and photometry is performed.
In particular, it is possible to easily obtain a combined value equal to that measured by a sensor having the same or similar spectral sensitivity distribution as that of various color papers. As the weight, a value obtained from the spectral sensitivity distribution of the sensor or the like can be used. Even if the spectral sensitivity distribution of the first sensor deviates from the spectral sensitivity distribution of the copying photographic material, it is possible to obtain the above composite value by changing the weight. For this reason, the calculating means weights and adds the photometric value of the first sensor to calculate a combined value equal to that measured by a sensor having the same or similar spectral sensitivity distribution as the spectral sensitivity distribution of the copy photographic material.

As described above, by adding a weight to the photometric value of the first sensor, the spectral sensitivity distribution of the first sensor and the spectral sensitivity distribution of the copy photosensitive material can be matched or approximated. The basic exposure amount is determined based on the composite value obtained by the means, and the exposure amount can be controlled with the basic exposure amount.

The second sensor divides the original image into a large number of R, G, B
Measure the light. The first sensor is capable of determining a color control value based on a combined value obtained by the arithmetic means for performing photometry by splitting the light into a plurality of separated lights. The spectral sensitivity distribution of the second sensor does not necessarily have to exactly match the spectral sensitivity distribution of the copying photosensitive material. For this reason, the basic exposure amount is determined based on the color control value determined based on the composite value obtained from the photometric value of the first sensor and the density control value determined based on the photometric value of the second sensor. It may be.

Also, since the second sensor divides the original image into a large number and measures the light, the second sensor performs a predetermined calculation based on the image feature amount obtained from the photometric value (see Japanese Patent Application Laid-Open Nos. 54-28131 and 55-28131). −3
No. 8410 and the technology of JP-A-61-3133 can be used. ) Select the required photometric value (Japanese Patent Application Laid-Open Nos. 62-189457 and 61-189457)
The techniques of 198144 and JP-A-63-311241 can be used. )
It is preferable to determine a correction value according to the image content of the original image by the method described above, and to correct the basic exposure amount with the correction value.

The maximum spectral sensitivity of various color papers is 460 to 4
Since there are wavelength bands of 85 nm, 540 to 560 nm, and 680 to 710 nm, that is, wavelength bands of three primary colors, the first sensor separates each of these wavelength bands into a plurality of separated light beams. It is good to meter.

In order to disperse the maximum sensitivity wavelength band into a plurality of decomposed lights, a filter in which interference films for dispersing these decomposed lights are deposited at different positions on the same plane may be used. In this case, the filters for splitting light may be made separately for each of the split lights, or a filter in which all necessary interference films are deposited on one substrate may be used. For the wavelength band corresponding to the maximum sensitivity wavelength band, the ratio of the photometric value to the exposure amount is large. For a wavelength band other than the wavelength band corresponding to, the ratio of the photometric value to the exposure amount is small, so that the half-width is narrower so that the half-width is measured at wider wavelength intervals with the broader decomposed light. A filter including a first interference film that splits the light into light and a second interference film that splits the half-width into the decomposition light wider than the above may be used.

Since the filter used for the first sensor measures the light with a high degree of accuracy only in the necessary wavelength band to reduce the number of spectroscopy, this filter employs a masking method of masking portions other than the portion where the interference film is deposited and sequentially depositing the same. It can be easily mass-produced.

〔The invention's effect〕

As described above, according to the present invention, each of the maximum sensitivity wavelength bands of the red light sensitive wavelength band, the green light sensitive wavelength band, and the blue light sensitive wavelength band that includes each of the maximum values of the spectral sensitivity of the copying photosensitive material is included. Since the wavelength band is divided into a plurality of separated lights and the light is measured with high accuracy, the number of separated lights can be reduced as compared with the conventional method, and as a result, a special filter that splits the light into a large number of separated lights And prisms are no longer needed,
The effect of being able to provide a small-sized, low-cost and easy-to-mass exposure control apparatus can be obtained. Also, a weight is added to the photometric value of the first sensor to obtain a photometric value equal to that measured by a sensor having the same or similar spectral sensitivity distribution as the spectral sensitivity of the copying photosensitive material. The effect of reducing the degree of coincidence of spectral sensitivity distribution and versatility and coping with manufacturing variations can be obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to a color photographic printer. As shown in FIG. 1, a lamp house 10 having a mirror box 18 and a halogen lamp is disposed below a negative film 20 loaded in a negative carrier and transported to a printing unit. A light control filter 60 is disposed between the mirror box 18 and the lamp house 10. As is well known, the light control filter 60 is composed of three color filters of a Y (yellow) filter, an M (magenta) filter, and a C (cyan) filter.

Above the negative film 20, a lens 22, a black shutter 24 and a color paper 26 are arranged in this order.
The image is formed on the color paper 26 by the image forming device 22.

The first position is in a direction inclined with respect to the optical axis of the imaging optical system and at a position where the image density of the negative film 20 can be measured.
Sensor 28 and the second sensor 30 are arranged.

The first sensor 28 is connected to an exposure calculation circuit 42 via a composite value calculation circuit 40, and the second sensor 30 is directly connected to the exposure calculation circuit 42. The combined value calculation circuit 40 is connected to a storage circuit 38 which stores a weight coefficient, for example, a value specific to the sensor described later and a value corresponding to the spectral sensitivity of the copy photosensitive material. The exposure control circuit 44 calculates the exposure control amount based on the output of the exposure calculation circuit 42 and controls the dimming filter 60.

The first sensor 28 is configured to decompose each of the maximum sensitivity wavelength bands of the color paper into a plurality of decomposed lights on the light incident side, and the B light shown in FIGS. 2 (1), (2) and (3). Filter 50, a G light filter 52, and an R light filter 54. The B light filter 50 separates the wavelength band of 460 to 480 nm corresponding to the B light maximum sensitivity wavelength band of color paper into three separated lights, and the central wavelength of the spectral transmittance distribution is 46.
The interference film B ₁ that disperses to the decomposed light of 0 ± 5 nm, the interference film B ₂ that disperses to the decomposed light whose spectral transmittance distribution has a center wavelength of 470 ± 5 nm, and the decomposed light whose central wavelength of the spectral transmittance distribution is 480 ± 5 nm interference film B ₃ for dispersing is configured by depositing the glass substrate such that each adjacent to. _On the light transmission side of the interference films B ₁ , B ₂ and B ₃ ,
Each of the photoelectric conversion elements 56 is arranged. Note that the spectral transmittance distribution of the B light filter 50 has the same half width as shown in FIG. 3 (1), even though each interference film has the same half width as shown in FIG. 3 (1). Instead of the value width, the spectral transmittance distributions of the adjacent decomposed lights may overlap in a predetermined wavelength band.

The G light filter 52 is for separating the wavelength band of 540 to 560 nm corresponding to the G light maximum sensitivity wavelength band of color paper into two separated lights, and is deposited on the glass substrate so as to be adjacent to each other. Center wavelength of spectral transmittance distribution is 545 ± 5
and a interference film G ₄ which interference film G _3, and the center wavelength of the spectral transmittance distribution splits the decomposition light nm is dispersed into the decomposition light 555 ± 5 nm. Moreover, the interference film G ₂ is provided adjacent the interference film G ₃ in which the center wavelength of the spectral transmittance distribution is split into decomposition light 535 ± 5 nm, the decomposition light having a center wavelength of the spectral transmittance distribution is 510 ± 5 nm interference film G ₁ spectrally is provided adjacent the interference film G _2.
On the light transmitting side of the interference films G ₁ , G ₂ , G ₄ , photoelectric conversion elements 56 are respectively arranged. Incidentally, as shown in the spectral transmittance distribution of the G light filter 52 shown in FIG. 3 (2), the interference films G ₁ ,
Half width of G ₂ is may be greater than the half-width of the interference film G _3, G _4. Also in this filter, the spectral transmittance distribution of the decomposition light may overlap in a predetermined wavelength band.

The R light filter 54 is mainly for separating the wavelength band of 680 to 710 nm corresponding to the R light maximum sensitivity wavelength band of the color paper into three decomposition lights, and is deposited on the glass substrate so as to be adjacent to each other. The center wavelength of the spectral transmittance distribution is 690 ± 5
The interference film R ₃ that disperses the light into the resolved light of nm, the interference film R ₄ that disperses the central wavelength of the spectral transmittance distribution to 700 ± 5 nm, and the light that disperses the central wavelength of the spectral transmittance distribution to 710 ± 5 nm and a interference film R ₅ to. Moreover, the interference film center wavelength of the interference film R ₁ and spectral transmittance distribution center wavelength of the spectral transmittance distribution is split into decomposition light 630 ± 5 nm is dispersed into the decomposition light 660 ± 5 nm
R ₂ is provided adjacent the interference film R _3. Interference film R ₁ ,
On the light transmitting side of R ₂ , R ₃ , R ₄ , and R ₅ , photoelectric conversion elements 56 are arranged similarly to the B light filter 50 and the G light filter 52. As shown in the spectral transmittance distribution of the R light filter 54 shown in FIG. 3 (3), the half width of the interference films R ₁ and R ₂ is larger than the half width of the interference films R ₃ , R ₄ and R _5. It may be large.

The B light filter 50 masks the portions where the interference films B ₂ and B ₃ are deposited, deposits the interference film B _1, and deposits the interference film B ₁ and the portion where the interference film B ₃ is deposited. was an interference film B ₂ deposited by masking, is produced by depositing an interference film B _1, B ₂ interference film B ₃ by site masked was deposited. The G light filter 52 and the R light filter 54 are manufactured in the same manner as the B light filter 50.

Further, as shown in FIG.
The first sensor 28 is configured by disposing the G light filter 52 and the R light filter 54 on a rotatable disk 58 along the circumferential direction of the disk 58. Filter 5
Each of 0, 52, and 54 is divided into a plurality of filter pieces with one interference film as a unit, and the filter pieces are arranged along the circumferential direction of the disk 58 as shown in FIG. 28 may be configured.

In the above description, the filter is configured such that one interference film corresponds to one decomposition light, but the filter may be configured so that a plurality of interference films correspond to one decomposition light. . 6 (1) to (3) shows an example of a G-light filter configured as this, an example of FIG. 6 (1) is disposed an interference film G ₁ ~G ₄ in stripes, Fig. 6 (2)
An example of the interference film G ₁ ~G ₄ arranged in a mosaic shape, FIG. 6 (3) shows each an example in which the interference film G ₁ ~G ₄ radially. A two-dimensional image sensor such as a CCD having a large number of photoelectric conversion elements is arranged on the light transmitting side of these filters. In such a filter, since a plurality of interference films correspond to one decomposed light, the original screen of the film can be uniformly measured. In this case, it is necessary to perform calibration by setting the sensor output corresponding to the base density of the negative film to a reference value, for example, 0.0 before photometry.

The second sensor 30 is composed of a three-color separation filter and a two-dimensional image sensor, and separates the image of the negative film 20 into a large number and measures R, G, and B light. Here, the R light is 60
Light within the range of 0 to 750 nm, G light of 500 to 600 nm, and B light of 400 to 500 nm can be employed. The above maximum sensitivity wavelength band is included in these ranges.

Next, the principle of calculating the composite value will be described with reference to FIGS. As shown in FIG. 7 (1), by providing the above-described filter, the maximum sensitivity wavelength band is divided into three separated light beams for photometry, and the spectral sensitivity distribution is as shown in FIG. 7 (2). The spectral characteristic curve from the actual measurement value when the original image was measured using the sensor
₁ (λ), the true spectral characteristic curve is represented by f ₂ (λ). In the present invention, the spectral characteristics of the original image mean a spectral transmittance distribution, a spectral reflectance distribution, a spectral density distribution, a spectral reflection density distribution, or characteristics and values corresponding thereto. The seventh
S _{λ 1} , S _{λ 2} , and S _{λ 3 in} FIG. 2 are sensors S ₁ , S ₂ ,
Shows the respective spectral sensitivity distribution of S _3. Since the spectral sensitivity distributions S _{λ 1} , S _{λ 2} , and S _{λ 3} of the three sensors have distributions, the photometric value of the film dye has a value different from the true value. Since the spectral characteristics of the original image (that is, the film dye) have a gentle distribution shape, it can be estimated with a small number of wavelengths. Therefore, λ ₁ is S _{λ 1} and
Medium wavelength of the center wavelength of S _{λ 2, λ 2} is the middle wavelength of the center wavelength of S _{lambda 2} and S _{λ 3, λ 0} is such that the center wavelength of the S _{lambda 1} is lambda ₀ and lambda ₁ of the intermediate , lambda ₃ is lambda ₀ to be the middle of the central wavelength lambda ₂ and lambda ₃ of _{S λ 3 <λ 1 <λ} 2 <
A division point of λ ₃ is determined, and the spectral sensitivity distribution of each sensor is divided into small sections [λ ₀ , λ ₁ ], [λ ₁ , λ ₂ ], [λ ₂ , λ ₃ ], for example, [λ ₀ , λ _1] ], The spectral characteristics a to b of the original
Ｄd. The true values at the center wavelength in each subsection are T ₁ , T ₂ , T ₃ , the examples are F ₁ , F ₂ , F ₃ , and the spectral sensitivity distributions of the sensors are S _{λ 1} , S _{λ 2} , S _{λ 3.} And Further, it is assumed that the spectral sensitivity distribution of the copying sensitive material is represented by 7 (3), the spectral sensitivity of the copying sensitive material at the point of the center wavelength of each sensor and _{P 1, P 2, P 3} . When the actual measurement value F ₂ of the small section [λ ₁ , λ ₂ ] is represented using the true value and the spectral sensitivity distribution of each area of the sensor, the following equation is obtained.

Note that the measured values F ₁ and F ₃ can be obtained in the same manner as described above.

 The above equation (1) is generally expressed as follows.

Here, j is a number assigned according to the wavelength and j =
1, 2, 3,... N, where i is a number assigned to the peak value of the spectral sensitivity distribution of the sensor, that is, a number assigned to each region of the sensor, and in the above case, i = 1,
Two, three.

When the number of sensor regions is n and the light is divided into n pieces of decomposed light for photometry, the following equation is obtained.

The spectral sensitivity distribution of the sensor Sadamari spectral sensitivity S _{lambda i} in the arbitrary section [j-1, j] if is previously determined, the equation (3) Is a predetermined value (eigenvalue) unique to the sensor. When the relationship between the true value, the measured value, and the eigenvalue is represented by a matrix with this eigenvalue as Sij, the following is obtained.

F = T · S (4) where It is.

Therefore, when the inverse matrix of S is represented by S ⁻¹ , the true value T is S ^−1.
Represented by F.

The photometric value when measured with a sensor having the same spectral sensitivity distribution as the photosensitivity distribution of the copy photosensitive material, that is, the composite value Tp,
It is expressed as follows.

Here, K = ΣΔPi / n, ΔPi is an arbitrary section [j−1,
j] is the wavelength width λj−λj− ₁ . Therefore, the second
In the case of the sensor including the filters shown in FIGS. 1A to 1C, the spectral sensitivity distributions S _{λ 1} and S _{λ of} each photoelectric conversion element
_The values S ₁₁ , S ₂₁ , S ₃₁ ... unique to the sensor obtained by integrating _{λ 2} ... with respect to the wavelength λ with the integration section being the same as the small section, and the spectral sensitivities P ₁ , P ₂ , P _{3 of the} copying photosensitive material .. Or a value corresponding thereto is stored in the storage circuit 38, and a film pigment, that is, a spectral distribution of an image frame to be printed is predicted as a value unique to the sensor, and then the calculation of the above equation (6) is performed. The composite value Tp can be obtained. The spectral sensitivity distribution of each sensor may be stored in place of the value specific to the sensor, and the spectral sensitivity distribution itself may be stored in place of the spectral sensitivity of the copying photosensitive material. Also, the values S ₁₁ , S ₂₁ ,... Specific to the sensor and the spectral sensitivity of the copying photosensitive material.
A weight coefficient multiplied by P ₁ , P ₂ ... Or a value corresponding thereto may be stored.

FIG. 8 shows a composite value operation circuit 40 and an exposure amount operation circuit 42.
In step 100, a photometric value Fi corresponding to each of the photoelectric conversion elements measured by the first sensor 28 is taken in step 100, and a unique value Sij stored in the storage circuit 38 is taken in step 102. Read. In the next step 104, as described above, the photometric value Fi and the eigenvalue S
The true value Ti is predicted using ij. Next Step 106
Then, the spectral sensitivity distribution Pi of the copy photosensitive material is read from the storage circuit 38, and in step 108, the composite value Tp is calculated based on the above equation (6). Then, in step 110, the composite value Tp
Is Tr, Tg, Tb, and the screen average photometric value of the second sensor is mr, m
As g and mb, the basic exposure amount Dp is calculated according to the following equation. Here, r, g, and b represent red, green, and blue, respectively, and p
Is any one of r, g, and b.

Dp = (mr + mg + mb) / 3 + Tp- (Tr + Tg + Tb) / 3 (7) Equation (7) performs color control by the first sensor and density control by the second sensor. 3 of the second sensor
The color difference of the first sensor is added to the color average density. The correction value of the basic exposure amount by the second sensor is
The correction value of the density for the three-color average density of the second sensor and the color correction value of mr, mg, and mb of the second sensor may be obtained and added to the basic exposure amount Dp. Needless to say, in order to increase the calculation accuracy, the spectral sensitivity distribution of the second sensor should be closer to the copying photographic material.

The basic exposure amount Dp may be calculated according to the following equations (8), (9), (10), and the like.

Dp = (mr + mg + mb) / 3 + (Tp−Tg) (8) Dp = mg + (Tp−Tg) (9) Dp = Tp (10) The exposure amount control circuit 44 follows the basic exposure amount Dp. The exposure amount is controlled by controlling the dimming filter.

In order to correct the density, color area, etc. based on the shooting scene, a correction amount is calculated based on the photometric value of the second sensor, and a value obtained by adding the correction value to the basic exposure amount is used as an exposure control value. To control the exposure amount. The method of calculating the correction amount and the method of controlling the exposure amount are described in JP-A-63-312441 and JP-A-63-31124.
It is described in detail in, for example, -311242.

As described above, according to this embodiment,
As described in No. 1241, etc., it is possible to print film types having different film properties under the same printing conditions, and it is possible to obtain an effect that prints of higher quality than before can be made from various types of films. If applied to a color copier, original images with different spectral sensitivity distributions (photo originals, print originals,
Illustrations, perspective solid objects, etc.) can be copied under the same copy conditions.

In the above embodiment, the basic exposure amount Dp is shown as in equations (7) to (10). However, the image feature amount (for example, the maximum density, the minimum density, the partial area density) obtained from the photometric value of the second sensor is used. ) May be used as the basic exposure amount. A correction formula (or conversion table) for the photometric value of the second sensor is created from the correspondence between the photometric values of the first and second sensors, and the photometric value of the second sensor is converted to the photometric value of the first sensor. The exposure value may be converted to an approximated value, the exposure amount may be obtained based on the converted value, and exposure control may be performed. Further, the exposure amount obtained by the second sensor may be corrected by the photometric value obtained by the first sensor. In this case, the difference between the basic exposure amounts obtained from the first and second photometric values may be used as the correction value.

Further, the example in which the eigenvalue is stored in the storage circuit has been described, but the eigenvalue may be obtained by calculation after storing the spectral sensitivity distribution of each region of the sensor.

Also, in the above description, an example is described in which the spectral sensitivity distribution of the original image is estimated from the photometric value and the weight obtained from the spectral sensitivity distribution of the sensor. However, the weight to be added to the photometric value is estimated without estimating the spectral distribution. Is also good. That is, as shown in FIGS. 9 (1) and (2), the spectral sensitivity distributions of the sensors S ₁ , S ₂ , and S ₃ are added to S _{λ 1} , S _{λ 2} , S _{λ 3} and the spectral sensitivity distributions. Are W ₁ , W ₂ , and W _3, and the spectral sensitivity of the copying photosensitive material
Let M ₁ , M ₂ , M ₃ . Spectral sensitivity distribution of copy photosensitive material is a sensor
_They can be matched by weighted addition of the spectral sensitivity distributions of S ₁ , S ₂ , and S ₃ . Since these can be expressed as M = WS when expressed by a matrix, the weights are expressed as follows.

W = S ^-1 · M (11) Accordingly, the spectral sensitivity distribution of each area of the sensor and the spectral sensitivity distribution of the copy photosensitive material are stored in the storage circuit, and the above-mentioned (11)
By calculating the expression, a weight W for estimating a photometric value equal to that measured by a sensor having the same or similar spectral sensitivity distribution as the spectral sensitivity distribution of the copying photosensitive material can be obtained from the photometric value of the sensor. Then, if the photometric value of the first sensor 28 is multiplied by the weight and integrated with respect to the wavelength, the composite value Tp can be obtained.

Further, in the above description, the printing apparatus in which the photometric unit and the light receiving unit are located at the same site has been described. However, a printing apparatus in which the photometric unit and the exposure unit are separated may be used. The second sensor may be a line sensor. Further, the printer to which the present invention is applied is not limited to the printer shown in FIG. 1, and can be easily applied to a printer of the type that performs scanning by driving a film, and the present invention includes the present invention.

The first sensor may be separated into three colors by a die mirror or a prism other than the examples in FIGS. 4 and 5, and may be attached to the filter described in the present invention. Further, the filter of the present invention can be applied to a filter in which a silver Ag film having a different thickness is sandwiched between MgF ₂ films and a spectral wavelength is selected by the thickness of the Ag film.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a color photographic printer to which the present invention can be applied, FIGS. 2 (1) to (3) are plan views showing a filter used in the sensor of this embodiment, and FIG. FIGS. (1) to (3) are diagrams showing the spectral transmittance distributions of the sensors shown in FIGS. 2 (1) to (3), FIG. 4 is a plan view showing a state where a filter is mounted, and FIG. FIGS. 6 (1) to (3) are plan views showing other examples of attachment of the filter, and FIGS. 6 (1) to (3) are plan views showing another example of the filter used in the sensor of this embodiment. FIGS. ) Is a diagram for explaining the operation principle of the composite value, FIG. 8 is a flowchart showing the operation routine of the above embodiment,
FIG. 9 is a diagram for explaining another example of calculating a composite value. 28 ... first sensor, 30 ... second sensor.

Claims (5)

(57) [Claims] 1. A red light sensitive wavelength band, a green light sensitive wavelength band, and a blue light sensitive wavelength band each containing a maximum value of spectral sensitivity of a copying photosensitive material for copying an original image. A first sensor that splits the corresponding wavelength band into a plurality of decomposed lights to measure the original image, a second sensor that splits the original image into a plurality of pieces to measure red light, green light, and blue light; Calculating means for calculating a composite value equivalent to that obtained by photometry with a sensor having the same or similar spectral sensitivity distribution as the spectral sensitivity distribution of the copying photographic material to be copied by adding weight to the photometric value of the sensor; The basic exposure amount is determined based on the combined value, or the basic exposure amount is determined based on the color control value determined based on the combined value obtained by the arithmetic unit and the density control value determined based on the photometric value of the second sensor. Determine the exposure and control the exposure based on the base exposure Exposure control device comprising a control means. 2. A wavelength band corresponding to the maximum sensitivity wavelength band,
460-485nm wavelength band, 540-560nm wavelength band, 680-710nm
The exposure control device according to claim 1, wherein the exposure control device includes: 3. The filter according to claim 1, wherein the first sensor includes a filter in which interference films for dispersing a wavelength band corresponding to at least one maximum sensitivity wavelength band into a plurality of decomposition lights are deposited at different positions on the same plane. The exposure control device according to claim 1 or 2, wherein 4. The first sensor according to claim 1, wherein the first interference film splits a wavelength band corresponding to the maximum sensitivity wavelength band into a plurality of decomposed lights and a wavelength band other than the wavelength band corresponding to the maximum sensitivity wavelength band. The exposure control device according to claim 1 or 2, further comprising a filter on which a second interference film that separates the separated light having a half width wider than the interference film is deposited. 5. The first sensor according to claim 1, wherein said first sensor is a first interference film that separates a wavelength band corresponding to a maximum sensitivity wavelength band into a plurality of decomposition lights, and a wavelength band other than a wavelength band corresponding to the maximum sensitivity wavelength band. The exposure control device according to claim 1 or 2, further comprising a filter on which a second interference film that separates the decomposed light into wavelengths wider than the interference film is provided.