JPH0828882B2 - Digital electronic still camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a digital signal processing apparatus for digitally processing a video signal obtained by image pickup by an image sensor and electronically recording / reproducing a still image. The present invention relates to an electronic still camera, and more specifically, to an image processing technique for performing desired editing on the still image.

[Conventional technology]

The conventional electronic still camera performs analog signal processing on the video signal obtained by the image sensor. That is, CC
The video signal read from the image sensor such as D is γ-corrected and the white balance is adjusted, and the luminance signal and the color difference signal are generated in the matrix circuit. Therefore, only the necessary frequency component is obtained, and this is FM-modulated and recorded on the magnetic recording medium.

However, in such a conventional electronic still camera, image pickup to recording are performed by analog signal processing, and there is a limit to image quality improvement due to variation in characteristics of matrix circuit and low-pass filter. It was

On the other hand, in recent years, digital electronic still cameras have been proposed to solve the above-mentioned problems, and are gradually becoming popular.

Although various proposals have been made for the digital electronic still camera, an outline thereof will be described with reference to FIGS. 3 to 5. FIG.

That is, in FIG. 3, a subject optical image incident through an optical system 1 having a photographing lens, an aperture, a shutter, and the like is received by a color image sensor 2 composed of a CCD, and is subjected to well-known horizontal and vertical read scanning. The color signals R, G, and B are read from each pixel of the color image sensor 2, and are converted into digital signals indicating, for example, 8-bit (that is, 256 steps) gradations by the A / D converter 3. In the cell array of the color image sensor 2, as shown in FIGS. 4A and 4B, the ratio of the green (G) portion to the red (R) and blue (B) portions is 2: The color signals R, G, and B are output by forming a pixel with a 1: 1 color filter and performing horizontal scanning readout for each row.

These digitized color signals R, G, B are input to a matrix circuit composed of a wide-area luminance signal generation circuit 4, a low-frequency luminance signal generation circuit 5, color difference signal generation circuits 6 and 7 and an adder 9, and a luminance signal Y And color difference signals RY and BY are formed.

The high-frequency luminance signal generation circuit 4 uses the following expression (1), based on the color signals Rd, Gd, Bd delayed for one horizontal period (1H) and the color signals R, G, B currently read out horizontally. The high frequency luminance signal Yh is generated by performing the calculation of (2).

Yh = 0.25 (B + Rd) +0.25 (G + Gd) (1) Yh = 0.25 (R + Bd) +0.25 (G + Gd) (2) In the above equation, the image sensor 1 currently being read in horizontal scanning is used. When the color signals are the blue signal B and the green signal G, the calculation of the equation (1) is performed, and when the output signals are the red signal R and the green signal G, the equation (2) is calculated.
Is calculated.

The high band luminance signal Yh is supplied to the digital low pass filter 8 having a pass band of 0 to 4.2 MHz shown in FIG.

The low-frequency luminance signal generation circuit 5 uses the following equations (3), (4) based on the respective color signals Rd, Gd, Bd delayed by one horizontal period (1H) and the respective color signals R, G, B obtained by the current horizontal scanning readout. The low band luminance signal YL is generated by performing the calculation of (1).

YL = 0.11 (B-G) +0.30 (Rd-Gd) + G ...... (3) YL = 0.11 (Bd + Gd) +0.30 (R-G) + G ...... (4) Note that the current horizontal scanning readout is a line. When the color signals from the image sensor 1 are the blue signal B and the green signal G, the above formula (3) is calculated, and when the output signals are the red signal R and the green signal G, the above formula (4) is calculated. I do.

Then, the low-frequency luminance signal YL is subtracted from the high-frequency luminance signal Yh in the adder 9, and the luminance signal YL-YH generated by the subtraction processing is 0 to 0.7 MHz shown in FIG. 5 (b).
Is supplied to a digital low-pass filter 10 having a pass band of, and is output as a luminance signal Yc.

The color difference signal generation circuit 6 calculates the following equation (5) based on each color signal Rd, Gd, Bd delayed by one horizontal period (1H) and each color signal R, G, B by the current horizontal scanning read. Thus, the color difference signal RY is generated.

RY = 0.7 (R−G) −0.11 (Bd−Gd) (5) Then, this color difference signal R−Y is 0 shown in FIG. 5 (C).
The signal is supplied to a digital low-pass filter 11 having a pass band of about 0.7 MHz.

The color difference signal generating circuit 7 calculates the following equation (6) based on each color signal Rd, Gd, Bd delayed by one horizontal scanning period (1H) and each color signal R, G, B obtained by the current horizontal scanning reading. Generates the equation difference signal BY.

BY = 0.89 (BG) -0.30 (Rd-Gd) (6) Then, this color difference signal BY is a digital signal having a pass band of 0 to 0.7 MHz similarly shown in FIG. 4 (C). -Supplied to the low-pass filter 12.

Furthermore, in the adder 13, the addition operation of the luminance signals YH and Yc from the digital low-pass filters 8 and 10 is performed,
As shown in FIG. 5 (d), a luminance signal Y including luminance components of high and low frequencies is formed.

The storage capacity is reduced by inputting the luminance signal Y and the color difference signals R-Y and BY of the predetermined frequency components thus generated to the data compression circuit 14 to reduce the number of bits.
The data-compressed luminance signal Y and color-difference signals RY and B
-Y is output to the connector 16 via the input / output interface 15.

The luminance signal Y and the color difference signals RY and BY are stored in the memory card 18 having a semiconductor memory (static RAM), and the input / output interface 17 connected to the memory card 18 is used. Recording and reproduction are enabled by mounting the connector on the connector 16.

In this way, by performing digital signal processing,
It is possible to record and reproduce still photos with clear images by always performing arithmetic processing with uniform accuracy.

[Problems to be Solved by the Invention]

By the way, the digital electronic still camera having the above-mentioned configuration is
Although the image can be taken well, the camera cannot record the title, serial number, shooting date, etc. in a part of the photograph by a method other than the shooting.

When there are many recorded images, the title, reference number, etc. are very convenient for organizing and searching, but with an electronic still camera with a conventional structure, these data can be recorded on the camera side. There wasn't.

Therefore, conventionally, when inserting the title, etc.,
Although it was performed by a regenerator having the function,
In consideration of usability, it is preferable to insert a title or the like by operating the camera at the time of shooting.

In addition, depending on the object to be photographed, not only the subject is simply photographed, but also the person who wants to diversify the image expression by performing mosaic or solarization at the time of photographing.

However, the conventional electronic still camera does not have an editing function for performing mosaic or solarization on the whole image or a part of the image, and thus the camera cannot perform the editing at the same time as photographing.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a multifunctional digital electronic still camera by providing a signal processing circuit capable of performing a function of inserting a title or the like and an image editing function in a video signal processing system. Is to try.

[Means for solving the problem]

In order to achieve such an object, the present invention relates to a video signal processing system of a digital electronic still camera, a memory circuit for storing a digitized video signal, and a part of the video data stored in the memory circuit. While inserting character information such as a title and shooting date and time, the average value of the video data is calculated to form the entire image in a soft focus state, and the color data in the central portion of a plurality of pixels is replaced with the entire complex pixel. As a result, a signal processing circuit for editing the image of the desired portion in a mosaic pattern, a control circuit for selecting the title insertion or editing by the data input means, and the like are provided.

[Action]

In the present invention having such a configuration, the control circuit is selectively driven by operating the data input means provided in the digital electronic still camera at the time of photographing, and the signal processing circuit stores the data in the memory circuit. It is possible to insert a title or the like, edit a video, or the like to the created video data.

Therefore, it is possible to record and reproduce an image excellent in image expression in the digital electronic still camera.

In addition, the multifunctionality eliminates the need for a device for image editing and improves the added value of the digital electronic still camera.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
1 is a circuit diagram of a digital electronic still camera to which the present invention is applied, and the same or corresponding portions as those in FIG. 3 are designated by the same reference numerals. Further, FIG. 2 is a pixel arrangement diagram for explaining an example of the editing function.

First, the configuration will be described with reference to FIG. 1. A CCD image sensor 2 having a color filter arranged as shown in FIG. 4 is arranged behind an optical system 1 having a taking lens, a diaphragm, etc. Color signals R (red), G (green), and B (blue) of each pixel are output by vertical scanning reading.

Since these color signals R, G, B are low-level analog signals, they are amplified to a desired level by the preprocessing circuit 21 and subjected to γ correction, white balance correction and the like.

The A / D converter 3 converts the color signals R, G, B into 8-bit digital signals and stores them in the first buffer memory 22 for each hue.

The luminance / color difference signal separation circuit 23 is configured in the same matrix circuit as the high-frequency luminance signal generation circuit 4, the low-frequency luminance signal generation circuit 5, the color-difference signal generation circuits 6 and 7, and the adder 9, and has a first buffer. Color signals R, G, B stored in memory 22
The high-frequency luminance signal YH, the low-frequency luminance signal YL, and the color difference signals RY and BY are generated based on the above. That is, the luminance / color difference signal separation circuit 23 performs the calculation described in the above equations (1) to (6) to generate luminance signals of the color difference signals RY, BY and YL-YH.

The second buffer memory 24 stores the luminance signal and the color difference signal, and the data compression circuit 14 reduces the number of bits of the luminance signal Y, the color difference signals RY and BY, and a memory cartridge described later. It is provided to reduce the storage capacity of the memory. The data-compressed luminance signal Y and color-difference signals RY and BY are output to the connector 16 via the input / output interface 15.

On the other hand, a memory cartridge 31 is connected to the connector 16 and is configured to store the luminance signal Y and the color difference signals RY and BY. That is, the memory cartridge 31
The interface 32, a memory card 33 including a semiconductor memory (for example, static RAM), a power supply battery (not shown), and the like.

By connecting the memory cartridge 31 to the connector 16, the luminance signal Y, the color difference signals RY and BY supplied through the interface 32 at the time of photographing are stored in the image data storage area A of the memory card 33. To do.

Further, during reproduction, the image data stored by the operation of the system controller 42 described later can be read and displayed on a display (not shown).

In addition to the image data storage area A, the memory card 33 has an area B for storing storage capacity, storage content, battery expiration date, and the like.
Is also formed so that the image data and the memory card 33 can be easily managed.

The data input device 41 is attached to the side surface of the case of the electronic still camera at a position where it is easy to operate, and inserts characters and the like with push buttons and the like, edits such as mosaic and solarization
Further, it is configured so that selection of shooting and reproduction can be performed.

The system controller 42 (control circuit) is composed of a microprocessor or the like that centrally manages operation timings from recording to recording on the memory card 33, reading from the memory card 33, and further image editing. That is, when the image editing is selected by the operation of the data input device 41, the system controller 42 drives the character insertion / image processing path 43 to perform the editing operation.
Further, when photographing or reproduction is selected, the system controller 42 drives the interface 15 to control writing of image data to the memory card 33 and further reading.

The character insertion / image processing circuit 43 accesses the first buffer memory 22 when inserting simple character information such as a title and date into an image, and accesses the second buffer memory 24 when performing image editing. Then, the desired editing is performed.

Next, the circuit operation of the digital electronic still camera configured as described above will be described.

First, when a shutter release button (not shown) is pressed to instruct shooting, the optical system 1 is set to an optimum shooting state, and the system controller 42 instructs the image sensor 2 to start scanning and reading.

The color signals R, G, B output from each pixel in time series by the scanning and reading are amplified to a desired level in the preprocessing circuit 21, and γ correction, white balance correction and the like are performed. Then, it is converted into a digital signal in the A / D converter 3 and a memory area corresponding to the pixel array is set to set the first area.
Stored in the buffer memory 22 of.

Then, when the reading of all the pixels is completed, the color signal is read and read by the luminance / color difference signal separation circuit 23, and the calculation described in the equations (1) to (6) is performed to perform the luminance signal Y. And color difference signals RY and BY are generated and recorded in the second buffer memory 24. Data compression circuit 14
Performs data compression on the luminance signal Y and the color difference signals RY and BY as described above.

At the time of shooting, the system controller 42 controls the interface 15 to output the image data to the connector 16 side, and the compressed image data is stored in the image data storage area A of the memory card 33 via the connector 16 and the interface 32. It

In this embodiment, the image data recorded and recorded as described above can be subjected to the following image editing.

Next, among the image editing operations, insertion of characters such as a title will be described.

In this case, for example, a push button of the data input device 41 is operated to input a title, date, and the like.

The system controller 42 is a character insertion / image processing circuit.
The control signal is supplied to 43, and the character insertion / image processing circuit 43 accesses the first buffer memory 22. Then, a part of the pixel data in the digital signal for one frame recorded in the first buffer memory 22 is replaced with character data such as a title and a date. The character data may be character information that is considered necessary for organizing a still photograph, and the character information may be white or black.

On the other hand, when soft focus (blurred image) is input by the data input device 41, a control signal is supplied from the system controller 42 to the character insertion / image processing circuit 43 to perform image editing as described below. Be seen.

In this case, the character insertion / image processing circuit 43 accesses the second buffer memory 24, and as shown in FIG.
Pieces of pixel data _{a 1, a 2, a 3} , a 4, a 5, a 6, a 7, a 8, the average value calculating a a ₉ by the number 9 _{(e.g., a 1/9, a 2} /9, and ~a _9/9) and,
The data is replaced with the calculated average value of the nine data.

As a result, the image of the replaced portion of the pixel data of one frame becomes slightly blurred, and soft focus is performed.

When the data input device 41 specifies a mosaic, the character insertion / image processing device 43 uses a buffer memory.
By accessing 24, the nine pixels a _{1 to} a ₉ are replaced with the pixel data of the pixel a ₅ located at the center, for example.

When solarization is designated by the data input device 41, the luminance signal Y and the color difference signal R corresponding to each pixel are
Each lower bit of the data representing -Y, BY (for example, each original signal that is not subjected to solarization processing is 8 bits) is deleted and converted into a small number of bits. As a result, the respective resolutions are reduced and the solarized image can be reproduced.

The image data edited as above is stored in the buffer memory
After being recorded in 24 and compressed in the data compression circuit 14 as described above, it is recorded in the memory card 33 via the interface 15, the connector 16 and the interface 32.

The image editing is performed as described above, but the image editing is not limited to the above-mentioned nine pixels, and the image editing range can be further expanded or reduced.

According to the digital electronic still camera of the present embodiment, it is possible to perform image processing such as editing or replacement by selecting the storage memory in either the front stage or the rear stage of the luminance / color difference signal separation circuit. It is possible to select a memory that can be used as a memory or a memory that can obtain a high-precision and high-quality image and can perform complicated processing. For example, in the case of the storage memory in the preceding stage, since the color filter array information of the solid-state image sensor is directly arranged on RGB or one surface, it is easy to edit and can be realized by a simple circuit. On the other hand, when the storage memory at the latter stage is used, the processing is changed between the luminance signal (Y) and the color difference signals (RY, BY) in order to perform processing on the signal-processed image, or only the luminance signal or Complex processing is possible by processing only the color difference signals. That is, taking the case of synthesizing characters as an example, in the case of synthesizing achromatic (white, black, gray) characters, the level of the character part may be changed regardless of the RGB color. Is easy to use. On the other hand, if chromatic characters are to be combined, it is easy to use the storage memory in the subsequent stage. In addition, Y, RY, B can be used for editing solarization.
Effective control can be performed by controlling the number of bit reductions of -Y separately.

Further, it is also possible to configure so that the range for image editing is designated by the data input device 41.

Further, in the above embodiment, the first buffer memory 22 is provided for inserting the character information, but instead of this, the memory capacity of the second buffer memory 24 is made large, and the character information is inserted by the second buffer memory 24. Alternatively, the buffer memory 24 may be used.

Further, in this embodiment, the case of processing the color signals of red (R), blue (B) and green (G) has been described, but it goes without saying that the same can be applied to the color signals of complementary colors. Yes. That is, not only the R, G, and B filters shown in FIG. 4 but also the luminance signal generation method can be replaced by another method, and the cutoff frequency of each signal can be set appropriately. May be.

〔The invention's effect〕

As described above, according to the digital electronic still camera of the present invention, a captured video signal is digitized and recorded, and at the same time, the character insertion / linkage that is linked with the data input device is performed.
Since the image processing apparatus is configured to access the recorded digital signal and perform character insertion or image editing at a predetermined position of the image data for one frame, the title, date, etc. of the video recorded at the same time as the shooting is recorded. Character information convenient for organizing can be inserted, and further image editing such as solarization can be performed.

By providing the digital electronic still camera with the functions described above, the electronic still camera itself becomes multifunctional, and a special editing device for video editing becomes unnecessary.

In addition, since it is possible to perform video editing at the shooting site according to the shooting image and shooting conditions, it is possible to perform shooting with excellent artistry and more diverse photography, thus increasing the added value of the camera.

[Brief description of drawings]

1 is a circuit diagram of a digital electronic still camera showing an embodiment of the present invention; FIG. 2 is a pixel array diagram for explaining an image editing operation; FIG. 3 is a circuit diagram showing an example of a conventional digital electronic still camera. FIG. 4 is an explanatory diagram showing an arrangement of color filters; FIG. 5 is a characteristic curve diagram showing frequency characteristics of a digital filter. Reference numeral 1 in the figure; optical system 2; image sensor 3; A / D converter 14; data compression circuit 15; interface 16; connector 22, 24; buffer memory 23; luminance / color difference signal separation circuit 31; memory cartridge 32; Interface 33; Memory card 41; Data input device 42; System controller 43; Character insertion / image processing circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area H04N 5/91 7734-5C H04N 5/781 510 F

Claims (1)

[Claims] 1. A solid-state image sensor, an A / D converter for converting a video signal read from the solid-state image sensor into a digital signal, and a luminance / color difference signal forming a luminance signal and a color difference signal based on the digital signal. In a digital electronic still camera having a color difference signal separation circuit and storing the brightness and color difference signals in a solid-state memory, the brightness / color difference signal separation circuit is provided by temporarily storing the digital signal from the A / D converter. And a storage memory for temporarily storing the luminance and color difference signals output from the luminance / color difference signal separation circuit, and the above-mentioned through a data input circuit that is arbitrarily set and operated. A digital feature that includes an image processing circuit that arbitrarily selects one of the storage memories and edits or replaces all or part of the stored digital signal. Child still camera.