JPH05167958A - Picture signal forming method for liquid crystal display - Google Patents

Abstract

PURPOSE:To make pictures on a liquid crystal board easy to see and to display a picture with clear light and darkness on a liquid crystal display board by monitoring pictures in the liquid crystal display board to record pictures photographed by a CCD camera on a RAM and IC cards. CONSTITUTION:In converting video signals outputted by the CCD camera into the picture data of digital signals, a signal to be displayed on the liquid crystal display board is taken in the several frames in a video signal based on a take-in signal. Based on the sampling signal, the maximum value of the picture data in one field of a frame which is not displayed on the liquid crystal display board is detected. Based on the maximum value, the amplification rate of video signals at the A/D conversion when the take-in signal is outputted is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for converting a video signal which is an analog signal into image information of a digital signal when displaying an image on a liquid crystal display board by a video signal captured by a small CCD camera.

[0002]

2. Description of the Related Art The applicant of the present invention has a CCD camera and a liquid crystal display plate in advance, and confirms the field of view of the CCD camera with the liquid crystal display plate while using the field of view of the CCD camera as image information of a digital signal and using a random access memory. We have developed a portable recording device that can be stored in RAM (hereinafter referred to as RAM).

As shown in FIG. 4, this recording device 10 has five
A book type having a plurality of operation switches 15 around a liquid crystal display plate 41 of about inch is provided, and the field of view of a CCD camera provided on the side or the back is projected on the liquid crystal display plate 41 (hereinafter referred to as LCD). The image projected on the LCD 41 by operating is stored in the RAM as 4-bit image data determined by the brightness of 16 gradations.

As shown in FIG. 3, the portable recording device 10 stores various programs together with a main central processing unit 21 (hereinafter referred to as main CPU) and an auxiliary central processing unit 23 (hereinafter referred to as sub CPU). A read-only memory 25 (hereinafter referred to as P-ROM) and a font read-only memory 27 (hereinafter referred to as FR) in which character information is stored.
OM27), a random access memory 29 (hereinafter referred to as RAM) for temporarily storing programs and information necessary for the main CPU 21 to perform work, and an input for removing information from the outside and importing information from the outside. The output device 35 and the IC card 17 capable of writing or reading image information through the interface 19 are provided.
A video signal which is image information from the CD camera 11 is taken into the interface 13 through an operational amplifier 12 (hereinafter referred to as an operational amplifier), and a video signal which is an analog signal while taking in control signals such as a vertical synchronizing signal and a horizontal synchronizing signal. Is added to the image data as a 4-bit digital signal.
Converted by D camera interface 13 and sub CPU2
3 detects that the appropriate switch 15 is operated, and the field of view of the CCD camera 11 is displayed on the LCD 41 by the data processing of the gate array 31 and the main CPU 21, and the gate array 31 causes the main CPU 2 to operate.
1 and the CCD camera 11 and the LCD 41 control the timing of accessing the video random access memory 33 (hereinafter referred to as V-RAM) so that the image displayed on the LCD 41 is not disturbed.

A liquid crystal display panel control device 42 (hereinafter referred to as LC
The 4-bit image information sent to the D controller) is a density signal for controlling the open lighting time of each pixel in the LCD 41 by the LCD controller 42,
An image represented by gradation of gradation is displayed on the LCD 41, and while the field of view of the CCD camera 11 is monitored by the LCD 41, the information of the still image is stored in the RAM 2 by operating the switch 15.
9 and IC card 17 to record.

[0006]

When converting a video signal of a CCD camera into image information of a digital signal, 16
In order to effectively use the gradation and record high-resolution, high-quality image information, it is desirable to correct the brightness level according to the brightness of the entire field of view captured by the CCD camera. Or it was necessary to provide a level sensor separately from the CCD camera.

[0007]

According to the present invention, an image is displayed on an LCD by image data obtained by analog-digital conversion of a video signal output from a CCD camera, and
The display on the LCD is such that an image is displayed by using the image information of one frame every several frames, and the maximum value of the image data in one field in the frame in which the image is not displayed on the LCD is detected, and based on the maximum value. The analog
The conversion rate during digital conversion will be adjusted.

[0008]

[Operation] According to the present invention, when the image is displayed on the LCD based on the video signal output from the CCD camera, the number of frames is reduced to 1 in several frames.
Since one frame of image information is fetched each time and the image information is displayed on the LCD, the LC of the video signal is
The image data of the field that does not display D is generated, and the image data of the field that does not display can be processed by processes other than LCD display such as peak value detection without being restricted by data processing.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the apparatus for carrying out the method of the present invention is the recording device 10 with LCD for processing the video signal of the CCD camera 11 as a 4-bit digital signal by the CCD camera interface 13 as described above. In this recording device 10, the CCD camera 11 outputs a video signal of an analog signal as well as a control signal such as a horizontal synchronizing signal and a vertical synchronizing signal, and the video signal is appropriately amplified by an operational amplifier 12. After that, it is converted into a 4-bit digital signal by the CCD camera interface 13, converted into image data having 16 gradations, stored in the V-RAM 33 under the control of the gate array 31, and controlled by the gate array 31 and the main CPU 21. LCD 41
The image is projected on.

In processing the 4-bit image information output from the CCD camera interface 13, in this embodiment, a frequency dividing circuit is formed in the gate array 31, and the vertical synchronization output from the CCD camera interface 13 is formed. A reference signal is generated by dividing the signal into even-numbered divisions such as 1/4 division and 1/6 division, and based on this reference signal and the vertical synchronization signal, after the rising of the reference signal, first The sampling signal is output before the vertical synchronization signal of 1 and then the capture signal is output.

That is, the reference signal is a quarter of the vertical synchronizing signal.
In the case of frequency division, as shown in FIG. 1, a reference signal is formed by using the rising edge of the vertical synchronizing signal as a trigger, and a sampling signal that is at the H level from the rising edge of the reference signal to the rising edge of the first vertical synchronizing signal is formed. In addition, after the rising edge of the reference signal, 3 from the rising edge of the first vertical sync signal.
A take-in signal that makes the level to the rising edge of the second vertical synchronizing signal H level is output, and after the output of the take-in signal is stopped, a clear signal that makes the H level until the rising edge of the next reference signal is output.

The peak hold circuit formed in the gate array 31 is operated by the sampling signal, and the peak hold circuit operates when the sampling signal is at the H level.
The 4-bit image data output from the device is fetched, and the maximum value of the fetched image data is stored.

Therefore, in this embodiment, the maximum value of the brightness in the video signal for one field is detected once every two frames, and the maximum value in this one field is stored in the peak hold circuit. In this embodiment, the 4-bit image data output from the CCD camera interface 13 is written to the RAM 29 or the V-RAM 33 through the gate array 31 when the fetch signal is at the H level, and the fetch signal is at the H level. At this time, the amplification factor of the operational amplifier 12 is changed based on the maximum value stored in the peak hold circuit.

That is, as the amplification factor of the operational amplifier 12,
It is also possible to predetermine the initial values for indoor and outdoor, and when the most significant bit (4th bit) of the maximum value stored in the peak hold circuit is 0 with respect to this initial value, , The amplification factor is doubled, the third bit and the second bit are discriminated when the fourth bit is 1, and the initial value is set when the third bit and the second bit are 00 (binary). On the other hand, the amplification factor is increased by 60%, and the third and second bits are 0.
The amplification factor is changed so that when it is 1 (binary number), it is increased by 20%, and when it is 10 (binary number), it is increased by 10%.

In this way, by changing the amplification factor of the operational amplifier 12, for example, a conversion is performed so that the value of 5 volts of the video signal amplified by the operational amplifier 12 corresponds to F (hexadecimal) of 4-bit image information. When the interface 13 is used, the image information is VR by the capture signal.
When stored in the AM 33, when the entire field of view of the CCD camera 11 is dark and the peak value in the frame of the video signal amplified by the operational amplifier 12 is 2 volts, if the amplification factor of the operational amplifier 12 is the initial value, The 4-bit image data has a maximum value of 6 (hexadecimal number) and a brightness ratio of 7 levels on the entire screen, but is converted to 4-bit because the peak value of the video signal in one field is 2 volts. If the maximum value of the image data is 0110 (binary number),
In this embodiment, the peak hold circuit detects and holds 0110 (binary number) as the maximum value in one field in which the sampling signal is at the H level.
In the next two fields in which the capture signal is output based on this maximum value, the amplification factor of the operational amplifier 12 is doubled, and if the brightness does not change significantly in an extremely short time (within 1/30 second), the CCD camera The peak value of the video signal input to the interface 13 can be set to 4 volts, and C
The CD camera interface 13 outputs 4-bit image data in which the brightest point on the entire screen is D (hexadecimal number), and the brightness of the screen displayed on the LCD 41 can be monitored in 14 steps and a still image can be displayed. When recording, high quality image data can be left.

Then, the maximum value stored in the peak hold circuit is cleared to zero by the clear signal, and again, the maximum value in the image data in one field from the rising of the reference signal is detected and stored in the peak hold circuit, and the next two fields 1 Since the LCD display is performed by the image data of the frame and the image data is recorded, it is possible to always record a high-resolution screen.

In the above embodiment, the vertical synchronizing signal is divided into quarters.
Whether the frequency is divided into the reference signals or divided into ⅙, as shown in FIG. 2, the sampling signal is output for the first field, and the sampling signal is followed by the acquisition signal for one frame period. By outputting
The video signal, which is an analog signal, can be changed into 4-bit image data every three frames.

Further, when dividing the vertical synchronizing signal, if the vertical synchronizing signal in the even field is detected and the reference signal is raised, the peak value in the second field is detected,
As the image data, one frame of image data can be recorded in the order of the first field and the second field.
Incidentally, in the image processing in this embodiment, the image signal to be displayed on the LCD 41 is created by capturing the video signal for one frame every several frames, the image is projected, and the image is appropriately recorded. Even if it becomes discontinuous, displaying all the data of a television signal of 60 fields per second on the LCD 41 as a multi-gradation cannot follow the reaction speed of the liquid crystal, and when recording image data on the IC card 17 or the like, the monitor of the LCD 41 can be used. In contrast to the case where the screen is disturbed, the LCD 41 can form an image of about 4 to 15 screens per second based on the image data once for every 2 frames or 4 to 8 frames as in the present embodiment. Make the display beautiful, especially once every 6 frames, that is, capture 5 or 6 screens of image data per second,
Displaying an image with this image data has the advantage that the screen is easy to see and monitor is easy.
It is not necessary to provide a sensor or the like for detecting the brightness in the visual field of the camera 11, and there is an advantage that the recording device 10 is downsized and current consumption is not increased.

[0019]

According to the present invention, when displaying on the LCD based on the video signal output from the CCD camera, the LCD is operated by the image information for one frame in every several frames.
1 in the frame that is not displayed
Since it is a method of adjusting the conversion rate from the video signal to the image data based on the maximum value of the image data in the field, the brightness of the screen is detected without providing an illuminance sensor separately from the CCD camera and multi-gradation Image data that forms an image can be created, and image data that can clearly identify the light and dark in the image can be easily formed.

[Brief description of drawings]

FIG. 1 is a time chart showing a control signal of a method according to the present invention.

FIG. 2 is a time chart of control signals showing another embodiment of the method according to the present invention.

FIG. 3 is a block diagram of a recording device for performing the method according to the present invention.

FIG. 4 is an external view of a recording apparatus that carries out the method according to the present invention.

[Explanation of symbols]

 10 Recording Device 11 CCD Camera 12 Operational Amplifier 13 CCD Camera Interface 21 Main Central Processing Unit 23 Auxiliary Central Processing Unit 25 Program Read Only Memory 27 Font Read Only Memory 29 Random Access Memory 31 Gate Array 33 Random access memory for video 35 Input / output device 41 Liquid crystal display panel 42 Liquid crystal display panel control device

Claims (1)

[Claims] 1. An image is displayed on a liquid crystal display panel by image data obtained by converting an analog video signal output from a CCD camera into a digital signal, and the image data displayed on the liquid crystal display panel is every few frames. The maximum value of the image data in one field in the frame not displayed on the liquid crystal display board is detected, and the conversion rate at the time of analog-digital conversion of the video signal of the frame for image display based on the maximum value is detected. A method of forming an image signal for a liquid crystal display, which comprises adjusting.