JPH07298129A - Image pickup device - Google Patents

Abstract

PURPOSE:To provide the image pickup device by which an image without effect due to flicker of a light source lighting an object is obtained. CONSTITUTION:An image of an object is formed on an image forming face 2 by a lens 1. The image forming face 2 is picked up while moving a line sensor 3 in the direction of arrow to obtain a 2-dimension image signal. The signal of each line forming the image is picked up for plural number of times with the line sensor 3 for a prescribed image pickup period and the image pickup signals for each pickup are added by an adder 10 and a delay circuit 11. The delay circuit 11 delays the signal by a time corresponding to the image pickup period. The effect of flicker of the light source is cancelled by the image pickup for plural number of times at a time interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for picking up a two-dimensional image by moving a line sensor (an image pickup element in which photoelectric conversion elements are one-dimensionally arranged) relative to a subject to perform sub-scanning. In particular, the present invention relates to removal of flicker when an image is captured using a light source having a brightness change.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram of a conventional image pickup apparatus for moving a line sensor relative to a subject and performing sub-scanning to pick up a two-dimensional image. In the figure, 1 is a lens for forming a subject image, 2 is an image forming surface on which the subject image is formed, and 3 is a line sensor arranged on the image forming surface 2 for converting the subject image into an electric signal. Output. Further, the line sensor 3 scans (sub-scans) the image plane 2 in a direction perpendicular to the main scanning direction, that is, a sub-scanning direction (direction of arrow in the drawing), so that a two-dimensional image can be captured. it can. The signal output by the main scanning when the line sensor 3 is at a predetermined position is sampled and held by the sample and hold circuit (S / H circuit) 4, and the analog-digital conversion circuit (A / D conversion circuit) 5
Is converted from an analog signal to a digital signal and temporarily stored in the memory A6. This operation is repeated while scanning the line sensor 3 in the sub-scanning direction, and a one-screen two-dimensional image is stored in the memory A6. Further, the image stored in the memory A6 is processed by the signal processing circuit 7,
It is converted into a video signal of a predetermined system and output 9. The output signal 9 is supplied to a monitor or recorded on a desired recording medium by a recording device. Further, the drive circuit 8 generates a drive pulse for driving the line sensor 3, the S / H circuit 4, the A / D conversion circuit 5, the memory A · 6, and the signal processing circuit 7 and for causing the line sensor 3 to perform sub scanning. It is a circuit to do.

[0003]

However, when an image of a subject is picked up by a light source with flicker such as a fluorescent lamp in the image pickup apparatus as in the above-mentioned conventional example, the light source of the light source is changed during the sub-scan of the line sensor. Since the brightness changes at a predetermined cycle, there is a problem that an image having a brightness level changed at a predetermined cycle is obtained regardless of the subject image.

The present invention has been made to solve such a problem, and an object thereof is to provide an image pickup apparatus capable of obtaining an image which is not influenced by flicker of a light source for illuminating a subject. is there.

[0005]

In order to achieve the above-mentioned object, in the present invention, the image pickup device is constructed as in the following (1) to (5).

(1) An image pickup apparatus for picking up a two-dimensional image by moving a line sensor relative to a subject, and adding signals obtained by picking up a plurality of times at a required image pickup cycle by the line sensor to obtain 1 An image pickup apparatus comprising a signal processing unit for converting signals for lines.

(2) The signal processing means is provided with a delay means for receiving the output of the line sensor and delaying it by a required imaging cycle, and an adding means for adding the output of the delay means and the output of the line sensor. The imaging device according to (1) above.

(3) The image pickup device according to (1), wherein the signal processing means includes storage means for storing the output of the line sensor, and addition means for adding the output of the storage means and the output of the line sensor. apparatus.

(4) The flicker detecting means for detecting the flicker of a light source for illuminating a subject is provided, and the image is picked up at a timing synchronized with the flicker detected by the flicker detecting means. Imaging device.

(5) An image pickup apparatus for picking up a two-dimensional image by moving a line sensor relative to an object, comprising flicker detection means for detecting flicker of a light source for illuminating the object. An image pickup device for picking up an image of each line at the timing of the same phase of flicker detected by the detection means.

[0011]

In the configurations (1) to (4) described above, signals for a plurality of lines are generated by adding signals captured by the line sensor a plurality of times at a required imaging cycle. The signal forms an image signal.

In the configuration of (5), each line is imaged at the timing of the same phase of the flicker, and the image signal is formed by the image output of a plurality of lines thus obtained.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples.

(First Embodiment) FIG. 1 is a block diagram of an "imaging device" according to the first embodiment. In FIG. 1, the same symbols as in FIG. 12 indicate the same components. Reference numeral 1 is a lens for forming a subject image, 2 is an image forming surface on which the subject image is formed, 3 is a line sensor arranged to scan the image forming surface 2, and 11 is a line sensor at a predetermined position. 3 is a delay circuit (DL circuit) that delays the same subject a plurality of times only by the imaging cycle, 10 is an adder that adds the output of the line sensor 3 and the output of the delay circuit 11, and 4 is a sample hold circuit ( S / H circuit), 5 is analog-
A digital conversion circuit (A / D conversion circuit), 6 is a memory A that stores a two-dimensional image for one screen, 7 is a signal processing circuit, and 9
Is an output converted into a video signal of a predetermined system. 8
Is a drive circuit for driving the line sensor 3, the S / H circuit 4, the A / D conversion circuit 5, the memory A · 6, and the signal processing circuit 7, and for generating a drive pulse for sub-scanning the line sensor 3. . Reference numeral 12 is a flicker detection circuit for detecting flicker of the light source, and 13 is a mode switching control circuit for switching the image pickup mode when the flicker of the light source is detected by the flicker detection circuit 12.

FIG. 2 shows the timing when the line sensor 3 at a predetermined position picks up an image of the same subject three times by the image pickup apparatus of FIG. 1 (which is also incorporated in the second embodiment). Further, in this embodiment, the sub-scan of the line sensor 3 is shown as three lines. In FIG. 2, 14 is the brightness level of the light source whose brightness changes in a predetermined cycle, 15 is the timing when the line sensor 3 at the predetermined position captures the same subject three times, 16-1, 16-2 and 16-3 is the first, second and third imaging timings of the first line in the sub-scanning direction, 17-1, 17-2 and 17-3 are the first imaging lines of the second line in the sub-scanning direction, respectively.
Second and third imaging timing, 18-1, 18
-2 and 18-3 are first, second and third imaging timings of the third line in the sub-scanning direction, respectively.
Is an imaging cycle when the line sensor 3 at a predetermined position images the same subject three times, and corresponds to the delay time of the delay circuit 11.

Next, the operation of this embodiment when the flicker is detected by the flicker detection circuit 12 and the mode switching control circuit 13 switches to the flicker removal mode will be described with reference to FIGS. 1 and 2. First, at the time of the first imaging 16-1 of the first line, the signal output from the line sensor 3 is passed by the adder 10 without adding anything,
Input to the delay circuit 11. At the time of the second imaging 16-2 of the first line, the signal output from the line sensor 3 and
The signals delayed exactly by the image pickup cycle by the delay circuit 11 are added by the adder 10 and input to the delay circuit 11 again. Also during the third imaging 16-3 of the first line, the adder 10 adds the signal output from the line sensor 3 and the signal delayed exactly by the imaging cycle by the delay circuit 11. The signal obtained by adding the first, second, and third image signals of the first line thus obtained is sample-held by the sample-hold circuit 4, and is converted from an analog signal to a digital signal by the analog-digital conversion circuit 5. It is stored in the memory A6. This operation is repeated while moving (scanning) the line sensor 3 in the sub-scanning direction, and a one-screen two-dimensional image is stored in the memory A6. Further, the image stored in the memory A6 is processed by the signal processing circuit 7, converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 2, the first (16-1, 17-1, 18-1), the second (16-2, 17-2, 18-2) and the third (1
6-3, 17-3, 18-3) is deviated from the brightness level 14 of the light source that changes in a predetermined cycle, and therefore, by adding the image signals at three different imaging times, It is possible to cancel the influence of the flicker of the light source.

With such a configuration, signals obtained by imaging the same subject a plurality of times at different times are added by using a delay circuit and an adder and treated as a signal for one line, whereby flicker of the light source is eliminated. Can offset the impact,
It is possible to solve the problem that a flicker of a fluorescent lamp, which has been a problem in the related art, gives an image in which a brightness level changes at a predetermined cycle regardless of a subject image. Further, in the present embodiment, the number of times of image pickup of each line is set to three, but the greater the number of times of image pickup, the greater the effect of canceling the influence of the flicker of the light source. Further, in the present embodiment, the sub-scan of the line sensor 3 is divided into three lines, but the sub-scan can be performed by the number of lines required for an image.

(Second Embodiment) FIG. 3 shows a second embodiment. It is a block diagram of an "imaging device." In this embodiment, the memory B.22 for storing an image of one line is used without using a delay circuit.
And the adder 10 is used to add signals captured a plurality of times. The same reference numerals as those in FIG. 1 indicate the same components, and detailed description thereof will be omitted.

Similar to the first embodiment, a case where the line sensor 3 at a predetermined position picks up the same subject three times will be described with reference to the timing chart of FIG. Also in this embodiment, the sub-scan of the line sensor 3 is shown as three lines. First, during the first imaging of the first line 16-
1, the signal output from the line sensor 3 is sample-held by the sample-hold circuit 4, the analog-digital conversion circuit 5 converts the analog signal into a digital signal, and the adder 10 passes the signal without adding anything. Memory B
Enter in 22. 16-2 at the time of the second imaging of the first line
, The signal output from the line sensor 3 and passed through the sample hold circuit 4 and the analog-digital conversion circuit 5 and the image signal stored in the memory B / 22 are added by the adder 10 and again the memory B・ Entered in 22.
Also during the third imaging 16-3 of the first line, the signal output from the line sensor 3 and passed through the sample hold circuit 4 and the analog-digital conversion circuit 5 and the memory B · 22.
The image signals stored in 1 are added by the adder 10.
The signal obtained by adding the first, second and third image signals obtained in this way is then input to the memory A6 as a signal for one line. The above operation is repeated three times while scanning the line sensor 3 in the sub-scanning direction, and a one-screen two-dimensional image is stored in the memory A6. Further, the image stored in the memory A6 is processed by the signal processing circuit 7,
It is converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 2, the first (1
6-1, 17-1, 18-1), second time (16-2, 1
7-2, 18-2) and the third time (16-3, 17-)
Since the imaging timing of (3, 18-3) deviates from the brightness level 14 of the light source that changes in a predetermined cycle, these 3
By adding image signals with different imaging times,
It is possible to cancel the influence of the flicker of the light source.

Also, in the present embodiment, the number of times of imaging of one line is three, but the effect of canceling the influence of the flicker of the light source increases as the number of times of imaging increases. Further, in the present embodiment, the sub-scan of the line sensor 3 is for three lines, but the sub-scan can be performed by the number of lines required for an image.

(Third Embodiment) FIG. 4 is a block diagram of an "imaging device" according to a third embodiment. Random access memory (or line address memory) is used as the memory C 23, and the drive circuit 8 can repeatedly read and write a predetermined line a predetermined number of times. As a result, the image signals can be added three times without using the memory B.22 as in the second embodiment, so that the memory configuration can be simplified.

According to this embodiment, the same effect as that of the second embodiment can be obtained.

(Embodiment 4) FIG. 5 is a block diagram of an "imaging device" which is Embodiment 4 (also incorporated in Embodiment 5).
5, the same reference numerals as those in FIG. 1 denote the same components, and detailed description thereof will be omitted. Two
0 is a flicker frequency detection circuit for detecting the frequency of the flicker of the light source detected by the flicker detection circuit 12,
Reference numeral 21 is a synchronization circuit for driving the drive circuit 8 in synchronization with the frequency detected by the flicker frequency detection circuit 20.

FIG. 6 shows the timing when the line sensor 3 at a predetermined position picks up an image of the same subject three times by the image pickup apparatus of the present example (also incorporated in Example 6). Further, in this embodiment, the sub-scan of the line sensor 3 is shown as three lines. In FIG. 6, 14 is the brightness level of the light source whose brightness changes in a predetermined cycle, 15 is the timing when the line sensor 3 at a predetermined position captures the same subject three times, 16-1, 16-2 and 1
6-3 is the first line of the first line in the sub-scanning direction, 2
Imaging timings of the first time and the third time, 17-1, 17-
2 and 17-3 are the first, second and third imaging timings of the second line in the sub-scanning direction, respectively.
1, 18-2 and 18-3 are the first, second and third imaging timings of the third line in the sub-scanning direction, respectively, and 19 is the time when the line sensor 3 at a predetermined position images the same subject three times. The image pickup cycle corresponds to the delay time of the delay circuit 11.

Next, the operation when the flicker is detected by the flicker detection circuit 12 and switched to the flicker removal mode by the mode switching control circuit 13 will be described with reference to FIGS. First, during the first imaging 16-1 of the first line, the synchronizing circuit 21 drives the line sensor 3 in a predetermined phase based on the frequency detected by the flicker frequency detecting circuit 20. In FIG. 6, the brightness level is set to rise. The signal output from the line sensor 3 is passed by the adder 10 without adding anything,
Input to the delay circuit 11. During the second imaging 16-2 of the first line, the line sensor 3 is driven by setting the delay time 19 of the delay circuit 11 to be delayed from the first imaging. The signal output from the line sensor 3 and the signal delayed by the imaging circuit 19 by the delay circuit 11 are added by the adder 10 and input to the delay circuit 11 again. Also during the third imaging 16-3 of the first line, the line sensor 3 is driven by setting the delay time of the delay circuit 11 to be delayed from the second imaging. The signal output from the line sensor 3 and the signal delayed by the image pickup cycle 19 by the delay circuit 11 are added by the adder 10.

The first, second and third thus obtained
The signal obtained by adding the image signals of the second time is sampled and held by the sample and hold circuit 4, and is converted from an analog signal to a digital signal by the analog-digital conversion circuit 5,
It is stored in the memory A6. This operation is performed by the line sensor 3
Repeat while scanning in the sub-scanning direction.
The three-dimensional image is stored in the memory A6.

Further, the image stored in the memory A6 is processed by the signal processing circuit 7, converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 6, the first (16-1, 17-1, 18-
1) Luminance level of the light source in which the imaging timings of the second time (16-2, 17-2, 18-2) and the third time (16-3, 17-3, 18-3) change in a predetermined cycle 14
The effect of the flicker of the light source can be canceled by adding the image signals three times in synchronism with each other and at different imaging times.

With this configuration, signals obtained by shifting the same object by a predetermined time and picked up a plurality of times are added using a delay circuit and an adder and treated as a signal for one line. The effect of flicker can be offset. In this way, it is possible to solve the problem that an image in which the brightness level is changed at a predetermined cycle is obtained irrespective of the subject image due to the influence of the flicker of the fluorescent lamp, which has been a conventional problem. Further, in this embodiment, 1
Although the number of times of image capturing per line is set to 3, the effect of canceling the influence of the flicker of the light source increases as the number of times of image capturing increases. Further, in the present embodiment, the sub-scan of the line sensor 3 is for three lines, but the sub-scan can be performed by the number of lines required for an image.

(Embodiment 5) The block configuration of this embodiment is similar to that of the fourth embodiment and is as shown in FIG.

FIG. 7 is a diagram showing the timing of this embodiment. That is, it is a timing diagram when the line sensor 3 at a predetermined position captures the same subject four times. Further, in this embodiment, the sub-scan of the line sensor 3 is shown as three lines. In FIG. 7, 14 is a brightness level of a light source whose brightness changes in a predetermined cycle, 15 is a timing when the line sensor 3 at a predetermined position images the same subject four times, 16-1, 16-2, 16-3 and 16-4 are the first line of the first line in the sub-scanning direction,
2nd, 3rd and 4th imaging timing, 17-
1, 17-2, 17-3 and 17-4 are the first, second, third and fourth lines of the second line in the sub-scanning direction, respectively.
Second imaging timing, 18-1, 18-2, 18-3
And 18-4 are 1 of the third line in the sub-scanning direction, respectively.
The second, third, fourth and fourth imaging timings,
Reference numeral 19 represents a quarter of the period of the brightness change of the light source, which corresponds to the delay time of the delay circuit 11.

Next, the operation when the flicker is detected by the flicker detection circuit 12 and the mode switching control circuit 13 switches to the flicker removal mode will be described with reference to FIGS. First, during the first imaging 16-1 of the first line, the synchronizing circuit 21 drives the line sensor 3 in a predetermined phase based on the frequency detected by the flicker frequency detecting circuit 20. In FIG. 7, the rising of the brightness level is set. The signal output from the line sensor 3 is passed through the adder 10 without any addition and is input to the delay circuit 11. At the time of the second imaging of the first line 1
In 6-2, a quarter cycle 1 from the phase at the time of the first imaging
The line sensor 3 is driven by setting the phase shift by 9. The signal output from the line sensor 3 and the signal delayed by the image pickup cycle 19 by the delay circuit 11 are added by the adder 10 and input to the delay circuit 11 again. During the third imaging of the first line, 16-3,
The line sensor 3 is driven by setting the phase to be shifted by a quarter period 19 from the phase at the time of the second imaging.
The signal output from the line sensor 3 and the signal delayed exactly by the imaging cycle 19 by the delay circuit 11 are added by the adder 1.
The value is added with 0 and input to the delay circuit 11 again. First
The line sensor 3 is driven by setting the phase 16-4 at the time of the fourth imaging of the line so as to deviate from the phase at the time of the third imaging by a quarter cycle 19. Line sensor 3
And the signal delayed by the imaging circuit 19 by the delay circuit 11 is added by the adder 10. The first, second, third and four thus obtained
The signal obtained by adding the image signals of the second time is sampled and held by the sample and hold circuit 4, and is converted from an analog signal to a digital signal by the analog-digital conversion circuit 5,
It is stored in the memory A6 as a signal for one line. This operation is repeated while scanning the line sensor 3 in the sub-scanning direction, and a one-screen two-dimensional image is stored in the memory A6. Further, the image stored in the memory A6 is processed by the signal processing circuit 7, converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 7, the first (16-1, 17-1, 18-1) of each line,
3rd time (16-2, 17-2, 18-2), 3rd time (16
-3, 17-3, 18-3), and the fourth time (16-
4, 17-4, 18-4) is synchronized with the brightness level 14 of the light source that changes in a predetermined cycle, and
Since the quarters of the cycle of the luminance change of the light source are deviated by 19 cycles, it is possible to cancel the influence of the flicker of the light source by adding these four images at different imaging times.

In the present embodiment, with respect to the integer N, "the image signals imaged N times by shifting the phase by 1 / N of the period of the brightness change of the light source are added by using the delay circuit and the adder. , Cancel the effect of flicker of the light source. ”

With this structure, signals obtained by shifting the same subject by a predetermined time and picked up a plurality of times are added using a delay circuit and an adder and treated as a signal for one line. It is possible to cancel the influence of flicker, and solve the problem that due to the influence of flicker of a fluorescent lamp, which has been a problem in the past, an image in which the brightness level changes in a predetermined cycle regardless of the subject image is obtained. be able to. Further, in the present embodiment, the number of times of imaging per line is set to four, but the greater the number of times of imaging, the greater the effect of canceling the influence of the flicker of the light source. Further, in the present embodiment, the sub-scan of the line sensor 3 is for three lines, but the sub-scan can be performed by the number of lines required for an image.

(Sixth Embodiment) FIG. 8 is a block diagram of an "imaging device" according to a sixth embodiment.

The present invention has a configuration in which signals which are imaged a plurality of times are added by using the memory B.22 for storing an image for one run and the adder 10 without using a delay circuit. The same reference numerals as those in FIG. 5 indicate the same components, and detailed description thereof will be omitted.

Similar to the fourth embodiment, a case where the line sensor 3 at a predetermined position picks up the same subject three times will be described with reference to the timing chart of FIG. Also in this embodiment, the sub-scan of the line sensor 3 is shown as three lines. First, during the first imaging of the first line 16-
First, the synchronizing circuit 21 drives the line sensor 3 in a predetermined phase based on the frequency detected by the flicker frequency detecting circuit 20. In FIG. 6, the brightness level is set to rise. The signal output from the line sensor 3 is sampled and held by the sample and hold circuit 4,
The analog-digital conversion circuit 5 converts the analog signal into a digital signal, the adder 10 passes the signal without adding anything, and inputs it to the memory B · 22. During the second imaging 16-2 of the first line, the imaging cycle 19 is longer than that during the first imaging.
The line sensor 3 is driven so that the line sensor 3 is delayed. The signal output from the line sensor 3 and passed through the sample hold circuit 4 and the analog-digital conversion circuit 5 and the image signal stored in the memory B.22 are added by the adder 10, and again the memory B.22. Entered in. Even when the third line is imaged 16-3, the first line is set to be delayed by the image capture cycle 19 from the second image capture,
The line sensor 3 is driven. The signal output from the line sensor 3 and passed through the sample hold circuit 4 and the analog-digital conversion circuit 5 and the image signal stored in the memory B · 22 are added by the adder 10. The signal obtained by adding the first, second, and third image signals obtained in this way is then input to the memory A6 as a signal for one line. This operation is repeated while scanning the line sensor 3 in the sub-scanning direction, and the two-dimensional image memory A6 for one screen is stored. Further, the image stored in the memory A6 is processed by the signal processing circuit 7, converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 6, the first (16-1, 17-1,
18-1), second time (16-2, 17-2, 18-
2) Luminance level of the light source in which the third (16-3, 17-3, 18-3) and the fourth (16-4, 17-4, 18-4) imaging timing changes in a predetermined cycle 14
The effect of flicker of the light source can be canceled by adding the image signals three times in synchronism with each other and at different imaging times.

Further, in this embodiment, it is possible to take an image by using the timing shown in FIG.

In that case, with respect to the integer N, "the light source is added by using a memory and an adder by adding the image signals imaged N times by shifting the phase by one Nth of the cycle of the luminance change of the light source. Offset the effects of flicker of. "

With such a configuration, the same object is shifted by a predetermined time and a plurality of signals captured are added using a memory and an adder and treated as a signal for one line. The effect of flicker of a fluorescent lamp, which has been a problem in the past, can be solved to solve the problem that an image in which the brightness level changes at a predetermined cycle regardless of the subject image can be obtained. You can Further, in the present embodiment, the number of times of image capturing is set to 3 or 4, but the larger the number of times of image capturing, the greater the effect of canceling the influence of the flicker of the light source. Further, in the present embodiment, the sub-scan of the line sensor 3 is for three lines, but the sub-scan can be performed by the number of lines required for an image.

(Seventh Embodiment) FIG. 9 is a block diagram of the seventh embodiment. In this embodiment, the structures of the memory and the adder are as shown. As the memory C 23, a run radam access memory (or line address memory) is used, and the drive circuit 8 can repeatedly read and write a predetermined line a predetermined number of times. This allows the memory B
Since the image signals can be added three times without using 22, the memory configuration can be simplified.

Also in this embodiment, the same effect as that of the sixth embodiment can be obtained.

(Embodiment 8) FIG. 10 is a block diagram of an "imaging device" according to an eighth embodiment. 10, components having the same reference numerals as those in FIG. 5 have the same components, and detailed description thereof will be omitted. Reference numeral 20 is a flicker frequency detection circuit for detecting the flicker frequency of the light source detected by the flicker detection circuit 12, and 21 is a synchronization for driving the drive circuit 8 in synchronization with the frequency detected by the flicker frequency detection circuit 20. Circuit.

FIG. 11 shows the timing when the line sensor 3 at a predetermined position picks up an image of a subject by the image pickup apparatus shown in FIG. Further, in this embodiment, the line sensor 3
The sub-scan of is shown as three lines. In FIG. 11, 14 is the brightness level of the light source whose brightness changes at a predetermined cycle, 15 is the timing when the line sensor 3 at a predetermined position captures an image of the subject, and 16, 17 and 18 are respectively the sub-scanning direction numbers. It is the imaging timing of the 1st line, the 2nd line, and the 3rd line.

Next, the operation when the flicker is detected by the flicker detection circuit 12 and switched to the flicker removal mode by the mode switching control circuit 13 will be described with reference to FIGS. First, at the time of imaging 16 of the first line, the synchronizing circuit 21 drives the line sensor 3 in a predetermined phase based on the frequency detected by the flicker frequency detecting circuit 20. In FIG. 11, since it is set approximately half a cycle after the rise of the brightness level, in the case of a light source such as a fluorescent lamp in which the brightness changes continuously, it is possible to take an image at the peak of the brightness level. . The signal output from the line sensor 3 is sampled and held by the sample and hold circuit 4, and is converted from an analog signal to a digital signal by the analog-digital conversion circuit 5,
It is stored in the memory A6. The same operation is repeated for the second line and the third line while scanning the line sensor 3 in the sub-scanning direction, and a two-dimensional image for one screen is stored in the memory A6. Further, the image stored in the memory A6 is processed by the signal processing circuit 7, converted into a video signal of a predetermined system and output 9. At this time, as can be seen from FIG. 11, the imaging timings of the first line 16, the second line 17, and the third line 18 are synchronized with the brightness level 14 of the light source that changes in a predetermined cycle, and the peak of the brightness level 14 is reached. Since the image can be captured with, the influence of the flicker of the light source can be canceled.

In this embodiment, a light source such as a fluorescent lamp that continuously changes in brightness is assumed, but even in the case of a light source which emits light in a pulsed manner, the image pickup timing 16, 17, 1 is used.
By changing the phase so as to emit light during 8 and synchronizing, it is possible to cancel the influence of flicker of the light source.

With such a structure, the influence of the flicker of the light source can be eliminated, and due to the influence of the flicker of the fluorescent lamp, which has been a problem in the related art, the luminance level is kept at a predetermined cycle regardless of the subject image. It is possible to solve the problem that an image in which is changed is obtained. Further, in the present embodiment, the sub-scan of the line sensor 3 is for three lines, but the sub-scan can be performed by the number of lines required for an image.

(Modification) In each of the above embodiments, the line sensor is moved to perform the sub-scan, but the present invention is not limited to this, and the subject is moved to perform the sub-scan. Can be implemented in the form.

Further, in each of the embodiments, the mode is switched at the time of flicker detection, and the image pickup signals of a plurality of times are added to generate a signal for one line. However, the present invention is not limited to this. It is also possible to carry out by adding the image pickup signals a plurality of times all the time regardless of whether or not to generate a signal for one line.

In each of the embodiments, the subject is described as being illuminated by the light source. However, the present invention is not limited to this. The same applies to the case where the subject itself includes a light source. You can Therefore, when the subject itself includes a light source, the term "light source for illuminating the subject" in the claims and the like is also used to mean the light source included in the subject.

[0050]

As described above, according to the present invention,
In an image pickup apparatus that takes a two-dimensional image by moving a line sensor relative to a subject and performing sub-scanning, a signal obtained by photographing the same subject a plurality of times at different times is added to a delay circuit and an adder or a memory. The effect of the flicker of the light source can be canceled by adding the signal using a filter and treating it as a signal for one line, or by capturing in synchronization with the brightness level of the light source that changes in a predetermined cycle. It is possible to solve the problem that due to the flicker of the fluorescent lamp, an image in which the brightness level is changed at a predetermined cycle is obtained regardless of the subject image.

Further, according to the configuration of the present invention, since the control corresponding to the frequency of the flicker of the light source is performed, the effect of the flicker can be canceled regardless of the frequency of the flicker.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment.

FIG. 2 is a timing chart of the first and second embodiments.

FIG. 3 is a block diagram of a second embodiment.

FIG. 4 is a block diagram of a third embodiment.

FIG. 5 is a block diagram of examples 4 and 5.

FIG. 6 is a timing chart of the fourth and sixth embodiments.

FIG. 7 is a timing chart of the fifth embodiment.

FIG. 8 is a block diagram of a sixth embodiment.

FIG. 9 is a block diagram of a seventh embodiment.

FIG. 10 is a block diagram of an eighth embodiment.

FIG. 11 is a timing chart of the eighth embodiment.

FIG. 12 is a block diagram of a conventional example.

[Explanation of symbols]

 6 memory A 10 adder 11 delay circuit

Claims (5)

[Claims] 1. An image pickup apparatus for picking up a two-dimensional image by moving a line sensor relative to an object, wherein signals obtained by the line sensor are picked up a plurality of times at a required image pickup cycle are added to obtain one line. An image pickup apparatus comprising a signal processing unit for converting a minute signal. 2. The signal processing means comprises a delay means for receiving the output of the line sensor and delaying it by a required imaging cycle, and an adding means for adding the output of the delay means and the output of the line sensor. The imaging device according to claim 1, wherein 3. The signal processing means comprises a storage means for storing the output of the line sensor, and an addition means for adding the output of the storage means and the output of the line sensor. The imaging device described. 4. A flicker detecting means for detecting flicker of a light source for illuminating an object, and images are taken at a timing synchronized with the flicker detected by the flicker detecting means. The image pickup device according to claim 1. 5. An image pickup apparatus for picking up a two-dimensional image by moving a line sensor relative to an object, comprising flicker detection means for detecting flicker of a light source for illuminating the object. An image pickup apparatus, wherein each line is imaged at the timing of the same phase of the flicker detected by the means.