JP3837897B2 - Digital camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital camera.
[0002]
[Prior art]
Conventionally, digital cameras capable of recording image data in a compressed mode and a non-compressed mode are known. A digital camera that can transmit image data to a device such as a personal computer via a modem is also known.
[0003]
[Problems to be solved by the invention]
However, in the conventional digital camera, no consideration is given to the optimization of data at the time of image data transmission, and the image data remains as it is, that is, the image data in the compression mode remains compressed, and the image data in the non-compression mode. Was sent uncompressed. For this reason, there is a problem that it may take time to transmit the image data.
[0004]
Therefore, an object of the present invention is to provide a digital camera that can shorten the transmission time by optimizing the image data at the time of transmission.
[0005]
[Means for Solving the Problems]
The above-described problems include a mode for transmitting image data and a compression control unit for image data, a mode for compressing and recording image data of a captured image on a memory card, and a memory card as an uncompressed image In a digital camera capable of selecting a recording mode, image data to be transmitted is image data compressed and recorded on a memory card or image data recorded on a memory card as an uncompressed image A determination means for determining whether the image data is recorded as an uncompressed image on the memory card, the image data is compressed via the modem in a state compressed by the compression control means. This is solved by adopting a transmission configuration.
Further, the image data compression control means is provided, and a mode for compressing and recording the image data of the photographed image on the memory card and a mode for recording on the memory card as an uncompressed image can be selected. In a digital camera capable of transmitting image data via the image data, the image data to be transmitted is image data compressed and recorded on a memory card or image data recorded on a memory card as an uncompressed image A determination means for determining whether the image data is recorded as an uncompressed image on the memory card, the image data is compressed via the modem in a state compressed by the compression control means. This is solved by adopting a transmission configuration.
Further, the compression control means may employ a configuration in which uncompressed image data is compressed by the JPEG method.
In addition, it is preferable to adopt a configuration in which tag information including the presence / absence of compression is attached to the image data and it is determined whether the image data is compressed by looking at the tag information.
[0006]
According to this digital camera, all image data can be transmitted after being compressed, and the transmission time is shortened.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
First, the configuration of the digital camera will be described.
[0008]
The digital camera 1 is comprised from the box-shaped camera main-body part 2 and the rectangular parallelepiped imaging part 3, as shown in FIGS. 1-3. The imaging unit 3 is detachably mounted on the right side surface of the camera body unit 2 when viewed from the front (the front side in FIG. 1), and is rotatably mounted in a plane parallel to the right side surface.
[0009]
The imaging unit 3 includes an imaging device including a photographic lens 301 having a macro zoom and a photoelectric conversion device such as a CCD (Charge Coupled Device), and an optical image of a subject is converted by a charge signal photoelectrically converted by each pixel of the CCD. The image is converted and captured. On the other hand, the camera body 2 has a display unit 10 made of an LCD (Liquid Crystal Display), a memory card 8 mounting unit 17 and a connection terminal 13 to which a personal computer is externally connected, and is mainly captured by the imaging unit 3. After the image signal is subjected to predetermined signal processing, processing such as display on the LCD display unit 10, recording on the memory card 8, and transfer to a personal computer is performed.
[0010]
A macro zoom lens 301 is disposed inside the imaging unit 3, and an imaging circuit including a CCD color area sensor 303 is provided at an appropriate position behind the macro zoom lens 301. In addition, a dimming circuit 304 including a dimming sensor 305 that receives reflected light from the subject of flash light is provided at an appropriate position in the imaging unit 3. As shown in FIG. 1, a grip portion 4 is provided at an appropriate position at the left end portion, and a built-in flash 5 is provided at an upper appropriate position at the right end portion, as shown in FIG. Further, as shown in FIGS. 1 and 2, switches 6 and 7 for frame advance when reproducing a recorded image are provided on the upper surface of the camera body 2 as shown in FIGS. The switch 6 is a switch (hereinafter referred to as an “Up key”) for feeding a recorded image in a direction in which the frame number increases (in the shooting order direction), and the switch 7 is a direction in which the frame number decreases in the recorded image. This is a switch for frame-by-frame advance (hereinafter referred to as the Down key). Further, an erasure switch D for erasing an image recorded on the memory card 8 is provided on the left side of the Down key 7 when viewed from the back side (the front side in FIG. 2), and a shutter button is located on the right side of the Up key 6. 9 is provided.
[0011]
As shown in FIG. 2, an LCD display unit 10 is provided on the rear surface of the camera body unit 2 to display a captured image on a monitor (corresponding to a viewfinder) and to reproduce a recorded image. It has been. A slide switch type compression setting switch 12 for switching and setting the compression rate K of the image data recorded on the memory card 8 is provided below the LCD display unit 10. Further, the connection terminal 13 to which a personal computer is externally connected is provided on the side surface of the camera body 2 on the image pickup unit 3 side, and a power switch PS is provided on the upper back.
[0012]
The digital camera 1 has an “auto flash mode” in which the built-in flash 5 is automatically flashed in accordance with subject brightness as a mode related to flash (hereinafter, flash may be referred to as FL) regardless of subject brightness. A “forced light emission mode” for forcibly emitting the built-in flash 5 and a “light emission inhibition mode” for prohibiting the light emission of the built-in flash 5 are provided, and the FL mode is disposed above the display unit 10 on the back surface of the main unit 2. Each time the setting key 11 is pressed, the “automatic light emission”, “forced light emission”, and “light emission prohibition” modes are cyclically switched, and any mode is selected and set. The digital camera 1 can select and set whether or not compression is performed during recording. When the compression setting switch 12 is slid to the right, recording is performed in the non-compression mode, and when the compression setting switch 12 is slid to the left, recording is performed in the compression mode. In the uncompressed mode, data is recorded in a RAW data system in which 8-bit RGB data is arranged in units of pixels, and in the compressed mode, it is recorded in the JPEG format.
[0013]
Furthermore, a shooting / playback mode setting switch 14 for switching between “shooting mode” and “playback mode” is provided at the upper right end on the back of the camera body 2. The shooting mode is a mode for taking a picture, and the playback mode is a mode for playing back and displaying a shot image recorded on the memory card 8 on the LCD display unit 10. The shooting / playback mode setting switch 14 is also a two-contact slide switch. For example, when it is slid to the right, the playback mode is set.
[0014]
A battery loading chamber 18 and a card loading chamber 17 for loading the memory card 8 are provided on the bottom surface of the camera body 2, and the loading ports of both loading chambers 17 and 18 are closed by a clamshell type lid 15. It is like that. The digital camera 1 in this embodiment uses a power source battery E formed by connecting four AA batteries in series as a drive source. Further, a modular jack 2200 for connecting the digital camera to a telephone line is provided on the bottom surface of the camera body 2.
[0015]
FIG. 4 is a block diagram showing a control system of the digital camera 1.
[0016]
In the image pickup unit 3, the CCD 303 receives a light image of a subject formed by the macro zoom lens 301 as an image signal of R (red), G (green), and B (blue) color components (received by each pixel). Photoelectrically converted into a signal consisting of a signal string of the pixel signals thus output. The timing generator 314 generates various timing pulses for controlling the driving of the CCD 303.
[0017]
The exposure control in the image pickup unit 3 is performed by adjusting the exposure amount of the CCD 303, that is, the charge accumulation time of the CCD 303 corresponding to the shutter speed because the aperture is a fixed aperture. If the appropriate shutter speed cannot be set when the subject brightness is low, the inappropriate exposure due to insufficient exposure is corrected by adjusting the level of the image signal output from the CCD 303. That is, when the brightness is low, exposure control is performed by combining the shutter speed and gain adjustment. The level adjustment of the image signal is performed in the gain adjustment of the AGC circuit in the signal processing circuit 313.
[0018]
The timing generator 314 generates a drive control signal for the CCD 303 based on the reference clock transmitted from the timing control circuit 202. The timing generator 314 generates a clock signal such as a timing signal for integration start / end (exposure start / end), a light reception signal readout control signal (horizontal synchronization signal, vertical synchronization signal, transfer signal, etc.) for each pixel, and the like. Output to the CCD 303.
[0019]
The signal processing circuit 313 performs predetermined analog signal processing on the image signal (analog signal) output from the CCD 303. The signal processing circuit 313 includes a CDS (correlated double sampling) circuit and an AGC (auto gain control) circuit, reduces noise of the image signal by the CDS circuit, and adjusts the gain of the AGC circuit. Adjust the level.
[0020]
The light control circuit 304 controls the light emission amount of the built-in flash 5 in flash photography to a predetermined light emission amount set by the overall control unit 211. In flash photography, the reflected light of the flash light from the subject is received by the light control sensor 305 simultaneously with the start of exposure, and when this light reception amount reaches a predetermined light emission amount, the light control circuit 304 passes through the overall control unit 211. A light emission stop signal is output to the flash control circuit 214. The flash control circuit 214 forcibly stops the light emission of the built-in flash 5 in response to the light emission stop signal, whereby the light emission amount of the built-in flash 5 is controlled to a predetermined light emission amount.
[0021]
In the camera body 2, the A / D converter 205 converts each pixel signal of the image signal into a 10-bit digital signal. The A / D converter 205 converts each pixel signal (analog signal) into a 10-bit digital signal based on an A / D conversion clock input from an A / D clock generation circuit (not shown).
[0022]
A timing control circuit 202 that generates a clock for the reference clock, the timing generator 314, and the A / D converter 205 is provided in the camera body 2. The timing control circuit 202 is controlled by the overall control unit 211.
[0023]
The black level correction circuit 206 corrects the black level of a pixel signal (hereinafter referred to as pixel data) A / D converted by the A / D converter 205 to a reference black level. A white balance circuit (hereinafter referred to as a WB circuit) 207 performs level conversion of pixel data of R, G, and B color components so that white balance is also adjusted after γ correction. The WB circuit 207 converts the level of the pixel data of the R, G, and B color components using the level conversion table input from the overall control unit 211. Note that the conversion coefficient (characteristic gradient) of each color component in the level conversion table is set for each captured image by the overall control unit 211.
[0024]
The γ correction circuit 208 corrects the γ characteristic of the pixel data. The γ correction circuit 208 has, for example, six types of γ correction tables having different γ characteristics, and performs γ correction of pixel data using a predetermined γ correction table according to the shooting scene and shooting conditions.
[0025]
The image memory 209 is a memory that stores pixel data output from the γ correction circuit 208. The image memory 209 has a storage capacity for one frame. That is, when the CCD 303 has n rows and m columns of pixels, the image memory 209 has a storage capacity of pixel data for n × m pixels so that each pixel data is stored at a corresponding pixel position. It has become.
[0026]
The VRAM 210 is a buffer memory for image data reproduced and displayed on the LCD display unit 10. The VRAM 210 has a storage capacity for image data corresponding to the number of pixels of the LCD display unit 10.
[0027]
In the shooting standby state, each pixel data of an image captured every 1/30 (seconds) by the imaging unit 3 is subjected to predetermined signal processing by the A / D converter 205 to the γ correction circuit 208, and then While being stored in the image memory 209, it is transferred to the VRAM 210 via the overall control unit 211 and displayed on the LCD display unit 10. As a result, the photographer can visually recognize the subject image from the image displayed on the LCD display unit 10. In the reproduction mode, the image read from the memory card 8 is subjected to predetermined signal processing by the overall control unit 211, then transferred to the VRAM 210, and reproduced and displayed on the LCD display unit 10.
[0028]
The card interface (I / F) 212 is an interface for writing image data to the memory card 8 and reading image data. Further, the communication interface (I / F) 213 is an interface compliant with, for example, the USB standard for externally connecting the personal computer 19 so that communication is possible. Further, the communication interface 213 is also connected to a modem 220 built in the digital camera so that various data of the digital camera, for example, photographed image data can be transmitted / received to / from the outside through a telephone line. Note that the terminal on the opposite side of the communication interface 213 of the modem 220 is connected to the modular jack 2200.
[0029]
The flash control circuit 214 is a circuit that controls light emission of the built-in flash 5. The flash control circuit 214 controls the presence / absence of light emission, the light emission amount, the light emission timing, and the like of the built-in flash 5 based on the control signal of the overall control unit 211, and the built-in flash 5 based on the light emission stop signal STP input from the dimming circuit 304. Control the amount of light emitted.
[0030]
The RTC 219 is a clock circuit for managing the shooting date and time, and is driven by another power source (not shown).
[0031]
The operation unit 250 includes switches corresponding to the Up key 6, Down key 7, shutter button 9, FL mode setting key 11, compression setting switch 12, and shooting / playback mode setting switch 14 described above. It is controlled by the overall control unit 211 via (I / F) 2500.
[0032]
The overall control unit 211 includes a CPU, and organically controls driving of each member in the imaging unit 3 and the camera main body unit 2 described above to comprehensively control the photographing operation of the digital camera 1. In addition, a RAM 2111 for CPU work and a flash memory 2110 storing a CPU program are provided.
[0033]
As shown in FIG. 5, the overall control unit 211 includes a luminance determination unit 211a and a shutter speed (SS) setting unit 211b for setting an exposure control value (shutter speed (SS)). The luminance determination unit 211a determines the brightness of the subject using an image captured every 1/30 (seconds) by the CCD 303 in the shooting standby state. That is, the luminance determination unit 211a determines the brightness of the subject using image data stored in the image memory 209 in an update manner.
[0034]
The luminance determination unit 211a divides the storage area of the image memory 209 into nine blocks, and calculates luminance data representing each block using pixel data of the G (green) color component included in each block.
[0035]
The shutter speed setting unit 211b sets the shutter speed (integration time of the CCD 303) based on the determination result of the brightness of the subject by the luminance determination unit 211a. The shutter speed setting unit 211b has a table of shutter speeds.
[0036]
The shutter speed is initially set to 1/128 (seconds) when the camera is activated, and in the shooting standby state, the shutter speed setting unit 211b starts from the initial value according to the determination result of the brightness of the subject by the luminance determination unit 211a. Alternatively, change and set one step at a low speed.
[0037]
In addition, the overall control unit 211 performs “low brightness scene”, “medium brightness normal scene”, “medium brightness backlight” in order to perform appropriate shutter speed setting, γ correction, and filtering correction (described later) according to the shooting scene. A scene determination unit 211c that determines four types of shooting scenes of “scene” and “high brightness scene” is provided. “Low-brightness scenes” are scenes that usually require flash-assisted light, such as indoor shooting and night-time shooting, and “medium-brightness normal scenes” are illumination lights (including natural light and artificial light) for the main subject. ) Is a scene that can be photographed without auxiliary light because it is a regular light and its brightness is appropriate. The “medium brightness backlight scene” is suitable for the overall brightness, but the flash light is preferable because the illumination light for the main subject is backlit. The “high brightness scene” is, for example, a clear sky sea. It is a very bright scene overall, like shooting at ski resorts. The determination result by the scene determination unit 211c is stored in the memory 211d.
[0038]
Furthermore, the overall control unit 211 determines whether the captured image is a normal photographed image of a landscape, a person, or the like (hereinafter, this kind of captured image is referred to as a natural image) or characters, diagrams, etc. drawn on a board. An image determination unit 211e that determines whether the image is an image (hereinafter, an image similar to this type of binary image is referred to as a character image) is provided.
[0039]
The image determination unit 211e creates a histogram of luminance data at each pixel position based on the pixel data constituting the captured image stored in the image memory 209, and determines the content of the captured image based on this histogram. In general, a histogram of luminance data of a captured image has a non-uniform luminance distribution and a so-called single mountain distribution having a single peak value in the case of a natural image, but for example, a character drawn on a whiteboard In the case of a character image, the luminance distribution is biased between the white background portion and the black character portion, and a two-peak distribution is obtained. Therefore, the image determination unit 211e determines whether the captured image is a natural image by determining whether the histogram of the luminance data BV (i, j) of the captured image has a single mountain distribution or a two mountain distribution, It is determined whether it is a stroke. This determination result is also stored in the memory 211d.
[0040]
The overall control unit 211 includes a filter unit 211f that performs a filtering process and a recorded image generation unit 211g that generates a thumbnail image and a compressed image in order to perform the recording process of the captured image, and an image recorded on the memory card 8 Is reproduced on the LCD display unit 10, a reproduction image generation unit 211h that generates a reproduction image is provided. When the compression mode is set by the compression setting switch 12, the recorded image generating unit 211g compresses the image data, and the reproduced image generating unit 211h expands to display the compressed and recorded image.
[0041]
The filter unit 211f corrects the high-frequency component of the image to be recorded by the digital filter to correct the image quality related to the contour. The filter unit 211f includes a total of five types of digital filters including a digital filter that performs standard contour correction, and two types of digital filters that strengthen the contour and two types of digital filters that weaken the contour with respect to the standard contour correction. It has.
[0042]
The recorded image generation unit 211g reads pixel data from the image memory 209 and generates a thumbnail image and a compressed image to be recorded on the memory card 8. The recorded image generation unit 211g scans the image memory 209 in the raster scanning direction, reads pixel data for every 8 pixels in both the horizontal direction and the vertical direction, and sequentially transfers the pixel data to the memory card 8 to thereby generate a thumbnail image. Is recorded in the memory card 8 while generating
[0043]
Further, the recorded image generation unit 211g reads all pixel data from the image memory 209, and performs predetermined compression processing by JPEG method such as two-dimensional DCT conversion and Huffman coding on the pixel data to obtain the image data of the compressed image. The compressed image data is generated and recorded in the main image area of the memory card 8.
[0044]
When the photographing is instructed by the shutter button 9 in the photographing mode, the overall control unit 211 is a case where the thumbnail image of the image taken into the image memory 209 after the photographing instruction is given and the compression mode is set by the compression ratio setting switch 12 Generates a compressed image compressed by the JPEG method. Then, both images are stored in a memory card together with tag information about the captured image (frame number, exposure value, shutter speed, compression / noncompression, shooting date, flash on / off data at the time of shooting, scene information, image determination result, etc.) 8 is stored.
[0045]
As shown in FIG. 6, the memory card 8 can store 40 frames of images, and each of the frames 81 to 85 has a tag portion and high-resolution image data compressed in JPEG format (640 × 480 pixels). And image data (80 × 60 pixels) for thumbnail display are recorded.
[0046]
Next, processing when transmitting image data in the reproduction mode will be described with reference to the flowcharts of FIGS.
[0047]
When the shooting / playback mode setting switch 14 is set to the playback side, a selection screen is displayed on the LCD display unit 10 of the digital camera at step (hereinafter, step is referred to as S) 300. As an option,
1: Print 2: Playback 3: Transmission of captured image is displayed.
[0048]
“1: Print” is a mode for printing out a photographed image, and “2: Playback” is a mode for reproducing and displaying the photographed image. “3: Transmission of photographed image” sends photographed image data to a predetermined server.
[0049]
In the initial setting, 1: print is selected, but any option can be selected by pressing the Up key / Down key. When “3: Send photographed image” is selected and shutter button 9 is pressed in S310 (YES in S310), the transmission screen of S320 is displayed on LCD display unit 10 of digital camera 1. Here, the transmission destination can be selected and the transmission destination can be set. In the initial setting, XXX is selected as the destination server. When the FL mode selection key 11 is pressed here, the screen returns to the selection screen of S300. When the shutter button 9 is pressed, the process proceeds to S400 in FIG.
[0050]
On the other hand, as shown in S350, when the shutter button 9 is pressed with an option other than “3: Send photographed image” selected (NO in S310, YES in S350), the option is selected in S360. The corresponding processing is performed, and this routine is exited.
[0051]
If the shooting mode is set by operating the shooting / playback mode setting switch 14 as shown in S370 without pressing the shutter button 9 (NO in S350), the shooting mode is changed to this mode. Exit the routine.
[0052]
When “3: Send photographed image” is selected and the shutter button 9 is pressed, the process proceeds to S400 as described above to detect whether the digital camera 1 is connected to the telephone line. If not connected (NO in S400), an error message prompting connection to the telephone line is displayed on display unit 10 in S410, and this routine is exited.
[0053]
If it is confirmed that it is connected to the telephone line (YES in S400), the server (XXX in this example) selected in S420 is called. The server response is monitored in S430. If there is no response (NO in S430), an error message indicating that the server does not respond is displayed on the display unit 10 in S440, and this routine is exited.
[0054]
If there is a response from the server (YES in S430), the value of the counter k representing the transmission frame number is set to 1 in S450, the tag and image of the kth frame are loaded into the memory in S460, and the tag data In step S470, it is determined whether the image data is compressed. If not compressed (NO in S470), the RAW image data is compressed by the recorded image generation unit 211g in S480, and the image data of the target frame is transmitted in S490. If the image data is compressed (YES at S470), the image data is transmitted as it is. In this way, by checking whether or not the image data is compressed and compressing the uncompressed image data, all the image data is transmitted in a compressed state, so that the transmission time can be shortened.
[0055]
During the transmission of the image data, as shown in S500, the display unit 10 displays that the kth frame data is being transmitted. In S510, it is checked whether data transmission is completed, and transmission is performed until completion (NO in S510). When data transmission is completed (YES in S510), it is determined in S520 whether there is any other data to be transmitted. If there is (YES in S520), counter k is incremented in S530, and the process returns to S460.
[0056]
If transmission of all the frames is completed as a result of the determination in S520 (NO in S520), a message that the transmission is completed and the shutter button 9 is pressed is displayed on the display unit 10 in S540. Then, the process waits until the shutter button 9 is pressed in S550, and if it is pressed (YES in S550), the process returns to the selection screen in S300 of FIG.
[0057]
Although the case of transmitting a still image has been described above, in a digital camera capable of shooting a moving image, the moving image format may be converted into, for example, the MPEG format and transmitted, and this case is also included in the scope of the present invention. It is what
[0058]
【The invention's effect】
According to the present invention, depending on the above, it is determined whether the image data to be transmitted is image data compressed and recorded on the memory card or image data recorded on the memory card as an uncompressed image. When it is determined that the image data is recorded on the memory card as an uncompressed image, the image data is transmitted through the modem in a state compressed by the compression control means. Compared to a conventional digital camera that transmits compressed image data as it is without being compressed, the transmission time of the image data can be shortened.
[Brief description of the drawings]
FIG. 1 is a front view of a digital camera used in a digital camera system according to an embodiment of the present invention.
FIG. 2 is a rear view of the digital camera.
FIG. 3 is a bottom view of the digital camera.
4 is a block diagram showing a control system of the digital camera shown in FIGS.
5 is a block diagram showing a configuration of an overall control unit in the block diagram shown in FIG. 4. FIG.
FIG. 6 is a diagram showing a data arrangement in a memory card.
FIG. 7 is a flowchart showing image data transmission processing in a reproduction mode.
FIG. 8 is a flowchart showing a continuation of the processing shown in the flowchart of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Digital camera 2 ... Camera body part 3 ... Imaging part 8 ... Memory card 9 ... Shutter button 10 ... Display part 12 ... Compression setting switch 211 ... Overall control part 211g ... Recorded image generation part 220 ... Modem 2110 ... Flash memory

Claims (4)

A mode for transmitting image data and a compression control unit for image data, a mode for compressing and recording the image data of a captured image on a memory card, and a mode for recording on a memory card as an uncompressed image In a digital camera that can select
A determination means for determining whether the image data to be transmitted is image data compressed and recorded on the memory card or image data recorded on the memory card as an uncompressed image;
When it is determined that the image data is recorded in a memory card as an uncompressed image, the image data is transmitted via the modem in a state compressed by the compression control means. . A compression control unit for image data is provided, and a mode for compressing and recording the image data of the photographed image on the memory card and a mode for recording on the memory card as an uncompressed image can be selected. In a digital camera that can send image data
A determination means for determining whether the image data to be transmitted is image data compressed and recorded on the memory card or image data recorded on the memory card as an uncompressed image;
When it is determined that the image data is recorded in a memory card as an uncompressed image, the image data is transmitted via the modem in a state compressed by the compression control means. .   The digital camera according to claim 1, wherein the compression control unit compresses uncompressed image data by a JPEG method.   The tag information including the presence or absence of compression is attached to the image data, and it is determined whether or not the image data is compressed by looking at the tag information. The digital camera described.

Images