JPH07264488A - Electronic image pickup device - Google Patents

Abstract

PURPOSE:To obtain high sensitivity and high dynamic range characteristic by adding an offset level to an output of an image sensor corresponding to high sensitivity or low sensitivity relatively. CONSTITUTION:A chart having gradation whose contrast is continuously changed is used and a position corresponding to a border is searched and marked at an incident light quantity when an output of a CCD 1B is '00001' and suppose that an output of a CCD 1A is '1111100', then a value '0000100' adding '0000001' to '0000011' resulting from subtracting '1111100' from '1111111' is calculated as an offset and after the offset '0000100' is given to a D/A converter, from which an analog voltage is fed to an offset adder section, in which the voltage is added to output data of the CCD 1A, then two characteristic curves are jointed continuously to correct a gradation step difference.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to electronic imaging devices,
In particular, the present invention relates to an electronic image pickup device in which the dynamic range is comprehensively expanded by using a plurality of sensors as photoelectric conversion elements.

[0002]

2. Description of the Related Art For example, as an electronic image pickup device for printing plate making, a device for moving a film original with respect to a line sensor such as a CCD to input an image of the film original has been put into practical use. FIG. 15 shows a schematic diagram of an electronic imaging device of this kind.

Light from a light source 100 is applied to a film original 101 mounted on a stage table 108 that is moved in the direction of the arrow by a drive stepping motor 109. The transmitted light of the film original 101 is formed by the imaging lens 102.
After passing through, the amount of light is adjusted by the diaphragm 103 and an image is formed on the CCD 1 as an image sensor. First, after performing predetermined exposure at the initial position (start position of image capturing), the photoelectrically converted charges are transferred to the signal processing circuit by the shift register of the CCD, and at the same time moved to the predetermined position by the drive stepping motor, and after movement, the same operation is performed. Continue operation. In this way, one electronic image is formed after various process processes of outputting the image up to the image capturing end position and arranging it in the subsequent stage.

[0004]

As described above, in the conventional electronic image pickup device, the device using the CCD line sensor is widely used because of its small size and easy handling. There was also a problem. That is, C
Considering the range in which the linearity of each pixel output is uniform in the dynamic range of the CD alone, the range that can be effectively used in actuality is about 40 dB, and image input using such a sensor is performed. If you do, it will appear as small streaky noise in the very dark area.

In the 1993 issue of the Seller Graphics Research Group (P28-29), a method of eliminating the non-linear region by bias light by introducing weak light from a separately provided light source is proposed. However, this is a method of using the linear area of the CCD, and does not make up for the lack of dynamic range.

On the other hand, as an electronic image pickup device for plate making of printing, a density range of 3.5 or more (70 dB or more) is desired from the film reproduction range. Therefore, in an electronic image pickup apparatus that requires high quality, a sensor having a high dynamic range in the element output itself such as a photomultiplier is used, which is a cause of limiting the usable range of the CCD that is easy to handle.

An object of the present invention is to provide an electronic image pickup device having high sensitivity and high dynamic range characteristics.

[0008]

In order to solve the above-mentioned problems, an electronic image pickup device according to the present invention has a plurality of image sensors having different sensitivity characteristics related to photoelectric conversion and a plurality of image sensors each having the same sensitivity characteristic. The time phase of the photoelectric conversion output corresponding to the image position is substantially matched, and the overall photoelectric conversion characteristics are shared by each of the characteristic areas corresponding to each other by the plurality of image sensors, effectively by each individual image sensor. An electronic image pickup device comprising: a dynamic range expanding unit for obtaining a dynamic range related to the photoelectric conversion characteristic wider than that of a plurality of image sensors, wherein the plurality of image sensors have high and low sensitivity. The sensitivity of each person is set so as to form a sequential sensitivity series according to the degree of While fixing the upper limit or the lower limit of the dynamic range in the overall photoelectric conversion characteristics to a predetermined upper limit or lower limit for the linear region of the image sensor output located on the lowest or highest sensitivity side in the sequential sensitivity series, When allocating a share for each of the corresponding characteristic regions by the plurality of image sensors, relatively low sensitivity with respect to the sequential sensitivity series with respect to adjacent share regions to be shared by the outputs of the image sensors, or Regarding the linear area of the image sensor output corresponding to the high sensitivity side Regarding the linear area of the image sensor output relatively corresponding to the high sensitivity or low sensitivity side with respect to the above-mentioned sequential sensitivity series with respect to the output level set to the predetermined lower limit or upper limit The relative values are set so that the output levels set as the predetermined upper and lower limits match. It is configured to add an offset level to the image sensor output corresponding to the high sensitivity or low sensitivity side.

Here, the dynamic range enlarging means adds the offset level to the adjacent sensitivity sharing areas which are to be shared by the outputs of the image sensors, and is relatively related to the sequential sensitivity series. A predetermined first binary digit sequence is associated with an output level that is a predetermined lower limit or upper limit for the linear region of the image sensor output corresponding to the low sensitivity or high sensitivity side, and is relative to the sequential sensitivity sequence. And a predetermined second upper limit or lower limit for the linear region of the image sensor output corresponding to the high sensitivity side or the low sensitivity side and the predetermined second binary digit sequence are associated with the output level. Apply the difference value calculation means to obtain the difference corresponding value as binary data by the binary digit series. Comprising means for forming the operation for the offset level added based on the output of the difference value calculation unit.

[0010]

According to the present invention, a plurality of image sensors having different sensitivity characteristics are combined with each other by the digital data synthesizing process in which the time phases of the photoelectric conversion outputs corresponding to the same image position are substantially matched to each other. In order to obtain a wide dynamic range, the plurality of image sensors add an offset level so that the output levels at the boundaries of the sequential sensitivity series match.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram of a pre-signal processing system in an electronic image pickup device according to the present invention. Image signals from the CCDs 1A and 1B, which are driven in the sub-scanning direction of the arrow direction and whose sensitivity is adjusted by an ND filter described later,
In the CDS (correlated double sampling) units 2A and 2B and the clamp units 3A and 3B, well-known sampling and clamping processes are performed, and then gains are adjusted by the gain adjusting units 4A and 4B. The offset addition unit 5A adds the offset signal from the D / A converter 9 described later to the output signal from the gain adjustment unit 4A and outputs the result. The gain adjusting units 4A and 4B and the offset adding units 5A and 5B are C
The continuity and dynamic range adjustment when connecting two image signals obtained from CDs 1A and 1B are performed.

The output signal from the offset adder 5A is
After being converted into 7-bit digital data by the A / D converter 6A, the delay unit 7 delays the time T corresponding to the deviation of the capture time due to the difference in the arrangement position between the CCDs 1A and 1B.
Is delayed and output. In addition, the A / D converter 6
B converts the output signal from the offset addition unit 5B into digital data and outputs it.

In this embodiment, CC as a line sensor
In order to solve the problem of linearity of D, a plurality of CCDs having different sensitivities are used, and the output from the CCD whose linearity is secured is selected and used for each range of the incident light amount. For example, as shown in FIG. 5A, three CCDs having different sensitivity characteristics are arranged, and as shown in FIG. 5B, in the low illuminance range R1 where the incident light amount is small, CC
Although the sensitivities of D2 and CCD3 are not linear, CCD1 has linearity. In the range R2,
It is not linear except for CCD2, and CC in range R3
It is not linear except D3. Therefore, in the incident light amount ranges R1, R2, and R3, CCD1, CCD2
It is possible to selectively output the outputs of the CCD 3 and the CCD 3 and process the outputs to obtain one linear sensitivity characteristic.

There are various methods for changing the sensitivity of the photoelectric conversion of the sensor. For example, depending on the manufacturing process, C
There are methods in which the photoelectric conversion characteristics of the photodiode portion of the CD are made different for each sensor, the gain of the amplifier for amplifying the output of the CCD is made different, or both of them are combined. The sensitivity can also be controlled by changing the shutter speed of each sensor to control the exposure time, or by changing the characteristics of the ND filter provided in front of the sensor for attenuating the light amount for each sensor. The sensitivity of the sensor is preferably set so as to be proportional to 1/2 ⁿ in terms of digital processing. In the present application, the term “image sensor” is a general term for the functional units that have undergone sensitivity change processing by the various means described above. still,
In this specification, an "image sensor" in this sense is simply referred to as a CCD.

In this embodiment, the outputs of both sensors are combined using two CCDs whose sensitivity is set to 1 and 1/2 ⁷ . FIG. 3 is a diagram for explaining a method of combining image data from the two CCDs 1A and 1B. CCD1
A is a high sensitivity sensor and CCD 1B is a low sensitivity sensor.

The signal processor 8 in FIG. 1 is a CCD 1A.
And 7-bit image data corresponding to the image signal from the CCD 1B are received, both data are combined to obtain 14-bit data, and the dynamic range is expanded. This composition
As shown in FIG. 3, 7 from the low sensitivity sensor 1B
The bit data is the upper 7 bits of the 14-bit output data, and the 7-bit data from the high sensitivity sensor 1A is the lower 7 bits.
Done as a bit. This synthesis can be easily performed by bit shift synthesis.

The signal processing section 8 is constructed as shown in FIG. The output corresponding to CCD 1A from the delay unit 7 is added to the adder 8
At 1A, the offset is added to the offset stored in the correction ROM 82A to correct the variation for each pixel. The addition output from the adder 81A is multiplied by the correction coefficient for correcting the inclination of the sensitivity characteristic of the sensor stored in the ROM 84A in the multiplier 83A. Here, the offset correction amount is addition data that is uniform by detecting the lowest output difference for each A / D output pixel according to a predetermined incident light amount, and the tilt correction data is for each A / D depending on another predetermined incident light amount. It suffices to detect the highest output difference of the outputs and use the multiplied data so as to be uniform.

These correction processes are performed by the sensor (CC
Explaining with reference to the sensitivity characteristic of D), the range in which the linearity of the A / D converter 6A is secured is CC.
When the D output voltage level Dmin is changed to Dmax, the correction by the adder 81A is a process of adjusting the input data to the Dmin level, and the correction by the multiplier 83A is by adjusting the slope of the straight line of the sensitivity characteristic to obtain the maximum level Dmax. Is the process of adjusting to.

The 7-bit data from the A / D converter 6B is offset-corrected by the adder 81B, the multiplier 83B and the ROMs 82B and 84B, as described above. 7 from the multipliers 83A and 83B corrected in this way
The bit data is combined by the adder 85 as described with reference to FIG. 3, and output as 14-bit data.

By the way, since the image data captured by the CCDs 1A and 1B are separate sensor outputs, the maximum level of the CCD 1A and the minimum level of the CCD 1B do not match, as shown in FIG. If you continue, a step will occur at the seam. Eliminate this step, both C
In order to make the CD output a continuous straight line, the offset correction value generated by the signal processing unit 8 shown in FIG. 1 is supplied to the offset addition unit 5A as an analog offset voltage signal via the D / A converter 9. .

More specifically, referring to FIG.
The output voltage levels of the low-sensitivity side sensor CCD 1B and the high-sensitivity side sensor CCD 1A of the combined processed data deviate at the boundary (joint) between them. Therefore, first, the output level at the incident maximum illuminance of the CCD 1B (highlight peak of the document) is adjusted and fixed to the maximum output value Dmax as the device, and then the characteristic of the CCD 1A is offset to continuously set the boundary level. Let

For example, using a chart having a gradation in which the shade changes continuously, a portion corresponding to the boundary portion is searched and marked with the incident light quantity at which the output of the CCD 1B becomes "0000001". C at that part
It is assumed that the output of CD1A is "1111100". Here, "1111111" to "111110"
"00011" is subtracted by subtracting "0" to "000000"
"0000100" to which "1" is added is calculated as the offset value. The offset value "00001" thus obtained
00 ”is supplied to the D / A converter 9 as an offset correction value, and then as an analog voltage, the offset addition unit 5
When supplied to A and added to the output data of the CCD 1A, the two characteristic curves of FIG. 4 are continuously connected at the joint, and the gradation step is corrected.

The offset correction value is generated by the offset correction amount calculation block 300 as shown in FIG.
The offset correction value stored in the ROM 86 and read from the ROM 86 is supplied to the D / A converter 9.

Offset correction amount calculation circuit block 300
In comparison, the comparison data “00000
01 ″ is compared with the output data from the multiplier 83B in the data comparison unit 302, and when they match, the coincidence output is supplied to the latch unit 303 as a latch pulse. The latch unit 303 responds to the latch pulse. The output data from the multiplier 83A is latched.

The data comparison unit 304 compares the comparison data “1111111” stored in the memory 305 with the latch output data from the latch unit 303, and a value obtained by adding “0000001” to the difference data between the two data. Are stored in the register 306. . The register data of the book 306 is separately stored in the ROM 86.

Here, once the offset correction amount calculation circuit block 300 stores the obtained data in the ROM 86, it can be removed afterwards, and may be an external unit or a jig. Obviously, it may be included. It is also possible to adjust the offset voltage so that the register content becomes "0000000" without using a ROM or the like.

As described above in detail, in the above-described embodiment, an image is captured while moving a plurality of one-dimensional sensors (line sensors) having different sensitivities relative to the subject in the direction orthogonal to the sensor row. An image signal having a wider dynamic range than that of a single sensor is obtained by synthesizing digital data in which the time phases of signal outputs for the same image position of output are matched.

Further, a plurality of sensors having different sensitivities are used, and the sensor sensitivity ratio is determined so that the low sensitivity non-linear (non-linear) region of the single sensor is compensated by the linear (linear) region of the other sensor. Further, taking the linear region and the non-linear region (or S / N) into consideration, the sensor sensitivity ratio is set to 1: 2 ⁿ (2 ^{7 in the} above embodiment), and after converting each sensor output into n-bit data, By synthesizing by bit shifting, the final output is obtained without performing complicated processing operations. Furthermore, when correcting the gradation step difference of each sensor output data, in order to maintain the linear signal peak signal level of the sensor light output versus the incident light amount of the lowest sensitivity among the plurality of sensors, the sensor output data of the high sensitivity side The offset level is being increased or decreased. In this way, the lowest sensitivity side is fixed or the highest sensitivity side is fixed, and the offset level of the sensor output data is sequentially adjusted based on that.

Further, when stepwise correction of the data gradation at the data joining portion, attention is paid to the overlapped portion (joint) of the sensor output data which are mutually interpolated, and detection and correction are carried out. Preserve the linearity of the data. At this time, the sensor output data for extracting the portion of the image in which only the least significant bit of the data corresponding to the relatively high level is output as "1" data and interpolating the relatively low level in the same portion is each bit. The offset of the A / D input signal or the reference voltage of the A / D conversion that has already been adjusted to the input / output gain that is compatible with the system so that all values are "1" and match the value obtained by adding "1". By shifting, the gradation is corrected with high accuracy.

According to the above-described embodiment, since an image pickup output having a high dynamic range can be obtained and at the same time an arithmetic processing can be performed while inputting an image by using a plurality of sensors, the image data can be output substantially within the input time. Output is possible. Further, by optimizing the bit processing after A / D conversion, multi-tone output data can be generated by an A / D conversion element with a small data tone. In the above-described embodiment, since 14-bit effective data can be obtained especially in a dark portion which is a problem, a dynamic range of 84 db can be realized, and an image with a sufficiently high dynamic range can be input as a scanner for printing plate making.

The number of sensors is arbitrary, and the greater the number of sensors, the more remarkable the effect. Further, in the above description, the line sensor is used as the sensor, but an optically same position is effectively used as an input having different sensitivity, and each sensor output is the time of photoelectric conversion output for the same image position. The same effect can be obtained by managing the timing so that the phases match.

The present invention can be applied not only to the monochrome plate as described above, but also to a color plate. FIG. 7 (A)
6B and 6B are configuration diagrams when applied to a color plate using a plurality of line sensors as in the embodiment for each color channel. In FIG. 1A, light from the light source 100 passing through the document 101 to be scanned and moved passes through the lens 102 and the diaphragm 103 and is incident on the dichroic prism 104 that produces the optical path shown in the drawing, and the light beams are appropriately positioned. An image is formed on the R (red) sensor, the G (green) sensor, and the B (blue) sensor that have the color filters arranged in.

In FIG. 3B, instead of the dichroic prism 104, a total reflection mirror 105 and half mirrors 106 and 107 are used to disperse the incident light and form an image on the R sensor, G sensor, and B sensor. To do.

FIG. 8 shows three CCDs 1A, 1B and 1C.
FIG. 10 is a diagram for explaining an application example of the present invention in the case of using. The CCDs 1A to 1C have an ND filter attached to each single block and have a sensitivity of, for example, 0 dB or -36.
It is set to dB and -72 dB, and 3 CCD 1A
The block of 1C is moved as a whole and the scan operation is performed. R, G, and B color filters are attached to each CCD, and R, G, and B image signals are output, and the R system signal processing unit 111 and the G system signal processing having the configurations shown in FIGS. It is supplied to the unit 112 and the B system signal processing unit 113.

Instead of mounting color filters for R, G, and B for each CCD, a disk is divided into three fan-shaped areas, and a rotary color filter having R, G, and B color filters in each divided area is prepared. It is also possible to rotate this filter so that line-sequential image signals that have passed through the R, G, and B color filters are sequentially incident on a plurality of CCDs as in the embodiment.

FIG. 9 is a block diagram of a signal processing system up to image display of 14-bit image data obtained in the embodiment shown in FIG. The 14-bit image data has a high-frequency component emphasized by the high-frequency emphasis unit 21 in order to improve high-frequency reproducibility, and is stored in the field memory 22 and then an image processing station for generating a halftone dot output for platemaking. 23. The high-frequency-emphasized image data is also subjected to gamma correction by the display gamma processing unit 24,
It is stored in the display memory 25. Image data is read from the display memory 25 at a speed compatible with the display system,
The sync signals are mixed by the sync signal mixing unit 26, converted into an analog signal by the D / A converter 27, and then displayed on the monitor 29 through the low pass filter 28.

FIG. 10 is a block diagram of a color processing system to which the present invention is applied. Outputs from CCDs 1R, 1G, and 1B in which R, G, and B color filters are attached to three line sensor blocks each having a predetermined sensitivity difference are signals for performing signal processing as shown in FIGS. 1 and 2, respectively. The 14-bit image data obtained by the signal processing in the processing units 31R, 31G, and 31B is subjected to white balance adjustment in the white balance adjustment units 32R, 32G, and 32B, and then the color correction processing unit 33 performs a filter operation. A process for correcting the difference in the spectral characteristics and the like is performed.

The color-corrected R, G, and B image data are subjected to high-frequency emphasis processing by the high-frequency emphasis processing section 34. The high-frequency emphasized R, G, B image data is transferred to the image processing station 36 via the field memory 35. The R, G, and B image data are gamma-corrected by the display gamma processing unit 37 and stored in the display memory 38. The image data read out from the display memory 38 at a speed suitable for the display system is mixed with a synchronization signal by a synchronization mixing unit 39, and is input as an analog image signal to RGB through a D / A converter 40 and a low-pass filter 41. It is displayed on the monitor 42.

The exposure time can be controlled by changing the electric shutter speed of each sensor by means of differentiating the sensor sensitivity. Specifically, FIGS. 11A and 11B show the CCD.
The operation timing chart of the operations of exposure and transfer of 1A and 1B, and transfer of the photodiode charge discharge shift register is shown. As shown in FIG. 12, the CCD 1A is driven by the first timing input and the CCD 1B is driven by the second timing input.

As shown in FIG. 11A, the CCD 1A stops its exposure in the middle of the first exposure period to the second exposure period, and is mechanically moved in the middle of this period. At the end of each exposure, a transfer gate (TG) timing pulse is supplied, and the electric charge accumulated in the photodiode is discharged and reset immediately before the start of the next exposure. After the transfer gate pulse is transmitted, a pulse for performing the transfer operation of the shift register is supplied, and the output charge due to each exposure is transferred. That is, the period T from the PD charge discharge to the TG timing is set as the exposure period.

FIG. 11B shows a CCD 1A having an exposure period of 1/2 ^{7 and} a sensitivity of 1/2 ⁷ with respect to the CCD 1A.
The same operation timing for B is shown.

FIG. 13A is a block diagram of an optical system in which the loss of the amount of light incident on the sensor through the optical system is minimized as compared with the optical system shown in FIG. 7B. That is, FIG.
In the optical system shown in (B), since light is incident through the half mirror, there is a problem of loss of light quantity, but this configuration reduces such light quantity loss. In FIG. 13, the incident light has a central portion 502 which is transparent, and both side portions 501 and 503 have a total reflection mirror structure, as shown in FIG.
Then, the image is projected on each RGB sensor via a total reflection mirror 510 as shown in FIG. Further, as shown in FIG. 7C, the sensitivity of the sensors S1 and S2 arranged in parallel is -72.
An ND filter is installed in front of the sensors S1 and S2 for setting to dB and -36 dB.

Therefore, the light at the central portion of the incident light passes through the transparent portion 502 of the mirror 500, and reaches the total reflection mirror 51.
It is reflected at 0 and is imaged on the sensor S3. Light corresponding to both sides of the incident light is reflected by the total reflection mirror portions 501 and 503 of the mirror 500, passes through the ND filter, and is imaged on the sensors S1 and S2. At this time, as shown in FIG. 7B, total reflection mirrors 501 and 503 of the transparent portion 502.
Light passing near the boundary between the sensor S and the sensor S is placed at a position as shown in FIG.
1 and S2 are provided.

FIG. 14 is a diagram showing the configuration of another optical system. As shown in FIG. 14B, RGB are formed in which incident light is imaged via a total reflection mirror 611 and an ND filter (-72 dB) 612. A block 610 in which the sensor S1 is arranged, and as shown in FIG.
The block 620 in which the RGB sensor S2 for forming an image through the light is arranged, and the RGB sensor S3 in which the incident light reflected by the total reflection mirror 631 is formed as shown in FIG. The provided blocks 630 are joined in the illustrated direction to form an optical system as shown in FIG. In FIGS. 13 and 14, a black circle next to the sensor indicates the transfer start position side when the sensor is a CCD.

[0045]

As described above, according to the electronic image pickup apparatus of the present invention, a high sensitivity and high dynamic range image pickup output can be obtained even if a sensor that cannot obtain a sufficient dynamic range output by itself is used. Obtainable.

[Brief description of drawings]

FIG. 1 is a block diagram of a pre-signal processing system in an electronic image pickup apparatus according to the present invention.

FIG. 2 is a configuration diagram of a signal processing unit 8 in FIG.

FIG. 3 shows two CCDs 1A and 1 according to an embodiment of the present invention.
It is a figure for demonstrating the synthetic | combination method of the image data from B.

FIG. 4 is a diagram for explaining an example of the present invention.

FIG. 5 is a diagram for explaining an example of the present invention.

FIG. 6 is a diagram for explaining an example of the present invention.

FIG. 7 is a configuration diagram when the present invention is applied to a color plate.

FIG. 8 is a diagram for explaining an application example of the present invention when three CCDs 1A, 1B, and 1C are used.

9 is a configuration block diagram of a signal processing system up to image display of 14-bit image data obtained in the embodiment as shown in FIG.

FIG. 10 is a configuration block diagram of a color processing system to which the present invention is applied.

FIG. 11 is a diagram showing an operation timing chart of the exposure, transfer, and photodiode charge discharge shift register transfer operations of the CCDs 1A and 1B in the embodiment of the present invention.

FIG. 12 is an operation timing chart of CCDs 1A and 1B in the embodiment of the present invention.

FIG. 13 is a configuration diagram showing an optical system in which the loss of the amount of light incident on the sensor via the optical system in the embodiment of the present invention is minimized.

FIG. 14 is a configuration diagram showing another optical system in which the loss of the amount of light incident on the sensor via the optical system according to the embodiment of the present invention is minimized.

FIG. 15 is a schematic diagram showing a conventional electronic imaging device.

[Explanation of symbols]

 1A to 1C CCD (sensor) 2A, 2B Correlated double sampling section 3A, 3B Clamp section 4A, 4B Gain adjustment section 5A, 5B Offset addition section 6A, 6B A / D converter 7 Delay section 8 Signal processing section

Claims (2)

[Claims] 1. A plurality of image sensors having different sensitivity characteristics related to photoelectric conversion, and the time phases of the photoelectric conversion outputs corresponding to the same image position by the plurality of image sensors are substantially matched to each other. A dynamic range expanding means for sharing the overall photoelectric conversion characteristic by the image sensor for each characteristic region corresponding to itself, and effectively obtaining a wider dynamic range for the photoelectric conversion characteristic than that of each single image sensor. The electronic image pickup device is characterized by including: and the sensitivity of each of the plurality of image sensors is set so as to form a sequential sensitivity series in accordance with the degree of the sensitivity. The dynamic range expanding means is an upper limit or a lower limit level of the dynamic range in the comprehensive photoelectric conversion characteristic. While fixing to a predetermined upper or lower limit value for the linear region of the image sensor output located on the lowest or highest sensitivity side in the sequential sensitivity series, the sharing of each corresponding characteristic region by the plurality of image sensors is performed. When allocating, a predetermined linear area of the image sensor output corresponding to the relatively low sensitivity side or the high sensitivity side with respect to the above-mentioned sequential sensitivity series is assigned with respect to the adjacent sharing areas to be shared by the outputs of the both image sensors. In order to match the output level set as the lower or upper limit with the output level set as the predetermined upper or lower limit for the linear region of the image sensor output corresponding to the relatively high or low sensitivity side in the above-mentioned sequential sensitivity series. An offset level is added to the image sensor output corresponding to the relatively high or low sensitivity side. An electronic imaging device characterized by being configured to add. 2. The dynamic range enlarging means, when adding the offset level, is relatively low with respect to the sequential sensitivity series with respect to the adjacent sharing regions to be shared by the outputs of the image sensors. A predetermined first binary digit sequence is associated with an output level that is set to a predetermined lower limit or upper limit for a linear region of the image sensor output corresponding to the sensitivity or high sensitivity side, and relatively with respect to the sequential sensitivity sequence. The first and second binaries are associated by associating a predetermined second binary digit sequence with an output level having a predetermined upper or lower limit for a linear region of the image sensor output corresponding to the high or low sensitivity side. The difference value calculating means for obtaining the difference corresponding value as binary data by the digit series is applied, and the difference value is calculated. Electronic image pickup apparatus according to claim 1 including means for forming the operation for the offset level added based on the output of the calculation means.