JPH0937202A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the digital camera at a low cost. SOLUTION: The camera is provided with an image pickup element 101 converting an optical image into an electric signal, an A/D converter 103 converting a signal of the image pickup element 101 into a digital signal, a compression section 104 compressing the digitized image pickup element signal, and a recording section 105 recording the compressed signal, and an output signal from the image pickup element 101 is compressed by the compression section 104 without any modification processing and the compressed signal is recorded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera for recording a digitized video signal.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional digital camera. 6
Reference numeral 01 is an image sensor for converting the optical image formed by the lens 602 into an electric signal, 603 is an A / D converter for converting the signal of the image sensor 601 into a digital signal, and 604 is digitized by the A / D converter 603. A video signal processing unit for converting the signal of the image pickup device into a luminance signal and a color signal, 605 a compression unit for compressing the luminance signal and the color signal, 6
A recording unit 06 records the luminance signal and the color signal compressed by the compression unit 605.

The operation of the conventional digital camera configured as described above will be described. Lens 60
The optical image formed by 2 is input to the image sensor 601 and converted into an electric signal. The electric signal converted by the image sensor 601 is converted into a digital signal by the A / D converter 603. The digitized signal is converted into a luminance signal and a color signal by the video signal processing unit 604, and the compression unit 605.
Compressed with. The compressed luminance signal and color signal are recorded in the recording unit 6
It is recorded at 06.

[0004]

However, the digital camera shown in FIG. 6 requires a video signal processing unit for converting the signal of the image pickup device 601 into a luminance signal and a color signal, which increases the cost of the entire apparatus. Resulting in. Also,
Since the total data amount of the luminance signal and the color signal is 1.5 to 2 times larger than the signal of the image pickup device 601, there is a problem that the capacity of the recording unit 606 is increased accordingly.

In view of the above problems, it is an object of the present invention to provide a low cost digital camera capable of recording many images.

[0006]

According to the present invention, an image pickup device for converting an optical image into an electric signal, an A / D converter for converting a signal from the image pickup device into a digital signal, and a digitalized image pickup device signal are compressed. And a recording unit for recording the compressed signal. The signal of the image pickup device is directly compressed and recorded without being converted into a luminance signal and a color signal.

[0007]

With the above configuration, the video signal processing section can be omitted and the cost of the camera can be reduced. Further, since the output signal of the image pickup device has a smaller data amount than the luminance signal and the color signal, the capacity of the recording unit can be reduced accordingly, and if the capacity is equivalent, more images can be recorded.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the digital camera of this embodiment. In FIG. 1, 101 is an image sensor that converts an optical image formed by the lens 102 into an electric signal,
Reference numeral 103 is an A / D converter that converts the signal of the image pickup device 101 into a digital signal, 104 is a compression unit that compresses the luminance signal and the color signal, and 105 is a recording unit that records the luminance signal and the color signal compressed by the compression unit 104. Is.

The operation of the digital camera having the above-described structure according to this embodiment will be described below. The image sensor 101 converts the optical image formed by the lens 102 into an electric signal, and the A / D converter 103 converts the signal of the image sensor into a digital signal. The digitized image pickup device signal is compressed by the compression unit 104, and the signal compressed by the recording unit 105 is recorded.

FIG. 2 is a schematic diagram showing the structure of the image pickup device 101 and the contents of the output signal. In the image pickup element 101, photodiodes 201 that convert an optical signal into an electric charge are arranged in a grid. The signal from the photodiode is input to the vertical transfer CCD (charge coupled device) 202 adjacent to the photodiode, and is sequentially transferred downward. After that, the horizontal transfer CCD 203
Is transferred to the right by the output signal, converted into a voltage signal by the output amplifier 204, and output. Color filters of Mg, G, Cy, and Ye that pass light in a specific range of wavelengths are attached to the light input surface of the pixel, where Mg is magenta, G is green, and
Cy is cyan and Ye is yellow. That is, four types of signals are output from the image sensor. Also,
Depending on the image sensor, there are also three colors of red, green and blue.

FIG. 3 is a schematic view showing the compression unit 104 in detail. First, four kinds of signals of G, Mg, Cy, and Ye are line-block conversion memories 301 to 304, respectively.
And is output in units of 8 × 8 blocks, for example. Then, the discrete cosine transform (DCT) processing unit 305
At 308, the signal is transformed from the time domain to the frequency domain by the discrete cosine transform. Then, the quantizer 30
9 to 312 and quantized, and coding units 313 to 31
In H.6, the Huffman code is converted. As a result, the compressed Mg, G, Cy and Ye signals (Mg'G ', C
y ', Ye') are obtained.

FIG. 4 is a schematic view showing another example of the compression section. The Mg signal, Cy signal, and Ye signal are subtracted from the subtractors 401 to 401.
After the difference from the G signal is obtained by 403, the line-block conversion memories 404 to 407, the discrete cosine transform (DCT) processing units 408 to 411, and the quantization unit 4 similar to FIG.
The compressed G, Mg-G, Cy-G, and Ye-G signals are obtained by 12 to 415 and the encoding units 416 to 419. In this method, since each signal of Mg, G, Cy, and Ye has a high frequency correlation, the high-frequency component of the difference signal becomes small, and the data amount of the compressed signal can be further reduced.

In the embodiments shown in FIGS. 3 and 4, the signals Mg, G, Cy, and Ye are processed in parallel in order to simplify the description. However, each signal is originally output in time division. Therefore, the time-division processing may be performed. FIG. 5 is a block diagram of a reproducing apparatus for reproducing an image recorded by the digital camera of the present invention. The recorded signal is expanded by the expansion unit 501.
Then, the original image sensor signal is restored. Then, the video signal processing unit 502 converts it into a luminance signal and a color signal, and a D / A converter 503 converts it into an analog video signal, which is displayed on the display 504. In this way, since the video signal processing unit is provided on the playback device side, if the video signal processing technology advances in the future, it is possible to play back past image data with higher image quality simply by replacing the playback device. You can

[0014]

According to the present invention, since the output signal of the image pickup device is converted into digital data and then compressed and recorded as it is, there is no need to provide a video signal processing unit for converting into a luminance signal and a chrominance signal. A cost-effective digital camera can be realized. Further, since the output signal of the image pickup device has a smaller data amount than the luminance signal and the color signal, the capacity of the recording unit can be small and the cost can be further reduced. Further, if the capacity is the same, more images can be recorded.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a digital camera according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a detailed configuration of an image sensor used in the same embodiment.

FIG. 3 is a block diagram showing a detailed configuration of a compression unit in the embodiment.

FIG. 4 is a block diagram showing another configuration of the compression unit in the embodiment.

FIG. 5 is a block diagram showing the configuration of a reproducing apparatus in the embodiment.

FIG. 6 is a block diagram showing a configuration of a conventional digital camera.

[Explanation of symbols]

 101 image sensor 102 lens 103 A / D converter 104 compression unit 105 recording unit

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04N 9/804 H04N 9/80 B 9/808

Claims (4)

[Claims] 1. An image pickup device for converting an optical image into an electric signal, an analog / digital converter for converting a signal of the image pickup device into a digital signal, and an image pickup device signal digitized by the analog / digital converter. A digital camera comprising a compression unit and a recording unit for recording the signal compressed by the compression unit. 2. The digital camera according to claim 1, wherein the image pickup device includes a plurality of color filters on the photoelectric conversion unit and outputs a signal corresponding to each color filter. 3. The digital camera according to claim 1, wherein the compression unit independently performs compression processing for each signal corresponding to the color filter of the image sensor. 4. An image pickup device for converting an optical image into an electric signal, an analog / digital converter for converting a signal of the image pickup device into a digital signal, and an image pickup device signal digitized by the analog / digital converter. A recording device including a compression unit and a recording unit that records the image sensor signal compressed by the compression unit, an expansion unit that expands the image sensor signal compressed by the compression unit, and an expansion unit that expands the image sensor signal. And a video signal processing unit for converting the image pickup device signal into a luminance signal and a color signal, and a reproducing device including a digital / analog converter for converting the luminance signal and the color signal into an analog signal. camera.