JPH02150830A - Light measuring instrument for photographic printer - Google Patents

Abstract

PURPOSE:To measure light with high accuracy by adjusting the color balance of a light source when three color light beams are separated and measured at respective points of an image. CONSTITUTION:For the tricolor separate light measurement, color filters corresponding to the colors to be measured are put in a printing optical path and respective points of the image of a photographic film which are projected through the color filters are measured by an image sensor 2 through an ND filter 6. The image sensor 2 is so constituted that photoelectric conversion parts 4 which are arrayed in a matrix correspond to the three colors, so signal charges of the photoelectric conversion parts 4 corresponding to the colors of the color filters are led out selectively. Then an ND filter which is different in density corresponding to the spectral brightness characteristics of the light source is arranged in each area to set the spectral sensitivity of the image sensor 2 according to the light source. Consequently, accurate light measurement is enabled and a print photograph with a proper exposure quantity is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photometry device used in an additive photographic printer for performing three-color separation photometry on each point of an image.

[Conventional technology]

In an additive color photographic printer, a red filter, a green filter, and a blue filter are arranged between the light source and the photographic film, and when printing a photograph, the color filters are selectively inserted into the optical path and red exposure is performed.

Green exposure and blue exposure are performed sequentially. Additionally, additive color photographic printers are also known that are equipped with an image sensor to perform high-precision exposure control, and sequentially insert color filters into the optical path during photometry to perform red, green, and blue photometry. ing. This photo printer uses three-color separation photometry to determine the three-color density of each point in the image, and extracts various characteristic values for each color from the three-color density obtained.
The exposure amounts for red, green, and blue are calculated using these characteristic values.

[Problems to be Solved by the Invention] Generally, the photometric values of the three colors vary depending on the spectral luminance characteristics of the light source, but in conventional additive color photographic printers, the image sensor Because the method uses three-color separation photometry, it was not possible to perform highly accurate photometry.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photometric device for a photographic printer that can perform highly accurate photometry by adjusting the color balance of a light source.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a photoelectric conversion section for red from which a signal charge obtained by photoelectrically converting incident light is extracted during red photometry using a red filter, and a photoelectric conversion section for photoelectrically converting incident light during green photometry using a green filter. An image sensor is provided in which a green photoelectric conversion section from which converted signal charges are extracted and a blue photoelectric conversion section from which signal charges obtained by photoelectrically converting incident light are extracted during blue photometry using a blue filter are arranged in a matrix, In each photoelectric conversion part of this image sensor,
ND filters having density values determined for each color according to the spectral luminance characteristics of the light source are arranged. Instead of the ND filter, a mask having an aperture ratio determined for each color depending on the spectral luminance characteristics of the light source can also be used.

[Operation] When performing three-color separation photometry, a color filter corresponding to the color to be photometered is inserted into the printing optical path, and the ND is determined for each point of the photographic film image illuminated through this color filter.
The light is measured by an image sensor through a filter. In this image sensor, since the photoelectric conversion sections arranged in matrix correspond to three colors, signal charges of the photoelectric conversion sections corresponding to the colors of the color filters are selectively taken out. At this time, since an ND filter or mask is arranged according to the color light to be measured by the photoelectric conversion section, photometry is performed taking into account the color balance of the light source.

〔Example〕

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

FIG. 1 shows an image sensor 2 and an ND filter 6. As shown in FIG. The image sensor 2 has a large number of photoelectric conversion units 4 arranged in a matrix on its photosensitive surface 3. On this photosensitive surface 3, an ND filter 6 is arranged to adjust the color balance of a light source 110 used in a photographic printer, which will be described later.

In the image sensor 2, as shown in FIG. 2, one pixel 2a is composed of nine (3x3) photoelectric conversion units 4, and these nine photoelectric conversion units 4 are converted according to the color during photometry. By selectively reading out the red color 4a, the green color 4b,
It is divided into 4c for blue color, thereby performing pseudo three-color separation photometry. That is, the red photoelectric conversion section 4a photoelectrically converts incident light and reads out accumulated signal charges during red photometry with the exposure red filter 122 shown in FIG. 5 inserted into the printing optical path. During green photometry with the green filter 123 inserted into the printing optical path, the green photoelectric conversion unit 4b photoelectrically converts the incident light and reads out the accumulated signal charge, and the blue photoelectric conversion unit 4c prints the blue filter 124. During blue photometry inserted into the optical path, the incident light is photoelectrically converted and the accumulated signal charge is read out. Photoelectric conversion section 4 of each of these colors
A to 4C are not provided with color filters unlike conventional color image sensors, but for easy understanding, rR is placed in the red photoelectric conversion section 4a, and rR is placed in the green photoelectric conversion section 4b. rGu for the blue photoelectric conversion section 4C,
13J is attached. Further, one photoelectric conversion unit 4 is surrounded by a dotted line, and one pixel 2a is surrounded by a solid line.

The ND filter 6 is made by depositing an ND filter material on a transparent glass substrate or plastic, and the thickness of the ND filter material is adjusted so that the density varies depending on the color light measured by the photoelectric conversion unit 4. has been done. As shown in FIG. 2, in the photoelectric conversion section of this embodiment, in order to reduce the deviation of the color register resin, the photoelectric conversion sections of the same color are arranged in an L shape, and correspondingly, the photoelectric conversion sections of the same color are arranged in an L shape. The area formed is also L-shaped. In addition, in FIG. 3 as well, R, G, and B are attached to each area for convenience.

The density of the areas R, C, and B is determined by the light source 11 shown in FIG.
The balance of the three colors of the printing light emitted from 0 is the R light:
In the case of G light:B light=10:2:1, the density of area R is set to rl and OJ, the density of area G is set to ro and 3J, and area B is set to have no ND filter. Note that the ND filter may be deposited directly on the photosensitive surface 3 of the image sensor 2.

FIG. 4 shows an example of a circuit of an MO3 type image sensor 2 using the pixel configuration shown in FIG. The photoelectric conversion unit 4 is composed of equivalently represented photodiodes, and only the photodiodes 21 to 47 are shown in the drawing. These photodiodes 21 to 47 photoelectrically convert incident light and store the resulting signal charge in a floating capacitor. Here photodiode 2
1.22, 24, 25, 33, 36, 39, 40°45
is for blue, and photodiodes 23, 26, 27,
29, 30, 32, 41, 42.44 are for green,
And photodiode 28° 31 34 35 37
．． 38, 43, 46.47 are for red.

The photodiode 21~23.27~29°33~
35 constitutes a pixel in the first row and first column, and in order to add and extract signal charges of the same color within this pixel, 3
Vertical MOS switches 51 to 53 are provided.

Blue photodiodes 21, 22, and 33 are connected to the source of the blue vertical MOS switch 51.
When the vertical MOS switch 51 is turned on during blue photometry,
Blue vertical line 6 with three signal charges connected to the drain
1 at the same time, and the signal charges within one pixel are thereby added. In addition, the green vertical MOS switch 5
2 sources include green photodiodes 23 and 27.
．． 29 is connected, and when the vertical MOS switch 52 is ON during green photometry, three signal charges are added and taken out from the green vertical line 63. Similarly, when the vertical MOS switch 53 is ONL during red metering, the 3
The signal charges are added and taken out from the red vertical line 62.

The pixels in the first row and second column are photodiodes 24 to 26.
．． It consists of 30-32.36-3 days, and three vertical MO
S switches 54-56 are provided. A vertical line 64 is connected to the drains of these vertical MOS switches 54 to 56.
.about.66 are connected in series. The pixels in the second row and first column are photodiodes 39 to 41, 42 to 44
45 to 47, and three vertical MOS switches 57 to add and extract signal charges of the same color.
~59 are provided. These vertical MOS switches 57-59 are connected to vertical lines 61-63, respectively.

The matrix of photodiodes has one vertical line arranged in each column and one horizontal line arranged in each row. That is, in the first row, the horizontal cotton for blue 7
1 is arranged, a green horizontal line 72 is arranged in the second row, and a red horizontal line 73 is arranged in the third row. Similarly, a blue horizontal line 74 is arranged in the fourth row,
A green horizontal line 75 is arranged in the fifth row, and a red horizontal line 76 is arranged in the sixth row. These signal lines are formed by aluminum vapor deposition, and only one line is required for each column and row, which simplifies the wiring and allows the light-receiving surface of the photodiode to be enlarged by reducing the number of lines.

The first output terminal DI of the vertical scanning shift register 80
The horizontal lines 71 to 73 in the first to third rows are connected to the second output terminal D2, and the horizontal lines 74 to 76 in the fourth to sixth rows are connected to the second output terminal D2.

Horizontal MOS switches 85 to 9 are connected to the vertical lines 61 to 66.
0 sources are connected in series. The horizontal MOS switches 85 to 87 are for taking out the three-color signals of the pixels in the first column, and their gates are connected to the first output terminal F1 of the horizontal scanning shift register 91. Further, the horizontal MOS switches 88 to 90 are for taking out the three-color signals of the pixels in the second column,
Its gate is connected to the second output terminal F2 of the horizontal scanning shift register 91.

A blue output line 93 is connected to the drain of the blue horizontal MOS switch 85.88, and a red output line 94 is connected to the drain of the red horizontal MOS switch 86.89. Similarly, a green output line 95 is connected to the green horizontal MOS switch 87.90. The blue output line 93 is used to extract a valid signal.
A MOS switch 97 for this purpose and a MOS switch 98 for discarding signals read out while the image sensor 2 is periodically driven are connected.

Similarly, two MOS switches 99.
100 is connected, and MOS switches 101 and 102 are connected to the green output line 95.

MOS switch 97°99 to extract valid signals
．． 101 has its drain connected to one common output line 103, and M for discarding unnecessary signals.
The drains of the OS switches 98, 100, and 102 are connected to one reset line 104.

The operations of the vertical scanning shift register 80 and the horizontal scanning shift register 91 are controlled by a scan controller 106, and scanning for each pixel and signal extraction for each color are performed. Since the image sensor 2 is driven at a predetermined cycle, it is necessary to discard unnecessary signals and extract only valid signals. Therefore, the scan controller 106 outputs signals EB, ER, and EC to discard unnecessary signals, turns on the MOS switches 98, 100, and 102, and also outputs signals TS and B to extract valid signals. , T.S.R.

Output TSG, MOS switch 97, 99°101
Turn on. Furthermore, a start signal for starting photometry for each color is input to the scan controller 106. Note that the reference numeral 107 is a pulse generator.

Next, referring to FIG. 5, a photographic printer using the image sensor 2 will be described. The white light emitted from the light source 110 enters the diffusion box 111 through the filter turret 119 for sequential additive color exposure.

The diffusion box 11 is a rectangular cylinder whose inner surface is a mirror surface with diffusion plates attached to both ends thereof, and sufficiently diffuses the white light from the light source 110.

The filter turret 119 divides a disk into five parts in the circumferential direction, and these divided parts are provided with a red filter 122, a green filter 123, a blue filter 124, and an observation hole 12.
5. A shielding part 126 is arranged. This filter turret 119 is rotated by a motor 127,
The rotation of this motor 127 is controlled by a controller 130 via a driver 128. Therefore, by rotating the motor 127 by a predetermined angle, a predetermined filter can be positioned on the printing optical path.

The film holder 112 is arranged above the printing position below the diffusion box tti, and the negative film 113 is attached to the film holder 112.
is set and illuminated with light transmitted through the diffusion box 111. The negative film 113 on the film holder 112 is moved horizontally by manual operation, and a desired frame is set at the print position.

A mirror 131 is provided below the film holder 112 to be inserted into the printing optical path during photometry. Further, a printing lens 118 is arranged below the mirror 131, and the negative image of the set frame is enlarged and formed on the photographic paper 115 at the printing position. Furthermore, the baked lens 1
A shutter 121 whose opening and closing are controlled by a shutter drive unit 120 is arranged below the shutter 18 .

The printing light reflected from the mirror 131 is photometered for each color by a scanner 132. The scanner 132 is
It is composed of an imaging lens 133 and an image sensor 2 equipped with an ND filter 6, and sends trichromatic photometric values of each point read by three-color sequential photometry to a characteristic value calculation section 135. The characteristic value calculation unit 135 calculates characteristic values for each color, such as the average transmitted density, maximum density, minimum density, and average value of a specific area for the entire screen from the photometric values of each point, and calculates these characteristic values for each color from the photometric value of each point. send to Note that a half mirror 136 is arranged between the mirror 131 and the scanner 132, and the reflected light of this half mirror 136 is configured to form an image on a screen 137. Therefore, the frame positions of the negative film 113 in the film holder 112 and the scenes of the frames can be observed. The frame positions and scenes can be observed using a video camera and a monitor CRT in addition to the screen.

The photographic paper 115 is transported by a guide roller 140 and a pair of transport rollers.
41 and conveys one frame from the photographic paper roll 142 to a print position 143.

The rotation of the transport roller pair 141 is controlled by the controller 130. At print position 143, photographic paper 115
A pressure plate 144 and a mask 145 are arranged to ensure flatness. The exposed photographic paper 115 is taken up on a take-up reel 146 and developed by a processor.

When printing with this photo printer, first,
A negative film 113 is inserted into the film holder 112. In the initial state, since the hole 125 of the filter turret l-119 is located in the printing optical path, the negative film 1
13 on the screen 137, print the specified frame!・Set in position.

After monitoring the negative film 113 in the film holder 112 in this way, when a start key (not shown) is pressed for exposure, the controller 130
Rotate the motor 127 to sequentially insert each filter 122 to 124 of the filter turret 119 onto the printing optical path;
Perform red metering, green metering, and blue metering sequentially. During these three-color sequential photometry, the scanner 132 performs photoelectric conversion on the light incident on the image sensor 2 through the ND filter 6, measures the light at each point of the frame for each color, and sends the signal to the characteristic value calculation unit 135. Send it to get the characteristic value for each color. Then, the exposure time is calculated for each color based on the characteristic values obtained by three-color sequential photometry.

Next, the controller 130 retracts the mirror 131 from the printing optical path and rotates the filter turret 119 so that the red filter 122, the green filter 123, .
The blue filters 124 are sequentially inserted into the printing optical path. Then, with the selected color filter entering the printing optical path, the shutter 121 is opened for the exposure time of the corresponding color, so that a color image is printed and exposed on the photographic paper 115 by three-color plane sequential exposure. Thereafter, the controller 130 rotates the conveying roller pair 141 to advance the photographic paper 115 one frame at a time. Next, the filter turret 119 is rotated by a predetermined angle by the controller 130, and the observation hole 125 is rotated by the controller 130.
on the printing optical path. As a result, setting of frames and scenes for the next exposure/printing are confirmed on the monitor screen 137, and then, when the start key is pressed, the above-described printing/exposure is repeated.

Next, three-color sequential photometry using the image sensor 2 will be explained in more detail. The scan controller 106 is
The image sensor 2 is always driven at a predetermined cycle, but during this scan, the signals ER, EC, and EB are "H".
Therefore, the signal charges of the three colors added for each color within the same pixel are transferred to the MOS switch 98, 1 which is in the ON state.
00, 102 from the reset line 104.

After inserting the red filter 122 into the printing optical path, the controller 130 sends a red photometry start signal to the scan controller 106 to start red photometry. During this red photometry, the scan controller 106 sets the signals EB, EC, and TSR to rH in synchronization with the vertical synchronization signal, and sets the signals ER, TSG, and TSB to "L", thereby causing the MO
Turn on the S switches 98, 102, and 99. At the same time, the scan controller 106 manually inputs the shift pulse 162 to the vertical scanning shift register 80 and also inputs the shift pulse 15 to the horizontal scanning shift register 91.
Enter 9. Further, the scan controller 106
A clock pulse 161 is sent to the horizontal scan shift register 91 to perform one horizontal scan, and every time one horizontal scan is completed, a clock pulse 160 is sent to the vertical scan shift register 80 to perform a scan in the vertical direction.

A shift pulse 16 is applied to the vertical scanning shift register 80.
2 is input, the first output terminal DI becomes r
Becomes HJ. Along with this, the horizontal scanning shift register 9
Since the first output terminal Fl of No. 1 becomes "H", the vertical MOS switches 51 to 53 and the horizontal MOS switches 85 to
87 is ONL, and the signal charges accumulated in the photodiodes 21 to 23, 27 to 29, and 33 to 35 of the pixels in the first row and first column are added for each color, and the output lines are separated for each color. 93-95. Here, the red signal enters the common output line 103 through the MOS switch 99 which is in the ON state, and then enters the characteristic value calculation section 13 shown in FIG.
Sent to 5. On the other hand, the blue signal and green signal taken out from the output lines 93 and 95 flow to the reset line 104 through the MOS switch 98102 which is in the ON state.

When the scanning of the pixels in the first row and first column is completed, the horizontal scanning shift register 91 moves the shift pulse by the clock pulse 161, so that the second output terminal F2 becomes r.
HJ, and the color signal of the pixel in the first row and second column is read out. Also in this case, only the red signal is taken out to the common output line 103 via the MOS switch 99.

When the horizontal scanning shift register 91 scans once and reading out the red signal of the pixels in the first row is completed, the scan controller 106 sends the clock pulse 160 to the vertical scanning shift register 80, so that the second output terminal D2 only is rH. In this state, the horizontal scanning shift register 91 scans once as described above, and the signal charges accumulated in each red photoelectric conversion unit belonging to the second row are added within the same pixel. The signal is taken out to the common output line 104. In this way, from image sensor 2, 1
Take out only the red signal for one frame, and then use MOS
Switches 98, 100, and 102 are turned on.

Next, when the green filter 123 is set in the printing optical path, green photometry is started. In this case, since the MOS switches 9B, too, and Lot are in the ON state, the green signal for one frame is taken out from the common output line 103. Similarly, when blue photometry is performed using the blue filter 124, a blue signal for one frame is extracted.

In the above embodiment, the charge accumulation time for each color is the same, but in order to substantially expand the dynamic range of the image sensor, pre-scanning is performed to check the amount of incident light for each color, and the amount of incident light is determined according to the amount of incident light. It is better to automatically determine the charge accumulation time.

In addition, in the above embodiment, the signal charges accumulated in each photoelectric conversion unit are added and extracted for each color within one pixel, but in addition to this, the signals of each photoelectric conversion unit are extracted without addition. It can also be used when taken out as is. Further, in the above embodiments, a MOS type was explained, but it can also be implemented for a CCD type.

Furthermore, in the above embodiment, an ND filter with a different density depending on the spectral luminance characteristics of the light source is arranged in each color area, but the present invention is not limited to this. As in the second embodiment of the present invention shown in FIG.
A mask 153 having an angle of 50,151°152 may be provided. In this case, for example, the balance of the three colors of printing light emitted from the light source of a photo printer is
In the case of R light: G light; B light = 10:2:l, the aperture ratio of the apertures 150, 151, and 152 of each area R, G, and B is A.
R: Aa: Am = 1/10: 1/2
: Set to 14°. Note that the mask 153 can be formed by depositing a mask material on a transparent mask base using photo-etching technology.

Further, in the above embodiment, the color filter 122 to the printing optical path is
~ 124 was inserted by rotating the filter turret 119 by a predetermined angle, but instead of this,
A motor may be used for each filter and these motors may be selectively driven to insert the color filter into the printing optical path.

〔Effect of the invention〕

As explained above, according to the present invention, an ND filter whose density is changed according to the spectral brightness characteristics of the light source of the photoprinting device or a mask whose aperture ratio is changed according to the spectral brightness characteristics is arranged in each color area. From this, the spectral sensitivity of the image sensor can be set according to the light source. This results in
Accurate photometry is now possible, allowing you to create printed photographs with appropriate exposure.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an image sensor and an ND filter of the present invention. FIG. 2 is an explanatory diagram showing the pixel configuration of the image sensor of the present invention. FIG. 3 is an enlarged plan view of a part of the ND filter of the present invention. FIG. 4 is a circuit diagram showing an example of an MO3 type image sensor of the present invention in which signal charges are added and read out for each color within a pixel. FIG. 5 is a schematic diagram showing the configuration of a photographic printer using the image sensor of the present invention. FIG. 6 is a plan view showing a mask in a second embodiment of the present invention. 2... Image sensor - 4... Photoelectric conversion section 4a... Red photoelectric conversion section 4b... Green photoelectric conversion section 4c... Blue photoelectric conversion section 6... ND filters 21 to 47. - Photodiodes 51-59... Vertical MOS switches 150-152... Opening 153... Mask.

Claims (2)

[Claims] (1) Red filter, green filter for exposure during photometry,
In a photometric device for a photo printer that selectively inserts a blue filter into the optical path and sequentially measures each point of an image on a photographic film in three colors, a signal charge is extracted by photoelectrically converting the incident light during red photometry using a red filter. A photoelectric conversion section for red from which a signal charge obtained by photoelectrically converting incident light during green photometry using a green filter is extracted, and a signal charge obtained by photoelectrically converting incident light during blue photometry using a blue filter. An image sensor is provided in which photoelectric conversion parts for blue color from which blue light is extracted are arranged in a matrix, and each photoelectric conversion part of this image sensor is provided with an ND filter having a density value determined for each color according to the spectral luminance characteristics of the light source. A photometric device for a photo printer, characterized in that: (2) Red filter, green filter for exposure during photometry,
In a photometric device for a photo printer that selectively inserts a blue filter into the optical path and sequentially measures each point of an image on a photographic film in three colors, a signal charge is extracted by photoelectrically converting the incident light during red photometry using a red filter. A photoelectric conversion section for red from which a signal charge obtained by photoelectrically converting incident light during green photometry using a green filter is extracted, and a signal charge obtained by photoelectrically converting incident light during blue photometry using a blue filter. An image sensor is provided in which blue photoelectric conversion parts from which blue light is extracted are arranged in a matrix, and a mask having an aperture ratio determined for each color according to the spectral luminance characteristics of the light source is arranged in each photoelectric conversion part of this image sensor. A photometric device for photo printers that is characterized by: