JPH07303167A - Transparent original reader and photoelectric conversion device - Google Patents

Abstract

PURPOSE:To correct color unbalance with respect to video information of a transparent original by connecting a dimmer to adjust a luminous quantity of each color to a light source so as to make luminous quantity balance of each color equal to each other at the input side of a photoelectric converter. CONSTITUTION:When a transparent original 7 recording a read image is a positive film, a white reference board is inserted between light sources 1 to 3 and a photoelectric converter 8 in place of the original 7 prior to the reading, and when the original is a negative film, a black reference board is used so that the transmitted quantity of the color image whose color is unbalanced is made equal for three R, G, B colors. That is, The reader is adjusted based part of video information having a highest transmittance. Thus, a comparator 9 gives a command so as to reduce the luminous quantity to a dimmer 4 when a red luminous quantity is larger tan an object quantity, for example and increases the luminous quantity when smaller. The operation is applied also to other colors and the converter 8 is used to confirm the color balance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent original reading device used for reading video information from a transparent original on which a color image is recorded, and converting video information input as an optical signal for each color into an electric signal. The present invention relates to a photoelectric conversion device that can be used in, for example, a transparent original reading device.

[0002]

2. Description of the Related Art For the purpose of electrically processing an object recorded on a positive film, a negative film or the like, a transparent original reading device using such a film as a transparent original has been conventionally used. In this transparent original reading device, an object on which an image to be read is recorded is sandwiched between a light source and a photoelectric conversion device. The image is input to the photoelectric conversion device as an optical signal, the image information thereof is converted into an electric signal, and the image data is taken out. This video data is processed by a computer or stored and then reproduced by a monitor device or the like.

A conventional transparent original reading device uses a fluorescent lamp or a halogen lamp as a light source for irradiating a transparent original, and a CCD or an image pickup tube is used as a photoelectron converting device. This type of transmissive light source has a fixed spectral distribution and a constant amount of light. In addition, most types of originals to be read were positive films. In order to input a color image from a transparent original as video information by such a device, red, green, and blue (R, G, B) filters are used, and the video information for each of the three colors is sequentially converted into a photoelectric signal. The image data is input to the device, and as a result, a plurality of monochrome image data is created.

By the way, in this type of reading apparatus, when a color image whose color balance is lost, such as a negative film in which a transparent original is masked with an orange, is input as video information, it is directly converted into video data. Also,
It cannot be reproduced as a video with a good S / N ratio. In order to accurately reproduce each color from the image information of the transparent original with the color balance lost, three scans are performed for each transparent original, and red, green, and blue (R, G, B) are scanned respectively. Image information for each single color must be input to the optoelectronic conversion device and converted into an electric signal with a storage time corresponding to each light amount. On the other hand, in order to perform a color image reading operation at high speed, there is also a reading device having a photoelectric conversion device corresponding to each of R, G, and B in the photoelectric conversion device. Instead of extracting video data for each single color,
Video data corresponding to a color image can be output at one time by simultaneously reading the three colors of R, G, and B. Moreover, even with image data converted into electric signals with the color balance lost, if digital gradation correction, for example gamma correction, is applied,
The reproduced image appears to the human eye as a normal image.

[0005]

However, in the method of performing gradation correction by gamma correction or the like on the read image data, the color balance is improved, but the following problems also occur. That is, the photoelectric conversion device has, for example, 8 bits, 2
Even if it has the capability of 56 gradations, gradation correction occurs in the video signal if gradation correction is performed on the digital data converted into an electric signal while the color balance is lost. Therefore, it is unavoidable that the image data is deteriorated as compared with the capability of the photoelectric conversion device.

When R, G, and B photoelectric conversions are performed at different storage times according to the quality of the recorded color image, the original scanning is repeated at different times for each color of the color image. Therefore, there is a problem that the reading efficiency of the transparent original reading device is lowered as a result.

As described above, the conventional apparatus for reading the image information from the transparent original whose color balance is lost has a problem that the image data having a good S / N ratio cannot be efficiently obtained as it is.

The present invention has been made in order to solve the above problems. A first object of the present invention is to make it possible to take out high-quality video data even for a transparent original whose color balance is lost. A document reading device is provided.

A second object of the present invention is to provide a photoelectric conversion device capable of removing the loss of the color balance of a video signal read by scanning a document once.

[0010]

According to a first aspect of the present invention, there is provided a transparent original reading apparatus in which a plurality of light sources that can be independently dimmed are individually dimmed by a dimming device. The control means for controlling the light source is provided so that the magnitudes of the electric signals for the respective colors of the converted video data are in the same range.

According to a second aspect of the present invention, one of the plurality of light sources is a dimmable light source corresponding to the wavelength transmission characteristic of the transmissive original, and the other light sources have a fixed amount of light and are of mixed colors. By using the light source, only one light control device is used in the transparent original reading device according to the first aspect.

According to a third aspect of the present invention, a plurality of light sources are light sources whose light amounts are fixed to a constant amount, and which are capable of canceling out the average base amount of the transparent original, and a light source of mixed colors. By replacing with, the control means used in the transparent original reading device according to the first and second aspects is also unnecessary.

According to a fourth aspect of the present invention, there is provided the transparent original reading device according to the first to third aspects, wherein the correction amount of the color balance between the optical signals for each color is based on the video signal converted by the photoelectric conversion means. Is used, and a photoelectric conversion device provided with control means for feedback-controlling the amplification factor of the amplification means for amplifying the video signal for each color is used.

According to a fifth aspect of the present invention, in the transparent original reading device according to the first to third aspects, the photoelectric signal converting means for converting the image information into an electric signal has a fixed cycle of the optical signal accumulating period for each color. The photoelectric conversion device is provided with a means for internally setting and a means for outputting, as a video signal, only an electric signal corresponding to the optical signal input during the set accumulation period.

In the photoelectric conversion device according to the sixth aspect, based on the video signal converted by the photoelectric conversion means,
There is provided control means for determining the correction amount of the color balance between the optical signals for each color and for feedback-controlling the amplification factor of the amplification means for amplifying the video signal for each color.

According to a seventh aspect of the present invention, the opto-electronic conversion means for converting video information into an electric signal is provided with a means for setting an optical signal storage period for each color within a fixed cycle and a set storage period. And a means for outputting only an electric signal corresponding to the inputted optical signal as a video signal.

[0017]

In the transparent original reading device according to the first aspect of the invention, since the light source side is connected with the light control device for adjusting the light amount of each color, the light amount balance of each color is balanced on the input side to the photoelectric conversion device. Set equal to each other. Therefore, the image information of the transparent original to be read can be corrected in advance for the loss of color balance.

According to the second aspect of the invention, the light sources of the colors important for the color image are set on the light source side and are equal to each other on the input side of the apparatus. Therefore, the image information of the transparent original to be read can be corrected in advance for the loss of color balance.

According to the third aspect, the control means used in the transparent original reading apparatus according to the first and second aspects is also unnecessary, so that the color balance of the transparent original of a limited type is further disturbed. The reading device can be corrected at low cost.

According to a fourth aspect of the present invention, in the photoelectric conversion device, the correction amount of the color balance is obtained using the data based on the reference original or the reference data read from the read original, and the gain of the photoelectric conversion element on the light receiving side is obtained. The correction is performed and the video data is output.

According to a fifth aspect of the present invention, the storage time of the photoelectric conversion element is set for each single color so that the intensity of the electric signal of each color is equalized, and the sampling period of each color is synchronized to output the video data. I have to.

In the photoelectric conversion device according to the sixth aspect, the correction amount of the color balance is obtained using the data based on the reference original or the reference data read from the read original, and the gain correction of the photoelectric conversion element is performed on the light receiving side. Is performed.

In the photoelectric conversion device according to the seventh aspect, the accumulation time of the photoelectric conversion element is set for each single color to make the intensities of the electric signals of the respective colors equal and to synchronize the sampling periods of the respective colors.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The first to third embodiments describe the transparent original reading device of claims 1 to 3, respectively, and the fourth and fifth embodiments describe claims 4 and 5, respectively.
The photoelectric conversion devices used in the transparent original reading device of the above are described. However, as described in claims 6 and 7, these photoelectric conversion devices can be used as independent devices to achieve a predetermined effect. It plays.

Embodiment 1 FIG. 1 shows an embodiment of a transparent original reading device using a light control device. In this example, from the color image, red, green,
In order to separate and extract the video signals of the three colors of blue, 3
A color light source is prepared, and the light amount balance of three video signals is controlled at the stage of receiving light.

In the figure, 1 is a red light source, 2 is a green light source, 3
Is a blue light source, which is connected to the dimmers 4, 5 and 6, respectively. Reference numeral 7 is a transparent original on which an image to be read is recorded, and 8 is a photoelectric conversion device. The transparent original 7 includes light sources 1, 2, and 3 of three colors and a photoelectric conversion device 8.
The light that is sandwiched between and and transmitted therethrough is input to the plurality of photoelectric conversion elements of the photoelectric conversion device 8 as image information. These photoelectric conversion elements include three sets of light receiving elements that operate independently by the optical signals of red, green, and blue for each dot position.

The photoelectric conversion device 8 converts the input image information into an electric signal for each color corresponding to the amount of received light and outputs the electric signal, and a comparator in which a target amount for each color is set. 9, 10 and 11 are connected. 12
Is an operation panel for setting equal target amounts in the comparators 9, 10 and 11, respectively. The comparators 9, 10 and 11 are respectively connected to the dimming devices 4, 5 and 6 of the red light source 1, the green light source 2 and the blue light source 3 to form feedback loops for controlling the intensities of the three light sources.

Next, the operation of the first embodiment will be described. In this transparent original reading device, the same and independent feedback loop is formed for each of the three image data of red, green, and blue to be read.
Regarding the above, the control operation of the intensity will be described.

When the transparent original 7 on which the image to be read is recorded is a positive film, a white reference plate is used in place of the transparent original 7 before the reading.
3 and the photoelectric conversion device 8. Conversely, when reading an image from a negative film transmissive original, a reference plate representing black is used. In order for the amount of transmitted light of the color image with the color balance lost to be the same for each of the three colors R, G, and B, the transparent original reading device may be adjusted based on the video information portion having the highest transmittance. . that way,
When reading a series of color images of a transparent original, only the reference colors included in the original can be reproduced as at least accurate video data. In other words, if you use the reference plate,
It is possible to feed back the base amount, which is included in the transparent original document on average, to the light source side. Similarly, when using a negative film with an orange mask as a transparent document, even if the color balance itself is broken, if there is no significant difference in the break between a series of documents, the orange mask used when creating the document is used. Can be used as a reference plate.

Of course, in general, it is possible to use the transparent original 7 itself whose color balance is lost as a color adjustment reference,
In that case, a reference plate or the like is not required. However, when reading a color image from each of a series of transparent originals, it is necessary to reset the target amount of the video information contained in each transparent original by the operation panel 12.

The electric signal output as the amount of red light is compared with the target amount set in the comparator 9. This target amount needs to be set as an appropriate value in correspondence with the subsequent device that processes the output of the transparent original reading device, and basically, it should be the same value for the three colors. .

When the amount of red light is larger than the target amount, the comparator 9 gives a command to the light control device 4 to decrease the amount of light. On the contrary, when the amount of red light is small, the amount of light is changed. It gives a command to increase. As a result, the intensity of the red light source 1 is controlled so that the red electric signal output from the photoelectric conversion device 8 becomes equal to the set target amount.

Such an operation is performed for other colors at the same time, and whether the signal amounts of the three colors are equal is determined by, for example, reproducing the video data of the photoelectric conversion device 8 on the monitor and checking the color balance. I can confirm. Alternatively, the outputs of the comparators 9 to 11 may be fixed after a fixed time. After that, the transparent original 7 is replaced with the light source 1 to the reference plate.
It is sandwiched under 3 and is scanned by the photoelectric conversion device 8.

As a result, when the transparent original 7 uses a negative film with an orange mask, the spectral component of the base of the orange mask is removed from the optical signal of each color of the image information, and the photoelectric conversion device 8 is obtained. The amount of light input to can be balanced among the three colors.

Embodiment 2 FIG. 2 shows another embodiment of a transparent original reading device using a light control device. This Example 2 is different from the above Example 1,
The light quantity balance of three video signals is controlled by one light source capable of dimming.

In the figure, 21 is a monochromatic light source selected by the transparent original 7 on which an image is recorded, 22 is a mixed color light source whose intensity does not change, and the monochromatic light source 21 is connected to a light control device 23. Reference numeral 7 denotes a transparent original serving as an object to be read, which is, for example, an orange masked negative film. Reference numeral 8 denotes a photoelectric conversion device, which converts the input image information into an electric signal for each color corresponding to the amount of received light and outputs the same, as in the case of the first embodiment. A dimming amount calculation device 24 is connected to the photoelectric conversion device 8, and the dimming amount calculation device 24 controls the dimming device 23.

Next, the operation of the second embodiment will be described. The transmissive original 7 is a negative film masked with an orange here, and the transmissive characteristic of this original has a wavelength characteristic that the transmissivity of red light is generally high and the transmissivity decreases as the color becomes blue. . Therefore, the color of the monochromatic light source 21 is selected to be blue, which is the complementary color of the orange mask used for the transparent original 7.

First, instead of the transparent original 7, a reference plate representing orange as a reference color is placed at the reading position of the transparent original reading device. The light from the two light sources 21 and 22 that has passed through the reference plate is input to the plurality of photoelectric conversion elements of the photoelectric conversion device 8. The photoelectric conversion element converts the optical signals of red, green, and blue for each dot position into electrical signals, and these electrical signals are input to the dimming amount computing device 24 whose target value is set. . Then, the light control device 23 is controlled so that the signal amounts of the three colors are as close to the target value as possible.

For example, when the blue light signal input to the dimming amount calculation device 24 is smaller than the target value, the dimming device 23 is controlled so as to increase the intensity of the blue color corresponding to the complementary color of the monochromatic light source 21. .

When the type of the transparent original 7 read by the transparent original reading device is changed, the color of the monochromatic light source 21 must be changed to another color. That is, it is necessary to select an appropriate color light source suitable for the type of transparent original. However, from the beginning, the monochromatic light source 21
If, for example, is replaced with a mixed color light source including blue and red, another type of transparent original can be handled to some extent.

The monochromatic light source 21 used here is used.
Means that the spectral distribution of the light source has only one peak value, and that the color mixture light source 22 has a plurality of peak values. Therefore, if one is the monochromatic light source 21 and the other is the mixed color light source, all the colors of the transparent original 7 can be extracted as optical signals. In this way, the output of the light control device 23 can be fixed so that the signal amounts of the three colors are equal. After that, the transparent original 7 is placed under the light sources 21 and 22 in place of the reference plate, and is scanned by the photoelectric conversion device 8.

As a result, the base portion of the orange mask is removed from the transparent original using the negative film on which the orange mask is applied, and the light quantity input to the photoelectric conversion device 8 becomes balanced among the three colors.

Embodiment 3 FIG. 3 shows an embodiment of a transparent original reading device which does not use a light control device. The third embodiment is different from the first and second embodiments in that the light amount balance of three video signals is controlled by one light source adjusted to some extent.

For example, when the transparent original to be read is limited to a negative film with an orange mask, it is not necessary to significantly change the color balance of the light source. That is, since a light source capable of removing the basic amount of base is sufficient, this embodiment is the dimming device 2 of the second embodiment.
This corresponds to the case where the dimming amount according to 3 is set to a fixed value.

In the figure, 31 is a monochromatic light source selected by the transparent original 7 on which an image is recorded, and 32 is a white mixed color light source, the intensity of which does not change. The transparent original 7 as the reading target is, for example, an orange masked negative film. Reference numeral 8 denotes a photoelectric conversion device, which converts the input image information into an electric signal for each color corresponding to the amount of received light and outputs the same, as in the case of the first embodiment.

In this case, the intensity of the monochromatic light source 31 that emits light of the complementary color of the orange mask is fixed from the beginning, and no dimming device is required. With only two light sources 31, 32,
This is because it is possible to compensate for the decrease in the blue light signal of the transparent original 7. Therefore, in this embodiment, the cost of the light source is further reduced, the color balance is improved, and the gradation skip can be prevented. Example 4

The fourth embodiment is an optoelectronic conversion device which, when a video signal lacking color balance is input, electrically adjusts the color balance of the video data and then outputs the data. If this photoelectric conversion device is used in combination with the transparent original reading device of the above-described first to third embodiments, the color balance of the output image data can be further improved, and the gradation skip of the color data and the S / N ratio can be improved. Deterioration can be reliably prevented.

FIG. 4 is a block diagram showing a part of the structure of the photoelectric conversion device. 41, 42 and 43 are gain control amplifiers provided corresponding to the photoelectrically converted electric signals of the respective colors, and 44, 45 and 46 are gain controllers.

Next, the operation of the fourth embodiment will be described. A video signal obtained from a transparent original whose color balance is lost has a different input level for each color from the gain control amplifier 4
1, 42 and 43. Therefore, the input level of the reference electrical signal (reference signal) for each color is sampled by scanning the reference document surface from the reference document or the transparent document to be read in advance. Controller 44, 45
And 46. Next, the video data photoelectrically converted from the transparent original is supplied to the gain control amplifiers 41 and 4,
The gains and base amounts of the gain control amplifiers 41, 42 and 43 controlled by the gain controllers 44, 45 and 46 are determined on the basis of the control information stored in 2 and 43 and stored previously. The control by this controller simply needs to control the maximum value and the minimum value of the electric signal input to the amplifier so that they match for each color on the output side of the amplifier.

As described above, since the color balance of the image data is electrically adjusted by correcting the gain of the photoelectrically converted analog electric signal for each color, unlike the gradation correction performed digitally, The input signal range of the A / D converter can be expanded to the entire range. as a result,
According to this photoelectric conversion device, it is possible to convert image information from a document whose color balance is lost into digital data without gradation skip.

In the above description, the amplification factor of the analog amplifier such as the gain control amplifier is variably controlled, but the output can be equalized by digitally feedback controlling the reference voltage of the A / D converter. be able to. In that case, the control information such as the input level of the reference signal can be stored in a video memory in the subsequent stage. In addition, the gain controller 4
The control information stored by 4, 45 and 46 may be only analog peak hold of the electrical signals of each color.

Fifth Embodiment A fifth embodiment is a photoelectron conversion device having a function of varying the light accumulation time in the image pickup device itself such as CCD. Generally, in photoelectric conversion, a constant scanning time is set to read an image. In the fifth embodiment, when scanning an image at a sample period according to the characteristics of the photoelectric conversion element, it is noted that the longer this time is, the video data can be obtained as a large electric signal even with weak light. .

In this photoelectric conversion device, the image information from the color image is photoelectrically converted by setting different light accumulation times for the respective colors to equalize the intensities of the electric signals of the respective colors to be output, and the samples of the respective colors are sampled. The cycle is synchronized. Therefore, if this photoelectric conversion device is used in combination with the transparent original reading device of the above-described first to third embodiments, the color balance of the output video data can be further improved, and the gradation jump of the color data and the S / N ratio can be improved. Deterioration can be reliably prevented.

FIG. 5 is a diagram showing a CCD array corresponding to one color of the photoelectric conversion device. The CCD array 51 receives only the red light signal of the image information transmitted and input from the transparent original, and the light receiving element corresponding to each dot is stored in the register 52 that holds the converted electric signal. Connected. Reference numeral 53 is an optical signal storage time control circuit, which outputs an end pulse EPr to the register 52 at a timing described later, and outputs end pulses EPg and EPb to a register of another color not shown.

Reference numeral 54 is a data discharge section, which is connected to each dot of the CCD array 51 and is supplied with a clock pulse CLK. An A / D converter (not shown) or the like is connected to the register 52, and a red digital video signal is read out. From the CCD array corresponding to the other color similarly configured, the optical signal received there is converted into a video signal and read out, and these are recorded as video data.

Next, the operation will be described with reference to FIG. FIG. 6 is a time chart showing the accumulation time for each color set in one sampling period T. CC for receiving red light signal
In the D array 51, the end pulse EPr supplied within the sampling period T defined by the clock pulse CLK.
Thus, the received light data accumulated during that period (data accumulation period T1r) is transferred to the register 52. Then, the received light data accumulated in the remaining time (T2r) after the end pulse EPr is input to the register 52 is forcibly cleared by the data discharge unit 54 in synchronization with the next clock pulse CLK.

Similarly, the end pulse EPg is also supplied to the CCD array receiving the green light signal within the sample period T defined by the same clock pulse CLK. Here, in the illustrated example, since the intensity of the blue optical signal is the smallest, the sample period T is set as the data storage time T1b as it is, and the received light data accumulated during that period is transferred to the corresponding register.

In this optoelectronic conversion device, CCs provided for different colors by the end pulses EPr, EPg, etc. generated from the optical signal storage time control circuit 53 at specific timings.
Since the sample period T of the D array is divided into the data accumulation period T1 and the remaining time T2, the color images of R, G, and B colors can be read by one scan while synchronizing the sampling periods of the respective colors. Then, by setting the storage period for each color so that the electrical signals for each color are equal to each other, it is possible to output video data with good color balance and S / N ratio.

[0059]

Since the present invention is constructed as described above, it has the following effects.

In the transparent original reading device according to the first aspect, even when the color balance of the transparent original is lost, the image information in which the intensity of the optical signal of each color is adjusted to a constant range is always supplied to the photoelectric conversion device. it can. Therefore, it is possible to obtain video data with stable color balance, no gradation skip, and good S / N ratio. The transparent original reading device according to the second and third aspects also has the same effect.

Particularly, in the apparatus according to the second aspect, only the light source of the color that needs to be particularly variable for reading the transparent original is dimmable, and the light source itself has a simple structure. Therefore, the cost of the device can be reduced, and the dimming operation can be facilitated.

Further, since the apparatus of claim 3 does not need a light control device at all, when the image quality of the desired transparent original is limited, the light source can be constructed to be cheaper. it can.

In the apparatus according to the fourth aspect, the adjustment by light adjustment on the light source side is not sufficient, and the color balance of the document input to the photoelectric conversion element is lost, and therefore the intensity of each color varies. Even when input as an optical signal, it is possible to always convert into video data in which the intensity of the electric signal for each color is adjusted within a certain range. Therefore, it is possible to stabilize the color balance without impairing the capability of the photoelectric conversion device, and it is possible to obtain image data without gradation skipping.

Further, in the apparatus of claim 5, since the photoelectric conversion is executed by setting the accumulation time according to the image quality of the recorded color image, the transparent original is repeated in the same cycle without lowering the reading efficiency. Can be scanned.

In the photoelectric conversion device according to the sixth aspect, since the gain correction is performed in the input stage of the light receiving section,
Even if an optical signal having a different intensity for each color is input, the intensity of the converted electric signal of each color is constantly adjusted within a certain range. Therefore, even if the color balance of the original document is lost and therefore the light signals of different intensities are input for each color,
It is possible to always convert the intensity of the electric signal for each color into image data in which the intensity is adjusted within a certain range. Since this device can obtain the same effect even when used alone as a photoelectron conversion device, it can be applied not only to the reading of transparent originals but also to the reading of reflective originals.

Further, according to the seventh aspect, since the accumulation time of the optical signal is adjusted, even if the optical signal having the different intensity for each color is input, the intensity of the converted electric signal of each color is always calculated. It can be adjusted within a certain range. Therefore, even if the image information having the color imbalance is read, it can be efficiently converted into the video data having a good S / N ratio. Since this device can obtain the same effect even when used alone as a photoelectron conversion device, it can be applied not only to the reading of transparent originals but also to the reading of reflective originals.

[Brief description of drawings]

FIG. 1 is a block diagram of a transparent original reading device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a transparent original reading device showing a second embodiment of the present invention.

FIG. 3 is a block diagram of a transparent original reading device showing a third embodiment of the present invention.

FIG. 4 is a block diagram of a photoelectric conversion device showing a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a photoelectric conversion device showing a fifth embodiment of the present invention.

FIG. 6 is a timing chart showing an operation of the fifth embodiment of the present invention.

[Explanation of symbols]

1-3 light sources, 4-6 dimmers, 7 transparent originals, 8
Optoelectronic converter, 9-11 comparator.

Claims (7)

[Claims] 1. A transparent original reading device for inputting a color image recorded on a transparent original as video information and reading the image as video data of the transparent original, wherein a plurality of light sources independently dimmable, A light control device for controlling light control of each of the light sources, a photoelectric conversion device to which image information is input from the transparent original sandwiched between the light sources, and a color of image data converted by the photoelectric conversion device. A transparent original reading device, further comprising: a control unit that controls the light control device so that the magnitudes of different electric signals are in the same range. 2. A transparent original reading device for inputting a color image recorded on a transparent original as video information and reading it as video data of the transparent original, wherein a spectral distribution corresponding to a wavelength transmission characteristic of the transparent original. A dimmable light source, a mixed color light source with a fixed amount of light, a dimming device for dimming the dimmable light source, and the transparent original sandwiched between the light source. A photoelectric conversion device to which image information is input from, and a control unit that controls the light control device such that the magnitudes of the color-dependent electric signals of the image data converted by the photoelectric conversion device are in the same range. And a transparent original reading device. 3. A transparent original reading device for inputting a color image recorded on a transparent original as video information and reading it as video data of the transparent original, wherein a spectral distribution corresponding to a wavelength transmission characteristic of the transparent original. A dimmable light source having a light source, a mixed color light source having a fixed amount of light, and a light source having a fixed amount of light capable of canceling out the average base amount of the transparent original. A photoelectric conversion device to which image information is input from the transparent original sandwiched between the light source and an electric signal for each color of image data converted by the photoelectric conversion device have the same range. And a control means for controlling the light control device so that the transparent original reading device is provided. 4. The transparent original reading device according to claim 1, 2 or 3, wherein the photoelectric conversion device converts image information input as an optical signal for each color into an electrical signal for each color. A photoelectric conversion unit for converting, an amplification unit for variably amplifying the electric signal converted by the photoelectric conversion unit for each color, and a correction amount of the color balance between the optical signals based on the converted electric signal is determined, A transparent original reading apparatus comprising: a control unit that feedback-controls an amplification factor of the amplification unit. 5. The transparent original reading device according to claim 1, 2 or 3, wherein the opto-electronic converter converts the video information input as a color-specific optical signal at regular intervals by color. A photoelectric conversion means for converting into an electric signal, and a means for setting the optical signal accumulation period for each color within the fixed period so that the electric signals for each color in the photoelectric conversion means are equal to each other, A transparent original reading device comprising: means for outputting, as image data, only an electric signal corresponding to an optical signal input during the accumulation period. 6. A photoelectric conversion means for converting image information inputted as an optical signal for each color into an electric signal for each color, and an amplification means for variably amplifying the electric signal converted by the photoelectric conversion means for each color. A photoelectric conversion device, comprising: a control unit that determines a correction amount of color balance between the optical signals based on the converted electric signal and feedback-controls an amplification factor of the amplification unit. 7. A photoelectric conversion means for converting image information input as a color-specific optical signal at regular intervals into color-specific electric signals and a color-specific electric signal in the photoelectric conversion means are equal to each other. As described above, there are provided means for setting an optical signal accumulation period for each color within the range of the constant period, and means for outputting only an electric signal corresponding to the optical signal input in the accumulation period as video data. A photoelectric conversion device characterized by.