JP3857438B2 - Color television camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color television camera having a white balance correction function, and more particularly to a color television camera suitable for imaging a limited subject.
[0002]
[Prior art]
Color video signals obtained by imaging with a color television camera are usually extracted as three independent video signals of a red (R) component, a green (G) component, and a blue (B) component. However, at this time, the levels of these three types of video signals must be matched so that when a white subject is imaged, they have a predetermined level relationship with each other.
[0003]
This level adjustment between RGB signals necessary for white reproduction is called white balance correction. As this white balance correction method, a video signal obtained by selecting a white subject and shooting it is used. A method of using and adjusting the level for each color signal is conventionally known.
For this reason, in the prior art, a white subject is imprinted on the entire imaging surface of a television camera, and the white balance is adjusted using a video signal obtained by imaging in this state.
[0004]
[Problems to be solved by the invention]
The prior art described above does not take into consideration that it is necessary to select a dedicated subject for white balance correction, and there is a problem that white balance adjustment at an appropriate timing is difficult.
[0005]
This is necessary because the white balance state of color video signals obtained by imaging with a color television camera tends to collapse due to changes in the imaging environment, such as changes in the color temperature of external light, and secular changes that appear in the imaging characteristics of the camera. It is desirable that it can be easily readjusted at any time depending on the situation.
[0006]
Therefore, in the prior art, when white balance correction is performed, a subject that is different from the original imaging subject and that is used only for white balance correction must be copied. Therefore, each time correction is performed, the original imaging operation is interrupted. Therefore, it is difficult to always achieve white balance at an appropriate timing.
[0007]
In addition, in the conventional technology, it is necessary to shoot a white subject on the entire imaging surface of the camera, but depending on the installation location and installation conditions of the camera, an appropriate subject may not be obtained. It was difficult to achieve white balance at the timing.
[0008]
In particular, it is extremely difficult to cope with white balance correction with the conventional technique when shooting a subject moving under a specific background with a fixed field of view of the camera, such as for determining arrival order in various competitions. Met.
An object of the present invention is to provide a color television camera that can reliably correct white balance only by providing a white subject in a part of an imaging field of view.
[0009]
[Means for Solving the Problems]
  The object is to provide an image for one screen captured by the linear sensor in a color television camera for determining arrival order using a linear sensor, with a white body provided at the end of the goal line to be imaged by the linear sensor. The white balance is automatically corrected by the signal of the white body portion in the signal,When a subject passes the goal line, a control signal is generated, and the control signalThis is accomplished by temporarily prohibiting the white balance correction.
[0010]
  At this time, the white balance correction may be executed when a predetermined operation is given.Yes.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a color television camera according to the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 shows an embodiment in which the present invention is applied to a color television camera for an arrival order determination apparatus using a linear sensor (one-dimensional image sensor) as an image conversion element, a so-called color linear sensor camera. In the figure, 1 represents a color linear sensor camera.
[0012]
Here, the linear sensor camera is used for determining the arrival order in a competition in which a plurality of runners compete for speed at the same time, for example, athletics, for example, a player near the goal line of the stadium The color linear sensor camera 1 according to this embodiment captures the optical image of the subject A into the color linear sensor camera 1 through the lens 2 as shown in the drawing, and the color temperature. The light passes through the conversion filter and enters the color separation prism 3.
[0013]
The color separation prism 3 constitutes a spectroscopic optical system, and incident light is branched into three optical paths for RGB color components and further transmitted through a trimming filter for each RGB color. The light component having spectral characteristics is incident on three linear sensors, that is, the G linear sensor 4-1, the R linear sensor 4-2, and the B linear sensor 4-3. The image is formed on the photoelectric conversion unit.
[0014]
The optical images input to the linear sensors 4-1, 4-2, and 4-3 in this way are converted into video signals composed of pixel data for one line for each RGB color component, and are preamplified. Are supplied to the process circuit 5-1 (for G), 5-2 (for R), and 3-3 (for B).
Therefore, in the case of a television camera using such a linear sensor, a video signal for one line becomes a video signal for one screen.
[0015]
At this time, the linear sensors 4-1, 4-2, 4-3 are driven by the scan signal 17 and the scan clock 18 supplied from the drive circuit 10, and read out the video signal.
[0016]
The video signals 16-1, 16-2, 16-3 output from the process circuits 5-1, 5-2, 5-3 are white balance amplifiers 6-1 (for G) and 6-2 (for R). , 6-3 (for B), the white balance is obtained and input to the process circuit 9. Here, the gains of the white balance amplifiers 6-2 and 6-3 are controlled by the gain signal Rg and the gain signal Bg, respectively.
[0017]
The process circuit 9 performs processing for adding a synchronizing signal and a blanking signal to the input video signal, level adjustment processing, and the like, and outputs it as an RGB color video signal Vout with white balance. Become.
This white balance processing is called white balance correction and is usually based on the level of the G video signal 16-1 in the video signal when a white subject is imaged. This is done by matching the levels of the R video signal 16-2 and the B video signal 16-3.
[0018]
That is, when the gain of the white balance amplifier 6-1 is fixed to a predetermined value and the gains of the white balance amplifier 6-2 and the white balance amplifier 6-3 are changed, white balance correction can be performed and a white subject is imaged. The magnitude of the gain signal Rg applied to the white balance amplifier 6-2 so that the levels of the video signal 16-2 and the video signal 16-3 coincide with the level of the video signal 16-1 when White balance can be obtained by adjusting the magnitude of the gain signal Bg applied to the white balance amplifier 6-3. Details will be described later.
[0019]
As described above, the video signals 16-1, 16-2, 16-3 output from the white balance amplifiers 6-1, 6-2, 6-3 are supplied to the process circuit 9, but in this embodiment, Further, it is also supplied to the gate circuits 7-1 (G), 7-2 (R), 7-3 (B), and a predetermined portion in one line period of these video signals is extracted by the gate signal 19. Signals, that is, partial video signals 23-1 (G), 23-2 (R), and 23-3 (B) are taken out, and these partial video signals 23-1, 23-2, and 23-3 are automatically whitened. It is configured to be supplied to the balance control circuit 8.
[0020]
The auto white balance control circuit 8 uses the level of the partial video signal 23-1 as a reference level, compares the level of the partial video signal 23-2 and the level of the partial video signal 23-3, and compares the partial video signal 23-2 ( The gain signal Rg corresponding to the deviation between the level of R) and the reference level and the gain signal Bg corresponding to the deviation between the level of the partial video signal 23-3 (B) and the reference level are calculated, respectively. It keeps output in the memory and outputs.
[0021]
The auto white balance control circuit 8 is activated by the application of an auto white signal 13-7 from the white balance switch 13, and during the activation, the video signal is per line or several lines. The gain signals Rg and Bg are calculated at a predetermined frequency, such as once, and are sequentially updated, held, and output.
[0022]
The counter circuit 11 generates a gate signal 19 to be supplied to the gate circuits 7-1, 7-2, and 7-3. At this time, the position T within one line period of the gate signal 19 is a gate. The gate position setter 12-1 of the adjuster 12 is set, and the gate width t is set by the gate width setter 12-2 of the gate adjuster 12.
Here, as these gate position setting device 12-1 and gate width setting device 12-2, for example, digital switches are used.
[0023]
As shown in FIG. 2B, the counter circuit 11 is configured to generate a gate signal 19 based on a scan signal 17 and a scan clock 18 supplied from the drive circuit 10, and accordingly, the scan signal The time T from the time point 20 to the gate position (time point) 21 can be determined by setting the number of scanning clocks 18 from the rising time point 17 of the 17 by the gate position setting unit 12-1 of the gate adjuster 12. In addition, by setting the number of clocks from the gate position 21 by the gate width setting unit 12-2, the time from the time point 21 to the time point 22, that is, the gate width t can be determined.
[0024]
The white balance switch 13 functions to allow the user to arbitrarily select whether white balance correction is automatically applied (automatic) or manually corrected (manual). Therefore, four switches 13-1, 13-4, 13-5, 13-6 and two variable resistors 13-2, 13-3 are provided.
[0025]
The switch 13-1 is a switch for switching white balance correction between auto and manual by manual operation. The switch 13-1 is a switch operation type switch, and the auto manual changeover switch 13-1 is in the illustrated switching position. The gain signals Rg and Bg output from the auto white balance control circuit 8 are supplied to the white balance amplifiers 6-2 and 6-3, and the manual operation is performed at the switching position opposite to that shown in FIG. , 13-3 is supplied to the white balance amplifiers 6-2 and 6-3.
[0026]
The variable resistors 13-2 and 13-3 are an R level adjusting variable resistor and a B level adjusting variable resistor, respectively. These R level adjusting variable resistor 13-2 and B level adjusting variable resistor 13 are respectively used. -3 serves to generate an arbitrary voltage within a predetermined voltage range by being manually operated.
[0027]
Therefore, in the state in which the changeover switch 13-1 is switched to the manual mode, that is, in the manual mode, the white balance amplifier is operated by operating the R level adjusting variable resistor 13-2 and the B level adjusting variable resistor 13-3. The gain of 6-2 and the gain of the white balance amplifier 6-3 can be changed independently, and the white balance can be changed manually.
[0028]
The switch 13-4 is an auto white switch which is operated to an on position and an off position. While the auto white switch 13-4 is in the on position, the auto white balance control circuit 8 receives an auto white signal 13-7. It works to output.
[0029]
Therefore, if the auto white switch 13-4 is turned on, the gain signals Rg and Bg are sequentially updated by the auto white balance control circuit 8, and when the auto white switch 13-4 is turned off, the gain signals Rg and Bg are The value immediately before the switch 13-4 is turned off is maintained.
[0030]
The switch 13-5 is a one-push auto white switch, which is a push button switch or the like that is turned on only when an operating force is applied by hand. The auto white balance control circuit 8 is supplied with an auto white signal only while it is on. It works to output 13-7.
Therefore, if the one-push auto white switch 13-5 is pressed, the gain signals Rg and Bg corresponding to the white balance state of the video signal at that time can be updated.
[0031]
The switch 13-6 is an auto white balance prohibition switch, and is composed of a contact of a normally closed contact type relay or an electronic switch. It works to prohibit 7 from being input.
Therefore, when the control signal 14 is applied, the update of the gain signals Rg and Bg by the auto white balance control circuit 8 is unconditionally prohibited.
[0032]
Next, the operation of the color linear sensor camera 1 according to the embodiment of the present invention will be described focusing on the white balance correction operation.
As described above, in this color linear sensor camera 1, the gate circuits 7-1, 7-2, and 7-3 are provided, and thereby, a signal obtained by extracting a predetermined portion in one line period of the video signal, That is, the partial video signals 23-1, 23-2, 23-3 are supplied to the auto white balance control circuit 8, and the gain signals Rg, Bg are calculated.
[0033]
The gains of the R white balance amplifier 6-2 and the B white balance amplifier 6-3 are controlled by these gain signals Rg and Bg, whereby the white balance is corrected and the white balance is obtained. Therefore, even if the entire subject A is not white, as long as only the portions corresponding to the partial video signals 23-1, 23-2, 23-3 of the subject A are white, the white balance Correction is possible and white balance can be achieved.
[0034]
In addition, at this time, in this color linear sensor camera 1, as described above, the gate adjuster 12 extracts the video signal at an arbitrary time width from any position in the video signal for one line and outputs the partial video. Since the signals 23-1, 23-2, and 23-3 can be used, if there is even a slight white portion in a part of the subject A, the partial video signal 23 is generated regardless of where the white portion is. -1, 23-2, 23-3 can be easily taken out.
[0035]
That is, as shown in FIG. 2B, the operation of the gate position setting unit 12-1 and the gate width setting unit 12-2 of the gate adjuster 12 synchronizes the video signal 16 with the one line period. Thus, the counter 11 can generate a gate signal 19 having an arbitrary time width t that rises at an arbitrary time position T from an initial time point of the one line period and falls at an arbitrary time point 22, and is therefore illustrated in FIG. As described above, an arbitrary portion P in the video signal 16 for one line can be extracted.
[0036]
For this reason, first, in this embodiment, as shown in FIG. 1, the gate signal 19 is also input to the process circuit 9, whereby the display surface of the video signal monitor device (not shown) is displayed on the display screen of FIG. As shown, the gate signal 19 can be displayed together with the video signal 16.
The video signal 16 at this time may be any of the video signals 16-1, 16-2, and 16-3, but generally, the G video signal 16-1 is displayed. Just keep it.
[0037]
In this embodiment, as a preparatory work for auto white balance correction, first, the position T and width t of the gate signal 19 are set by the gate adjuster 12.
As described above, such a linear sensor camera is often used in an arrival order determination device or the like.
In this case, as shown in FIG. 2 (a), the color linear sensor camera 1 is focused on an arrival order determination line such as a goal line, and is used in a state where only that portion is imaged. Indicates that the goal line is the subject area A of the color linear sensor camera 1._L It becomes.
[0038]
Therefore, as shown in FIG._L The predetermined white body A at the end of_LW Is installed. Then, this is imaged by the color linear sensor camera 1.
At this time, subject area A_L Is generally considered to be in the same illuminance environment, the subject area A_L White body A_LW Therefore, as shown in FIG. 2B, the white body A in the video signal 16 should be maximized._LW The portion by can be easily identified as the maximum level portion P.
[0039]
Therefore, the gate position setter 12-1 of the gate adjuster 12 is operated to move the gate signal 19 left and right (time axis direction) on the monitor surface, and as shown in FIG. If the gate width t is adjusted by the gate width setting unit 12-2 in accordance with the portion P, the position T and the width t of the gate signal 19 can be easily set, and the preparation work can be completed.
[0040]
Note that the setting operation of the position T and the width t of the gate signal 19 by the gate adjuster 12 as the preparatory work is in principle performed in the subject area A._L First, white body A_LW It is only necessary to perform this operation when the relationship is changed and when these relations are changed. However, at other times, for example, if it is executed periodically, a reliable operation can always be expected.
[0041]
After completing the above preparatory work, the white body A by the color linear sensor camera 1 is used._LW Subject area A_L While the image pickup operation is being performed, the auto white balance control circuit 8 includes the white body A_LW The partial video signals 23-1, 23-2 and 23-3 are supplied to the auto white balance control circuit 8, and as a result, the auto white balance control circuit 8 is applied with the auto white signal 13-7. The gain signal Rg and the gain signal Bg necessary for automatically obtaining the white balance are calculated by feedback processing on the condition that the auto manual changeover switch 13-1 is switched to the auto side.
[0042]
The calculation operation by the feedback processing of the gain signals Rg and Bg by the auto white balance control circuit 8 at this time will be described with reference to FIG.
White body A now_LW Subject area A_L The video signals 16-1, 16-2, 16-3 obtained by imaging are shown in the figure, and the partial video signals 23-1, 23-2, 23-3 extracted by the gate signal 19 are shown in the figure. Suppose it was street.
[0043]
Here, a state in which the white balance is lost is shown, and accordingly, the partial video signal 23-2 (R) and the partial video signal 23- with respect to the level H of the reference partial video signal 23-1 (G). The level of 3 (B) is different.
Here, the case where the level difference is low is shown, but it goes without saying that the level may be high.
[0044]
Therefore, the auto white balance control circuit 8 sequentially compares the partial video signal 23-1 and the partial video signal 23-2, and changes the value of the gain signal Rg in a direction in which the difference between these levels decreases. . That is, when the level of the partial video signal 23-1 is lower than the level H, the gain signal Rg is sequentially increased. On the contrary, when the level of the partial video signal 23-1 is higher than the level H, the gain is sequentially increased. The signal Rg is decreased.
[0045]
Then, the value of the gain signal Rg when the levels match is sequentially stored in a predetermined memory. The storage of the gain signal Rg in the memory at this time is so-called data update, and each time the gain signal Rg is newly calculated, the previously stored data is rewritten and held with the new gain signal Rg. It becomes operation.
The same applies to the partial video signal 23-3. The value of the gain signal Bg when the level matches is obtained by changing the value of the gain signal Bg in the direction in which the level difference from the partial video signal 23-1 decreases. Are sequentially updated and held.
[0046]
In FIG. 3, the state when the level matching is obtained in this way is represented by partial video signals 24-1, 24-2 and 24-3, and this is a state where white balance is achieved. That is, the levels of the partial video signals 24-1, 24-2, and 24-3 are all the same and are aligned with the level H of the partial video signal 24-1.
This state is always obtained automatically as long as the auto white signal 13-7 is applied and the auto manual changeover switch 13-1 is switched to the auto side, and a constant correction operation by automatic tracking is obtained. It will be.
[0047]
Therefore, according to this embodiment, if there is a white portion in a part of the imaging field of view, the white balance can be automatically obtained only by that, so there is no need to change the subject for correction, and the original subject is imaged. In such a state, it is possible to always perform imaging with correct white balance.
As a result, according to this embodiment, it is possible to easily achieve white balance even in the case of a subject that does not have a white portion that can be used for white balance correction by simply installing a small white body in the imaging field of view. Therefore, it is possible to always obtain a video signal in an appropriate white balance state without being restricted by the subject.
[0048]
By the way, when the goal line is a white line in athletics etc., the white balance may be corrected by the white of the goal line if the linear sensor is aligned with the line, but the goal line Since the color is not necessarily white that is suitable for white balance correction, a white body A is separately provided at this time._LW It is desirable to install.
[0049]
On the other hand, the goal line is not always a white line in a bicycle race, a horse race, or the like, and a water surface enters the goal line in a boat race or the like.
However, even at this time, according to the embodiment of the present invention, the white body A_LW Therefore, white balance can be easily obtained.
Even at this time, the white body A within the imaging field of view_LW The installation position can be chosen arbitrarily and the size can be small, so there are very few restrictions on its installation, and in most cases it can be easily applied, and a high-quality with automatic white balance. A color video signal can be easily obtained.
[0050]
By the way, in the embodiment shown in FIG. 1, the white balance switching unit 13 is provided, so that the white balance correction is not limited to the above-described normal correction operation based on the automatic tracking. The manual correction operation by the operation of the devices 13-2 and 13-3 and the one-push auto white correction operation by the operation of the one-push auto white switch 13-5 can be selected.
[0051]
The normal correction operation by automatic tracking is a mode obtained by closing the auto white switch 13-4 with the auto manual changeover switch 13-1 in the illustrated auto changeover position. By automatically following changes in color temperature and illuminance, it is possible to keep a white balance.
[0052]
The manual correction operation is a mode obtained when the auto manual change-over switch 13-1 is set to a switching position opposite to that shown in the figure. At this time, the R-level adjusting variable resistor 13-2 and the B-level adjusting variable resistor are used. By operating 13-3, the white balance can be arbitrarily changed manually. Therefore, it can be used when the white balance is to be lost for some reason.
[0053]
The one-push auto white correction operation is a mode that can be obtained only when the one-push auto white switch 13-5 is pressed and turned on while the auto white switch 13-4 is open. Automatic white balance can be achieved according to the white balance state.
[0054]
  In this embodiment, the auto white balance prohibition switch is added to the white balance switch 13.13-Thus, as described above, the update of the gain signals Rg and Bg by the auto white balance control circuit 8 is unconditionally prohibited by the control signal 14 given from the outside.
  The control signal 14 at this time is a signal generated when a video signal from the color linear sensor camera 1 is recorded, and an auto white balance prohibition switch13-As described above, reference numeral 6 denotes a normally closed contact type relay contact or an electronic switch, which is turned on only when the control signal 14 is input.
[0055]
  Here, when the color linear sensor camera 1 is used as an arrival order determination device as in this embodiment, the arrival order is determined after a video signal of a subject such as a runner passing the goal line is recorded. It is like that.
  Therefore, in this embodiment, when the subject passes the goal line, the control signal 14 is generated and supplied to the auto white balance prohibiting switch 13-6 to open the switch.
[0056]
In this embodiment, when the white balance is always corrected by automatic tracking, another subject is a white body A._LW If it is reflected in the video, the white balance may be lost.
Therefore, in this embodiment, when the subject passes the goal line, the white balance state is temporarily fixed. Therefore, according to this embodiment, the present invention is applied to the arrival order determination device. Even in this case, it is possible to reliably prevent the white balance from being lost, and it is possible to accurately determine the order of arrival under a stable video signal.
[0057]
In the above embodiment, the case where the present invention is applied to a color linear sensor camera has been described. However, it goes without saying that the present invention is also applicable to a color television camera that captures an image in units of frames. .
In this case, instead of extracting the partial video signal in units of one line, the video signal may be extracted from a part having an arbitrary width at an arbitrary position in one frame as a partial video signal.
[0058]
【The invention's effect】
According to the present invention, if there is even a white portion in the imaging field of view of the color television camera, white balance can be automatically achieved.
Therefore, according to the present invention, it is possible to automatically provide a color television camera capable of automatically taking a white balance even during a normal imaging operation and capable of always capturing a high-quality color image.
[0059]
Also, even with automatic tracking white balance, there is no white balance deviation when the subject passes.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to a color linear sensor camera.
FIG. 2 is an explanatory diagram of a photographing operation according to an embodiment of the present invention.
FIG. 3 is a timing chart for explaining the operation of an embodiment of the present invention.
[Explanation of symbols]
1 Color linear sensor camera
2 Imaging lens
3 color separation prism
4-1 to 4-3 linear sensor
5-1 to 5-3 Process circuit for preamplification
6-1 to 6-3 White balance amplifier
7-1 to 7-3 Gate circuit
8 Auto white balance control circuit
9 Process circuit
10 Drive circuit
11 Counter circuit
12 Gate adjuster
12-1 Gate position setting device
12-2 Gate width setting device
13 White balance selector
13-1 Auto manual switch
13-2 Variable resistor for R level adjustment
13-3 Variable resistor for B level adjustment
13-4 Auto white switch
13-5 One push switch
13-6 Auto white balance prohibition switch

Claims (1)

In a color television camera for determining arrival order using a linear sensor,
A white body is provided at the end of the goal line to be imaged by the linear sensor,
The white balance is automatically corrected by the signal of the white body portion in the video signal for one screen imaged by the linear sensor, and
A color television camera configured to generate a control signal when a subject passes the goal line, and to temporarily prohibit the white balance correction by the control signal .

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