JP3134949B2 - 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 the video camera is 60H.
z, vertical scanning frequency for computer display is 8
Assuming 0 Hz, each vertical scanning cycle is as shown in FIG.
And (b). In other words, before the video camera captures an image for one field,
The image of the next field will be displayed on the display. Assuming that 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 image captured by the video camera is shown in FIG. 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.

When the image displayed on the display is photographed by the video camera, the vertical scanning frequencies of the display and the video camera are not synchronized.
There was a risk that display measurements would be hindered.

Accordingly, the present applicant has filed Japanese Patent Application No. 3-13047.
As No. 8, it was previously proposed to prohibit the display of images on the display for a period corresponding to the difference between the vertical scanning frequency of the display and the video camera.

However, in the above proposal, display of an image on the display is prohibited for a period corresponding to the difference between the vertical scanning frequencies of the display and the video camera. Appeared, and the brightness fluctuated.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation. Even when the vertical scanning frequency of a display and that of a video camera are different from each other, the luminance of the display is not changed without changing the luminance. And so on can be measured correctly.

[0013]

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 frequency, of the horizontal and vertical scanning period, in a period longer than at least a vertical scanning period , A video camera for capturing an image displayed on the display,
Of the vertical scanning period of the video camera, the display
Period of the difference of the vertical scanning period of the vertical scanning period and a video camera
To, to clear the CCD imager of the charge of the video camera
And a controller.

[0014]

In the display photographing apparatus having the above structure,
Of the vertical scanning period of the video camera, the display
Period of difference between vertical scanning period and vertical scanning period of video camera
To, CCD imager of the charge of the video camera is cleared
You . Therefore, it is possible to correctly photograph the luminance and the like on the display.

[0015]

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 according to 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 includes a video signal generation circuit 12
The output video signal is output and displayed on the 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 by a CCD imager 22 in synchronization with a synchronization signal input from an external synchronization signal input terminal 21, and outputs the output to the measuring device 3. It has become.

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

On the other hand, the controller 4 is supplied with a synchronizing 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 circuit 40, and an input 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. 44.

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 44 are input to the video signal generation circuit 12 of the display 1. The video signal generation circuit 12 generates a predetermined video signal in synchronization with the horizontal and vertical blanking pulses and outputs the predetermined 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 synchronization signals output from the synchronization generation 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 synchronization signals. 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.

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 44. . That is, as shown in FIG. 2C, the memory 42 corresponds to the difference between the vertical scanning period of the video camera 2 (FIG. 2A) and the vertical scanning period of the display 1 (FIG. 2B). , A logic L, and other periods, data that is a logic H are stored.

The address counter 41 is a synchronous 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, immediately after the start of the vertical scanning cycle of the video camera 2, the memory 42 outputs a signal which becomes logic L for a period corresponding to the difference between the vertical scanning cycles of the display 1 and the video camera 2. Output.

The signal output from the memory 42 is supplied to the video camera 2. In the video camera 2, while the signal supplied from the memory 42 is at logic L, CC
The charge of the D imager 22 is rapidly discharged. As a result, the data captured by the CCD imager 22 is as shown in FIG.

That is, for example, in the first field of the video camera 2, when the charge dumping signal returns to logic H, the image of the A field on the display 1 becomes CC.
The image is captured by the D imager 22. When the display of the image of the B field is started after the display of the image of the A field on the display 1 is completed, the image is captured by the CCD imager 22. As a result, in the first field section of the video camera 2, the data in the state where the image of the B field is displayed above the display 1 and the image of the A field is displayed below the display 1 are video data as the data of the first field. Output from the camera 2.

When the second field of the video camera 2 starts, the charge of the CCD imager 22 is discarded again while the signal supplied from the memory 42 is at logic L. Then, after the signal supplied from the memory 42 returns to the logic H, the image of the B field on the display 1 is captured, and when the display of the B field is completed, the image of the C field following it is captured. As a result, the image of the second field of the video camera 2 has the image of the C field displayed above the display 1 and the image of the B field displayed below.

Further, in the third field of the video camera 2, an image of the D field of the display 1 is captured. In this case, the display 1 and the video camera 2
Of the video camera 2
Is the only image in the D field of the display 1.

Hereinafter, an image on the display 1 is captured by the video camera 2 in the same manner.

The data picked up by the CCD imager 22 is read out at a normal speed and becomes as shown in FIG. That is, an image having a constant luminance is obtained in each of the first to fifth fields. As a result, it is possible to prevent the measurement device 3 from erroneously measuring the luminance, for example.

[0030]

As described above, according to the display photographing apparatus of the present invention, the vertical scanning period of the display and the vertical scanning period of the video camera among the vertical scanning periods of the video camera are used.
The period of the difference phases, the CCD imager of the video camera charge
Is cleared, 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 a 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 Synchronization generation circuit

Claims (1)

(57) [Claims] 1. Predetermined horizontal and vertical scanningperiodImage with
Display and horizontal and vertical scanningperiodAt least vertical scanningWeek
PeriodIs the vertical scanning of the displayCycle longer than cycle
To change the image displayed on the displayCCD image
By managerA video camera for imaging,Of the vertical scanning cycle of the video camera, The disk
playVertical scanning periodAnd video camera vertical scanningperiodof
differenceofperiodTo, The video cameraCCD imager charge
ClearAnd a controller.
Display shooting device.