JP3134944B2 - Display shooting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display photographing apparatus suitable for use in, for example, measuring the luminance of a television receiver.

[0002]

2. Description of the Related Art The vertical scanning frequency of a television receiver for consumers is 60 Hz (NTSC system) or 50 Hz (PAL system). Therefore, the vertical scanning frequency of the raster scan type video camera corresponding to these is set to 60 Hz or 50 Hz.

By the way, in a display for a computer, the vertical scanning frequency is often set to a high region of 60 Hz or more. Such an image displayed on a computer display is referred to as NTSC
When shooting with a video camera of the PAL system or PAL system,
Since the vertical scanning frequencies are not synchronized, the image flickers and image processing becomes difficult.

The flicker will be described with reference to FIG. 3. Now, the vertical scanning frequency of a video camera is 60
Hz, and the vertical scanning frequency for the computer display is 80 Hz, the vertical scanning period of each is shown in FIG.
(A) and (b) are obtained. That is, the image of the next field is displayed on the display before the video camera captures the image for one field. Assuming that the images A to G as shown in FIG. 3C are displayed on the display corresponding to the respective fields A to G in FIG. 3B, the images captured by the video camera are shown in FIG. The result is as shown in FIG.

That is, in the first field of the video camera (FIG. 3A), after the image A of the A field of the display is captured, of the images B of the B field of the display, the first field of the first field of the video camera is displayed. The image B1 up to the end is displayed on the display following the image A. Therefore, in the first field of the video camera, the image B1 is captured after the image A.

In the second field of the video camera, since the display of the image B1 has already been completed, the remaining image B2 in the B field is captured first.
Then, the image C1 up to the end of the second field of the image C of the C field is subsequently captured.

[0007] Hereinafter, in the third to fifth fields, images are similarly captured.

As a result, the output of the video camera is shown in FIG.
As shown in (e), the output of the double-exposed portion increases, and the position of the double-exposure moves periodically and sequentially in each field. This is observed as flicker.

[0009]

When the image displayed on the display is taken by the video camera as described above, the conventional apparatus does not synchronize the vertical scanning frequency of the display and the video camera. Could cause problems.

The present invention has been made in view of such a situation, and is intended to correctly measure the luminance of a display even when the vertical scanning frequency of a display and a video camera are different. is there.

[0011]

De I spray imaging apparatus of the present invention, in order to solve the problems] includes a display for displaying an image in a predetermined horizontal and vertical scanning period, of the horizontal and vertical scanning period,
At least a vertical scanning period, the vertical scanning periphery of the display
In cycle different from the period, the vertical scanning period of the video camera
Chino, a video camera for capturing an image displayed on the display, the display and the video camera in the vertical scanning
A controller for prohibiting display of an image on the display or prohibiting image capturing by a video camera during the period of the cycle difference.

[0012]

In the display photographing apparatus having the above structure,
Of the vertical scanning period of the video camera, a period of the difference between the vertical scanning period of the display and a video camera, imaging by the display or the video camera of the image is inhibited in the display. Therefore, it is possible to correctly photograph the luminance and the like on the display.

[0013]

FIG. 1 is a block diagram showing the configuration of an embodiment of a display photographing apparatus according to the present invention. The display photographing apparatus of the present embodiment includes a display 1 for displaying an image to be photographed, a video camera 2 for photographing an image displayed on the display 1, a measuring device 3 for processing an image photographed by the video camera 2, and , This display 1
And a controller 4 for controlling the video camera 2.

The display 1 outputs and displays a video signal output from the video signal generating circuit 12 on a CRT 13. The video signal generation circuit 12 can generate a video signal in response to a synchronization signal input from the external synchronization signal input terminal 11.

The video camera 2 captures an image displayed on the display 1 in synchronization with a synchronization signal input from an external synchronization signal input terminal 21 and outputs the output to the measuring device 3. I have.

The measuring device 3 comprises a memory 31 for storing video data input from the video camera 2 and a calculating device 32 for calculating data stored in the memory 31.

On the other hand, the controller 4 is supplied with a synchronizing signal generating circuit 40 for generating a synchronizing signal to be supplied to the video camera 2, an address counter 41 for counting the horizontal synchronizing signal output from the synchronizing signal circuit 40, and an address from the address counter 41. A memory (R) that outputs data corresponding to an address
AM) 42, a CPU 43 for setting a predetermined count value in an address counter 41 and storing predetermined data in a memory 42, and a synchronizing circuit for generating a composite synchronizing signal (composite blanking signal) to be supplied to the display 1. 45, memory 42 and synchronization generation circuit 4
5 is provided with a NOR gate 44 for supplying a signal inputted from the terminal 5 to the external synchronization signal input terminal 11 of the display 1.

Next, the operation will be described with reference to the timing chart of FIG. The horizontal and vertical blanking pulses output from the synchronization generation circuit 45 are supplied to the NOR gate 44.
Is input to the video signal generating circuit 12 of the display 1 via the. The video signal generation circuit 12 generates a predetermined video signal in synchronization with the horizontal and vertical blanking pulses and outputs the generated video signal to the CRT 13. As a result, a predetermined image is displayed on the CRT 13.

On the other hand, the horizontal and vertical synchronizing signals output from the synchronizing circuit 40 are supplied to the video camera 2, and the video camera 2 captures an image displayed on the CRT 13 in synchronization with the synchronizing signal. The image taken by the video camera 2 is supplied to the measuring device 3 and stored in the memory 31 thereof. The arithmetic unit 32 processes the data stored in the memory 31 and measures the characteristics of the CRT 13.

On the other hand, the CPU 43 stores in the memory 42 data corresponding to the difference between the vertical scanning frequency supplied to the video camera 2 by the synchronization generation circuit 40 and the vertical scanning frequency supplied to the display 1 by the synchronization generation circuit 45. That is,
In the memory 42, as shown in FIG. 2C, the vertical scanning cycle of the video camera 2 (FIG. 2A) and the vertical scanning cycle of the display 1 (FIG. 2B) are started simultaneously. During the period in which the vertical scanning cycle of the display 1 continues, logic H is stored, and during the period from the end of the vertical scanning cycle of the display 1 to the end of the vertical scanning cycle of the video camera 2, data of logic L is stored. ing.

The address counter 41 includes a synchronization generation circuit 40
It counts the horizontal synchronization signal input from it and outputs an address corresponding to the count value to the memory 42. The count value of the address counter 41 is reset each time a vertical synchronization signal is input from the synchronization generation circuit 40. As a result, as shown in FIG. 2C, the memory 42 outputs a signal that becomes logic H during a vertical scanning cycle of the display 1 and a logic L during a period corresponding to the difference between the vertical scanning cycles of the display 1 and the video camera 2. , To the NOR gate 44.

The output of the NOR gate 44 is
Is input as a blanking signal to the video signal generating circuit 12 via the external synchronizing signal input terminal 11. Therefore, the video signal generation circuit 12 does not display an image on the CRT 13 when a logical L signal is input from the memory 42. The image displayed on the CRT 13 is shown in FIG.
As shown in FIG.

That is, in the A field to the G field shown in FIG. 2B, for example, in the A field, a signal for prohibiting double exposure (FIG. 2C) is not generated from the memory 42 during that time. Therefore, the image A corresponding to the A field is displayed on the CRT 13 as it is.

On the other hand, in the B field, a double exposure prohibition signal (FIG. 2C) is generated in the first section. B1 corresponding to CRT1
3 is not displayed. Then, the image B2 in the remaining section is displayed on the CRT 13.

Similarly, in FIG. 2C, the image during the period indicated by the logic L is not displayed on the CRT 13 (FIG. 2D).

As a result, the image actually picked up by the video camera 2 is as shown in FIG. For example, in the first field, the image A is captured as it is. However, the image B1 is not captured because it is not displayed on the CRT 13. Next, in the second field, the image B2 in the B field is captured first, and then, of the images in the C field, the image C1 in the period until the double exposure inhibition signal is generated is captured.

In the same manner, the range of the image actually picked up by the video camera 2 is substantially only the image of the display 1 for one field period. Therefore,
The output of the video camera 2 is, as shown in FIG.
It is constant in each of the fields from the field to the fifth field. As a result, it is possible to prevent, for example, erroneous measurement of luminance in the measuring device 3.

In the above description, the display 1 is controlled by the double exposure prohibition signal. However, the video camera 2 may be controlled.

[0029]

As described above, according to the display photographing apparatus of the present invention, of the vertical scanning cycle of the video camera, the period of the difference between the vertical scanning cycle of the display and the video camera.
Since the display of the image on the display is prohibited or the imaging by the video camera is prohibited, the characteristics of the display can be correctly measured using the output of the video camera.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a display photographing apparatus according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a timing chart for explaining a problem in a conventional display photographing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display 2 Video camera 3 Measuring device 4 Controller 12 Video signal generation circuit 13 CRT 40 Synchronization generation circuit 41 Address counter 42 Memory 43 CPU 44 NOR gate 45 Synchronization generation circuit

Claims (1)

(57) [Claims] 1. A display for displaying an image in a predetermined horizontal and vertical scanning period, of the horizontal and vertical scanning period, at least a vertical scanning periphery
Period is a periodic <br/> different from the vertical scanning period of the display, a video camera that captures an image displayed on the display, of the vertical scanning period of said video camera, said display and the video camera display imaging device during the difference in the vertical scanning period, or to prohibit the display of the image in the display, or, characterized in that it comprises a controller for prohibiting the image pickup by the video camera.