Digital electronic camera having an external input/output interface through which the camera is monitored and controlled

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CROSS-REFERENCES TO RELATED APPLICATION

This application is related to commonly owned co-pending U.S. patent application Ser. No. 08/535,562 concurrently filed with the present application and entitled "A Digital Electronic Still Camera Which Receives an Input/Output Control Program Through a Detachable Communication Interface Card," which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital electronic camera and the interfacing of the camera to an external processing device which monitors and/or controls the camera through an input/output interface.

2. Description of the Related Art

Digital electronic cameras are becoming more popular as the size and cost of electronic components continues to go down. However, a disadvantage of digital electronic cameras is that they typically do not possess the ability themselves to provide a permanent hardcopy of an image or picture which was taken.

Japanese Laid-Open Patent Publication 4-980(1992) discloses an interface card usable with an electronic camera which is capable of transmitting data out of an electronic camera. However, this interface is quite limited in the functions which it can perform. The present inventor has recognized a desire to be able to have more flexible and efficient electronic communication with electronic cameras. However, the commercially available interfaces for such digital electronic cameras was recognized by the inventor to be quite limited. U.S. Pat. No. 5,138,458 issued to Roberts et al, which is incorporated herein by reference, discloses that different types of disk formats can be used with an electronic video camera. However, the use of disks does not provide a complete and efficient manner of monitoring, operating, and controlling a camera.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a digital electronic camera capable for efficiently communicating with various devices. It is another object of the invention to provide a digital electronic camera which can communicate using various communication protocols, is capable of transferring image and/or audio signals to a remote monitoring device, is capable of having the status of the camera monitored by a remote monitoring device, and it capable of being controlled by the remote monitoring device.

These and other objects are accomplished by a digital electronic camera which is capable of interfacing with various types of input/output cards which contain a communication control program therein. The communication control program is transferred from the I/O card to the camera and the camera performs communications in accordance with the received program.

The camera is capable of being monitored and controlled by an external device such as a personal computer through the I/O card. Parameters describing the state of the camera such as focus control data, white balance data, brightness data, battery state, and flash state are transmitted from the camera. The camera can receive commands such as a command to capture one or more images, and commands controlling the audio and video encoding processes. Further, image and audio signals can be transferred to and from the camera through the I/O card.

As the camera operates in accordance with an I/O control program which is within the I/O card, there is no need for the camera to be manufactured to have different types of communication control programs. Therefore, the memory within the camera may be smaller and therefore less expensive, and the camera is easily upgradeable as new communication protocols are developed and increase in popularity. By simply inserting a new I/O card, the camera can transmit and receive information in accordance with the new communication protocol without expensive changes to the structure or circuitry which is permanently mounted in the camera.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 illustrates a digital electronic camera constructed in accordance with the invention connected to an image and audio display device, and having a memory card and input/output card connected thereto;

FIG. 2 illustrates the I/O card and the memory card being connected to the camera;

FIG. 3 illustrates the camera connected to various types of monitoring, printing and processing devices including a television, telephone, computers, and printers;

FIG. 4 illustrates a camera constructed in accordance with the invention connected to a computer which is in the same building as the camera;

FIG. 5 illustrates the camera connected to a computer which is located in a building which is different from the building containing the camera;

FIG. 6 is a block diagram illustrating the construction of the camera;

FIG. 7 is a block diagram illustrating the details of the CPU of the camera;

FIG. 8 illustrates details of the I/O card of the camera;

FIG. 9 illustrates the constructions of the files within the memory card;

FIG. 10 is a flowchart illustrating the processing performed when various types of cards are used with the camera;

FIG. 11 is a timing diagram illustrating the coding of image and audio signals;

FIG. 12 is a timing diagram illustrating the decoding of coded image and audio signals;

FIGS. 13A-13C illustrate different manners of constructing the coded image data;

FIGS. 14A and 14B illustrate the manner of coding audio signals;

FIG. 15 is a flowchart illustrating the process of changing parameters used to control the camera; and

FIG. 16 is a block diagram illustrating a circuit for creating evaluation values.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, there is illustrated a digital electronic camera 30 constructed in accordance with the teachings of the present invention. This digital electronic camera is designed to capture still images but can also capture a series of still images in order to create moving pictures in a similar manner as a cam-corder or video camera captures moving images. The camera 30 includes a lens 7, a microphone 1 for obtaining audio, and a flash 20 for illuminating an object to be photographed. The camera 30 includes a card connector 17 for receiving two PCMCIA type cards such as a memory card 16 and an input/output (I/O) card 15 which has a communication line 24 connected thereto. The I/O card 15 allows images, audio, and control information to be transmitted into and out of the camera 30. Connected to the camera 30 is an audiovisual monitoring device including a color LCD panel 31 and an audio speaker 32. Images captured through the lens 7 and from images stored in the memory card 16 along with audio can be displayed and played on the LCD panel 31 and speaker 32, respectively. Additionally, various commands and status information along with any other information such as the status of I/O functions can be displayed on the LCD panel 31. The LCD panel 31 including the speaker 32 is not required to operate the camera and are easily detachable from the camera in order to reduce the size and weight of the camera, if desired.

FIG. 2 illustrates the details of how the cards 15 and 16 are connected to the camera 30. The camera 30 includes a first card connector 17a and a second card connector 17b, both connected to a card interface bus 25. The cards 15 and 16 can be connected to either of the card connectors but are illustrated as I/O card 15 being connected to the first card connector 17a and the memory card 16 being connected to the second card connector 17b. The memory card 16 can be any type of memory device which plugs into the camera. However, the preferred embodiment of the memory card is a PCMCIA flash memory card which conforms to the PCMCIA 2.1/JEIDA 4.2 standard and which can plug into personal computers in order to easily transfer images and sound to a computer. Additionally, the control program for the I/O card may be transferred either from the memory card 16 or preferably, from the I/O card 15 to a memory within the camera 30. As an alternative to having the communication line 24 connected to the card 15, the line 24 may be connected to other parts of the camera through appropriate terminals.

The camera of the present invention is quite flexible in that it can be connected to many different types of peripheral devices. As illustrated in FIG. 3, the camera is connectable to the LCD panel 31 and speaker 32. Alternatively, audio/video outputs from the camera 30 may be connected to a television 37 which is connected to a photograph printer 31. Further, the I/O card 15 may be connected through the line 24 to a telephone 32 which is either a cellular or wireless phone, or a phone connected to a conventional public service telephone network (PSTN), a PBX telephone system or an ISDN. In order to connect the camera 30 the telephone 32, the I/O card 15 or the camera itself must function as a modem. Images captured by the camera can be transferred through the I/O card 15 which functions as a modem connected to an on-line service such as America On Line. This inexpensively allows images to be taken by a person at a first location to be transferred to a file storage device and subsequently viewed by another person at a second location who has access to the image/voice files. As an alternative to having the I/O card 15 function as a modem, the I/O card 15 may function as an RS-232 interface which is connected to a separate modem.

In FIG. 3, the camera 30 is also illustrated as being connected to a desk-top computer 33 or a lap-top portable computer 34. In this case, the I/O card 15 will function as a serial communication connector card such as an RS-232 communication interface. Additionally, the memory card 16 may be inserted into either of the computers 33 or 34. Typically, the portable computer 34 will have built therein a PCMCIA connector to receive the memory card 16 containing images and possibly sound which are recorded by the camera 30. A PCMCIA card reader or peripheral connector will have to be used in conjunction with the desk-top computer 33 to read the information from the memory card 16. The computers 33 and 34 can display the recorded images and sound, may be used to manipulate the images and sound, and may be used to monitor and control the camera. The computers 33 and 34 can be IBM-PC compatibles, Apple Macintosh compatibles, or any other type of computer. The computers are connected to a color printer 35 which prints color photographs of the images captured by the camera or a digital copier 36 which also prints full-color photographs of the captured images.

A feature of the invention is that the digital electronic camera can remotely transmit and receive images from a connected computer and also be monitored or controlled by the computer. FIG. 4 illustrates the camera 30 which is in a first room connected to the computer 33 which is a different room of the same building. In this manner, images of the digital electronic camera 30 can be monitored and stored in the computer 33 and the computer 33 can be used to control and monitor the settings of the camera 30 such as the brightness or luminance of the image, the amount of image compression performed by the camera 30, the white balance of the camera 30, or other operating parameters.

FIG. 5 illustrates that the camera 30 and monitoring computer 33 can be located in different buildings and connected by wires such as through a telephone network or other manner of communication such as by wireless communication. The remote connection of the camera 30 to the computer 33 can be quite useful for monitoring purposes such as for security or safety reasons. By connecting the camera 30 to a Local Area Network (LAN), a plurality of cameras may be connected to a single communication line. Also, the camera of the present invention can be easily used to monitor a baby or other object by an adult who is at home, even if the adult is working on a computer due to the increasing popularity of the displaying of a plurality of windows on a computer. Further, through the use of modems, a telephone call from the computer 33 to the camera 30 can allow for an expensive manner of performing a remote monitoring function. Additionally, a conventional camera moving system can be employed which allows the camera position to be remotely controlled by the computer 33 or other controlling device.

FIG. 6 is a block diagram showing the details of the construction of the camera 30. The microphone 1 is connected to an amplifier/filter 2a, which outputs a signal to an analog-to-digital converter 4. The amplifier/filter 2a reduces the audio signal to the appropriate bandwidth. The analog-to-digital converter 4 operates with an optimum sampling frequency, for instance, at a frequency which is an integer-times of the sub-carrier frequency of an NTSC signal used by the camera. Further, a sampling frequency of the A/D 4 is more than two times the necessary bandwidth. An audio data compression/expansion circuit 3 is used to encode and decode audio signals using known methods of audio encoding such as linear PCM, Dolby AC-3, or MPEG-2 audio encoding. The compressed audio signals are transmitted to a FIFO circuit 13 which functions as a memory and alternatively can be a DRAM. The FIFO circuit 13 includes a section for images and a section for audio. Unencoded digital audio signals from the compression/expansion circuit 3 are transmitted to a digital-to-analog converter 5 and subsequently amplified and filtered by the amplifier/filter 2b. The audio signals included in the signals 26 are then output to a suitable audio generator such as the speaker 32 or a speaker of a television.

An image photographing section 6 of the camera includes a photographing lens 7, a lens opening 8, an image photographing element 9 such as a CCD (charge coupled device) or a MOS-type image photographing element. The CCD 9 in the preferred embodiment has a resolution of 768.times.480 (horizontal.times.vertical). The output of the CCD 9 is transmitted to a circuit 10 which eliminates noise from the analog signal output by the CCD 9. This may be accomplished by a correlative doubled sampler (CDS). The output image signal from the image photographing portion 6 is transferred to an analog-to-digital converter 4 which transmits a digital image signal to a digital signal processing circuit 11 which, for example, performs ordinary and known treatment of the image signal including gamma-compensation, color separation, and generates the luminance signal Y, and color difference signals Cb and Cr in a known manner. An example of the performance of these functions is disclosed in U.S. Pat. No. 5,343,243, which is incorporated herein by reference. Video signals (either analog or digital) are output from the digital signal processing circuit 11 as a video signal 26 which is display by the color LCD panel 31.

An image data compression/expansion circuit 12 can be used to encode and decode the images using known image compression methods which transform the images into and out of compressed formats such as GIFF, JPEG, MPEG or any other known image compression method. Details of image compression which may be used by the camera 30 are disclosed in U.S. Pat. No. 5,414,464 which is incorporated herein by reference. A card interface circuit 14 is connected to the card connector 17 through the card interface bus 25. The card interface circuit 14 controls communications between the camera and the plug-in communication cards which for example may function as a LAN card, a modem card either for a conventional wired telephone system or a cellular phone, a Small Computer System Interface (SCSI) interface, or an ISDN interface, or any other type of communication device. From interface circuit 14, images and audio are output to memory card 16 or I/O card 15. Also, images may also be transferred to interface circuit 14 from cards 15 or 16.

A Central Processing Unit 23 (CPU) controls the operation of the camera and is connected to a mode display 22 which displays various operating parameters of the camera including modes which have been set and operating parameters of the camera. The mode display 22 may be an LCD or LED display. An operating portion 21 through which the user inputs commands such as the command to take a picture when the shutter button is pressed, whether sound is recorded, whether still images or a series of still images forming moving images are recorded, and all other operations of the cameras. A flash 20 which is powered by batteries (not illustrated) is connected to the CPU 23 and is used to illuminate the scene to be photographed. There is a driver 18 which drives a mechanical system of the image photographing portion 6 and performs functions such as focusing and zooming of the lens. The timing signal generator 19 generates various timing signals as images are captured such as a vertical synchronizing signal, a horizontal synchronizing signal, and a CCD synchronizing signal.

Compressed images which are stored in the memory card 16 may be read out of the memory card 16 through the card interface circuit 14 and stored in the FIFO circuit 13. The compressed images are subsequently transferred to the image data compression/expansion circuit 12 which decodes or expands the compressed image signals and transfers the signals to the digital signal processing circuit 11. In the digital signal processing circuit, the luminance and color difference signals are transformed to a NTSC signal and output as a video signal.

Compressed audio information is similarly read out of the memory card 16 and written into the FIFO circuit 13. The encoded audio signals are transferred to the audio data compression/expansion circuit 3 where they are converted to an uncompressed digital form, converted to an analog form by the digital-to-analog converter 5, and amplified and filtered by the amplifier filter 2b. The converted signal is output as the audio signal.

The digital images captured by the camera are used to create exposure controlling evaluation information, automatic focus controlling information, and automatic white balance evaluation information by the CPU 23. Automatic control of the camera is performed using this information. Additionally, this and all other evaluation data, control data, status data, etc., can be output through or stored in the I/O card 15 or stored in the memory card 16. This information may be used, for example, when monitoring the camera in order to determine if an abnormal state exists. Further, the quality of the image can be optimized by changing the number of pixels used to represent an image.

The CPU 23 also performs a clock function for recording the date and time of when the audio and video has been captured. Additionally, a field number may be added to the image data by the CPU 23. Each of the image data, audio data, date, time, and field number may be output through the card interface circuit 14 to either the memory card 16 or I/O card 15.

Details of the CPU 23 are illustrated in FIG. 7. In FIG. 7, the CPU 23 contains a microprocessor 50, RAM 52 for storing various information and serves as a working memory area as calculations are being performed, and a control program storing area 51. The control program storing area 51 includes a section 55 for storing basic routines such as BIOS (Basic Input Output System) routines, and other routines used by the system. The basic routines 55 are stored in a non-volatile memory such as a flash memory, an EPROM, or other type of memory. There is a section of the control program storing area 51 which stores rewritable and optional routines which may be loaded in from the memory card 16 and the I/O card 15. Section 54 may be constructed using the same flash memory as stores the basic routines 55 or may be a separate memory. In order to reduce the size of the chip and reduce the cost of the chip which may be used as the CPU 23, it is desirable to use a flash memory to store the basic routines 55 and the rewritable and optional routines 54. The CPU 23 may either be a single chip or be composed of multiple components. By having a section for rewritable and optional routines, the camera becomes very flexible by allowing the camera to be programmed as desired and there is no need to store routines which are not going to be used. This rewritable and optional routines section is especially useful for the process of inputting and outputting information as there are many different communication protocols which may be used. The control program storing area 51 stores routines which control the fundamental functions of the camera and other functions such as reading out program data, changing parameters within the camera, writing data into the rewritable and optional routines section 54, and any other function of the camera. Supplemental circuitry 53 performs functions which are necessary for the CPU and includes a bus controller, a serial communication controller, an interrupt controller and analog-to-digital converter for monitoring analog signals, and a clock for keeping track of the time and date.

FIG. 8 is a block diagram showing the construction of the I/O card 15. The I/O card, if desired, can include the functions of the memory card 16 if it is provided with a sufficient amount of memory. The I/O card 15 includes a card connector 40 which plugs into the card connector 17 of the camera. There is an attribute memory 41 for storing attributes of the I/O card such as whether the I/O card is a LAN card, a SCSI card, a serial card, a parallel card, an ISDN card, a modem card, includes memory to store images and sound, etc. There is a card interface 42 which interfaces communications between the camera and the I/O card 15 and also contains sufficient memory to store some picture and audio data. The exact size of the memory within the card interface 42 depends on the requirements of a user. An I/O protocol controller 43 serves as the main processor of the I/O card 15 and controls the functions performed within the I/O card. The I/O protocol controller 43 controls communication to ensure conformance with the appropriate type of communication protocol, which corresponds to the information stored in the attribute memory 41. A flash memory 45 contains the I/O card controlling program which is loaded into the rewritable and optional routines section 54 of the control program storing area 51 illustrated in FIG. 7. This control program is transferred to the rewritable and optional routine section 54 after the I/O card 15 is inserted into the camera. The communications which enter and leave the camera through the line 24 pass through an I/O connector 44 which may be any type of connector which is suitable to connect with the line 24.

FIG. 9 is a block diagram showing an example of the organization of files within the memory card 16. As the memory card 16 will be readable by a personal computer such as an IBM compatible or Macintosh compatible computer, the files will be stored according to the corresponding file format such as a DOS format used with IBM PC compatible computers. The memory card 16 contains three images files 60a-60c, two audio file 61a and 61b, and two input/output control files 62a and 62b. As an alternative to storing the illustrated files in the memory card 16, these files may also be stored in t