JPS61247173A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent the effect of flicker due to fluorescent lamp lighting by correcting automatically an image pickup time into a prescribed range narrower than the setting range after it is detected by a detection means that an object is lighted by fluorescent light. CONSTITUTION:A flicker detection circuit 17 detects a flicker component included in a signal corresponding to an R/B. When the level of the flicker component is a prescribed level or over, a detection signal 17a from the flicker detection circuit 17 goes to a high level and a switch 11 is turned off, then an output of an image pickup time setting circuit 10 is shut. Even when a special image pickup time is set by an image pickup time setting circuit 10, the pickup time is corrected forcibly to, e.g., 1/60sec in case of the fluorescent lamp lighting.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a photographic device that is compatible with various types of AAK.

[Summary of disclosure]

This specification and drawings describe an imaging device capable of capturing images under various light sources, which detects whether or not a subject is under fluorescent lamp illumination, and detects whether or not a subject is under fluorescent lamp illumination. discloses a technique that makes it possible to eliminate the adverse effects of fluorescent light by correcting the imaging time so that it falls within a predetermined range.

[Prior art]

Conventionally, in order to capture images of rapidly moving subjects with high image quality, an optical shutter was provided in front of the image sensor, and this shutter was used to shorten the exposure time of the image sensor. Are known.

In addition, there is also a device in which the actual external storage time can be shortened by discarding the pixel charge in the image sensor to an overflow drain or the like at an appropriate timing, for example, as disclosed in JP-A-52-
No. 79615, etc. [Problems to be solved by the invention] However, when imaging is performed under various conditions using the ms device designed to be able to variably control the 1cIk time, the following occurs. It has been discovered that the brightness of the screen may be abnormally bright or dark indoors.

Of course, such a problem occurs even if the image signal level is set by the aperture, shutter, and sensitivity control means before photographing.

This is because the brightness of the subject changes with a cycle of 1/2 of the applicable power supply cycle due to the fluorescent light source.
It was also confirmed that this is noticeable when the period is shorter than the period. The present invention has been made in view of the above-mentioned points, and its nine objectives are to provide an imaging device capable of reducing the influence of 71V power caused by a fluorescent button.

[Means for solving problems]

The present invention is an imaging device that can take images under various light sources, and includes imaging means such as an imaging tube and a solid-state image sensor for imaging a subject.

Further, it has an imaging time setting means for variably setting the imaging time by the imaging means by changing the exposure time, accumulation time, etc. Furthermore, a detection means for detecting that the subject is under fluorescent light illumination is provided, and based on the output of this detection means,
The imaging time setting means automatically controls the correction means for correcting the imaging time. [Operation] The imaging time setting means performs actual imaging by the imaging means, for example, by manual setting with a dial or automatic setting according to the brightness of the subject. Outputs a signal to set the time.

However, when it is determined by the detection means that the subject is illuminated by a fluorescent light, the above-mentioned imaging time is determined to be within a predetermined range narrower than the settable range based on the output of the detection means. Corrected automatically.

Therefore, even if a very short imaging time is set in advance by the imaging time setting means, it will not be affected by the effects of fluorescent lamp illumination.6 [Example] The following is a detailed description of the present invention based on an example. Do the following.

FIG. 1 is a diagram showing a first embodiment of the present invention, and is an example in which an external colorimetric sensor detects 7 lights of a light source, and when 7 lights are detected, the imaging time is set to the standard television cycle. ◎ In the figure, reference numeral 1 is an image sensor as an imaging means, and a color separation filter (not shown) is placed in front of it.The output of the image sensor is separated into colors by sample and hold circuits 2 to 4, which operate at different sampling timings. For example, Ro
Gain control amplifiers 5 and 6 are provided for the R signal and B signal channels, respectively, and the white balance controller 16, which will be described later, adjusts the white balance according to the color temperature of the subject. Control is exercised. The R, G, and B color signals subjected to white balance control are converted into Y, R-Y, and B-"I signals by the matrix encoder 7, and then R-Y and B-Y have a phase difference of 90', respectively. The signal is superimposed on the Y signal by the carrier in the balance chamber 111FI-g to form an NT80 signal as a standard television signal. 8 is a process unit that performs a series of processes like this.

Reference numeral 9 denotes an image pickup device driving circuit that performs image accumulation, scanning, charge removal, etc. in the image pickup device at a constant cycle in synchronization with a synchronization signal from a synchronization signal source shown in the cine. Reference numeral 10 denotes an imaging time setting circuit which outputs a signal corresponding to an imaging time manually set using a dial or the like as shown in the cine. Note that the setting circuit 10 also includes one that automatically sets the imaging time variably according to the brightness of the subject.

The signal indicating the imaging time with switch 1 as a correction means
1 to the drive circuit 9, and the switch 11
is OFF, the image storage time in the image sensor 1 is set to OFF, for example, the standard television field period (N
(approximately 1750 seconds for T80), and switch 11 is turned on.
If the image storage time is set, the image acquisition time setting circuit 1o
variable control according to the output. Specifically, in the image sensor, when the switch 11 is turned on, the image signal that has been accumulated up to that point is led to an overflow drain and removed during the field period.@Therefore, after this removal is completed,
This is why the round surface signal accumulated during the remaining field period becomes an effective imaging signal. Note that the switch 11 is normally turned on. 18 is a color measurement section, and 12 is a white diffuser plate that averages the subject light. It may be assumed that this averaged object light represents the light of the light source.
3. The R and B components in the subject light are detected by the 8-color sensor 14.
Detect levels of ingredients. The outputs of the R sensor and B sensor are calculated in the calculation circuit 15 to form a signal corresponding to R/'B busy.

Here, R/B has a one-to-one correspondence with the color temperature of the subject. That is, there is a correspondence relationship such that the larger ψ is, the lower the color temperature is, and the smaller Rc is, the higher the color temperature is.

Therefore, based on the R/BK corresponding signals, the controller 16 forms control signals 16a and 16b for controlling the gain of the gain control amplifier 56, respectively, and adjusts the balance of the R, G, and B channel signals to the color temperature. control accordingly.

17 is a 7-bit power detection circuit that detects the flicker component contained in the signal corresponding to R/B.
When the component is at a predetermined level or higher, the detection signal 17a from the detection circuit 17 becomes high level. When the signal 17a becomes high level, the switch 11, which is normally ON, is turned OFF, and the output ha of the imaging time setting circuit 10 is cut off.

Therefore, even if a special imaging time is set by the ms time setting circuit 1o, in the case of fluorescent lamp illumination, the imaging time is forcibly corrected to, for example, 1/60 seconds. If there is, as mentioned above, it is longer than 1/Ion second (Kanto) and 1A20 seconds (Kansai), which are 1/2 of the commercial power supply cycle, so the influence of 7 Ritzker is removed.

In addition, according to the experiment Kj, it was confirmed that when the commercial power supply cycle is 1000 seconds, the influence of flicker can be suppressed to 5% or less if the power supply is approximately 1 A for 25 seconds or more.

Next, FIG. 2 is a diagram showing a second embodiment of the present invention, in which the same reference numerals as in FIG. 1 represent the same elements.

19 is a shutter as an exposure control means for limiting the imaging time; 20 is a shutter control circuit for controlling opening/closing of the shutter 19; 21 is a changeover switch as a correction means; Setting circuit 10 also selectively routes the output of reference signal source 22.

When the switch 21 is connected to all K, the output of the imaging time setting circuit 10 is guided to the shutter control circuit 20, and nine signals are sent from the circuit 10 corresponding to the imaging time, which can be set manually using a dial (not shown) or the like. Since the output level is low, the shutter opening time is controlled according to this signal, and the imaging time is variably controlled. A reference signal corresponding to the imaging time is output, and the shutter control circuit opens the shutter 19 for 17120 seconds at a predetermined timing to correct the imaging time.
This is done by the output 17a of 7.

Immediately, switch 21 is at contact a while 17a is at low level.
It is connected to the contact 1 side while 17a is at high level.

Therefore, when the 7-picker is detected, the imaging time Ke is corrected to a predetermined imaging time regardless of the imaging time setting by the imaging time setting circuit.

As described above, the present invention also includes a device in which the imaging time is controlled by shutter control.

In addition, according to this second example, unnecessary y is required compared to the first example.
8/H with no smear as the noise component due to t is reduced.
You can get a good Eirin signal.

In addition, in the above first and second embodiments, an example is shown in which the imaging time at the time of 7 flicker detection is set to a constant value such as 1/60 second or 1/120 second. Sometimes shooting g1
The control may be such that the time is greater than a predetermined lower limit.

FIG. 3 is a diagram showing the third embodiment of the present invention.
, ta2 Figures with the same reference numbers indicate the same elements.

The sequence controller serves as a 25Fi correction means, and includes a program according to the flowchart shown in FIG. 4, for example.

A trigger circuit 24 generates a trigger signal by operating a button (not shown).

This trigger signal is input to the sequence controller 23. Reference numeral 25 denotes a gate circuit, which is opened and closed by a control signal from the sequence controller 25.

Reference numeral 26 denotes a recording device, which includes, for example, a VTR.

Note that the output of the imaging time setting circuit 10 is input to the shutter control circuit via the sequence controller 23.

Next, refer to the flowchart in Figure 4 and read the book! I! 6. Describing the operation of the embodiment 70 grams is started in step #1, and the imaging time T set in the setting circuit 10 is read into the memory in the sequence controller 23 in step #2. Next, in step #3, it is determined whether or not 17a is at a high level. If 17& is at a low level, that is, when the 7 hiter is not detected, the process proceeds to step #4, and it is determined whether or not the output of the trigger circuit 24 is at a high level. Discern. Meanwhile in step #3 17a
When it is determined that the signal is at a high level, that is, flicker has been detected, the process proceeds to step #5 and it is determined whether "s>'ro". This is the lower limit of the imaging time within which the error falls within the allowable range, and is predetermined based on the cycle of this company's 7 Ritzker and the characteristics of the imaging system. /120
It is desirable to set the time to about 1/125 seconds, and if 0Ts≧To, the adverse effects of 7Ritzkers can be ignored, so go to step #4! nothing.

On the other hand, if Ts (To, then step #6 and −11
, Ta to TolCL, and then proceed to step #4.

Step #4 waits until the output of the trigger circuit 24 reaches the high level, and when it reaches the high level, it is then determined in step #7 whether or not the vertical synchronizing signal VD has been obtained. When VD is obtained, the process proceeds to step #8, where a control signal is sent to the shutter control circuit 20 to open the shutter. Next, in step #9, the operation of a counter (not shown) in the controller 25 is started.

In step #10, the count value of the counter is changed to the time Tsi.
Determine whether C has been reached, and if it has been reached, step -8111
Proceed to C and close the shutter. Exposure time T from this K
Exposure control of s is completed.

Thereafter, in step #12, VD is detected again, and if VD is detected, the process proceeds to step #13, where the gate circuit 25 is controlled and the gate is made conductive (closed). Also, in step #14, a counter (not shown) is started, and step #1 is started.
At 5! It is determined whether To (Ik immediate period) has elapsed.

That is, when 1V has elapsed after the gate circuit 25 is made conductive, the gate circuit 25 is opened.

As a result, the image quality signal formed by exposure (by the shutter 19) is recorded in the recording device 26.
Step #17 ends 14 grams.

In this way, according to this embodiment, if the preset imaging time is within the range where the preset imaging time is influenced by the fluorescent light, the imaging time is not corrected, and if it is within the affected range, the imaging time is adjusted. Since the correction is made to a constant value, the intention of the photographer can be more accurately reflected. It is possible to capture images that reflect the

In the above embodiment, it is determined that the light source is a fluorescent light source by detecting 7 lights, but it is determined that the light source is a fluorescent light source by detecting a spectrum peculiar to a fluorescent light source. You can also do it. As described above, the present invention is not limited by the method of determining the fluorescent lamp light source.

〔Effect of the invention〕

As explained above, according to the present invention, by detecting when the subject is under fluorescent light illumination, even if the transport time is arbitrarily set, the button can be automatically set in advance to allow a relatively narrow Since it is corrected to the shooting time range, an appropriate signal level can always be obtained even when shooting with a fluorescent knife.

[Brief explanation of drawings]

FIG. 1 is a diagram of a first embodiment of the present invention, FIG. 2 is a pJ2 embodiment diagram of the present invention, FIG. 3 is a diagram of a third embodiment of the present invention, FIG. 4 is a 70-chart of the third embodiment. 1...borrowed camera element 8...Process section 10... Shooting time setting circuit 17... Flicker detection circuit 111e...Switch Return to top of this invention Collection 1■

Claims (1)

[Scope of Claims] Imaging means for capturing an optical image of a subject, imaging time setting means for variably setting the imaging time by the imaging means within a predetermined range, and detection means for detecting that the subject is under fluorescent light illumination. An imaging device comprising: a correction unit that corrects an imaging time to be within a range narrower than the predetermined range based on a detection output by the detection unit.