Abstract:
An electronic view camera integrates a camera head assembly and laptop computer into a tripod mountable unified structure. The rigid frame, that unifies the camera head and computer, accommodates a choice of laptop type computers from a variety of different manufacturers. The open front, back and side design of the rigid frame permits ready access for electrical connections and for access to removable storage devices, keyboard, and pointing device. The computer LCD acts as a large screen viewfinder for the camera and has the “feel” of a professional type view camera rather than the “feel” of a computer system with a photographic peripheral.

Description:
FIELD OF INVENTION 
   The invention relates to the field of electronic or digital cameras and more specifically to tripod mounted view cameras used in professional still photography. 
   BACKGROUND OF THE INVENTION 
   A number of electronic cameras have been recently introduced in the retail still picture camera market. These cameras differ from traditional still cameras because they replace conventional photographic film with a reusable electronic photocell array as the image sensor and an electronic or magnetic memory as the storage medium. The photocell array, located at the focal plane of the camera, generates an array of discrete signal values (pixels) that represent the photographic image. The array of discrete signal values represents the light intensity falling on the image plane at the locations of the photocells that make-up the photocell array. The image can be reconstructed by displaying the set of discrete signal values as a raster array of the pixel intensity on a video display or liquid crystal display (LCD) unit. 
   Most commercial electronic cameras are directed toward the amateur market and are offered at a range of prices that depend on the features provided. For example, the lowest priced versions typically use optical view finders, such as found on conventional cameras, while higher priced units feature LCD (liquid crystal display) view finders that show the camera operator the image generated by the lens in the photocell array. Because consumers generally prefer the convenience of small cameras, electronic camera manufacturers tend to favor small size even at the expense of inconvenience in manipulating the camera controls. Consequently, the control selector knobs tend to be inconveniently small and are used for multiple purposes which makes these knobs less than optimal for professional use. 
   Generally, some form of electronic or magnetic digital storage is provided for storing one or more images for later viewing. If an LCD screen is provided for view finding, the stored images can be recalled for display on the camera&#39;s LCD screen. Optionally, the stored images may be read out electrically to an external device such as a computer for printing or for archival storage. 
   More elaborate models offer user-selectable operating modes such as a choice in pixel resolution, black-and-white or color, and various levels of image data compression for increasing the image storage capacity within the camera. 
   The ability to couple electronic cameras to a computer has resulted in some electronic cameras being used tethered to a computer as a computer peripheral. The computer is used for archival storage and for camera operating mode selection. Selectable operating mode options can include selection of resolution, flash control, shutter speed, and lens aperture. Unfortunately, this tethered configuration results in a photo-imaging system that is not very camera-like but is more like a computer system with a photo-imaging peripheral. The system does not provide the operator with the same “feel” as, or the convenience of, a studio camera to which a professional photographer is accustomed. 
   The limitations imposed on the professional photographer by currently available electronic cameras may be summarized as follows:
         1. inconvenient small control knobs often overloaded with multiple functions;   2. expensive when they include video screen viewfinder, large storage capacity, and easily used manual controls;   3. awkward tethering to a computer; and   4. difficult to set-up, configure, maintain, and use, if tethered to a general purpose computer.       

   It is an object of the current invention to overcome the current state-of-the-art limitations by providing a professional-quality camera with the same ease of use as current tripod-mounted view cameras used by professional photographers. Further, it is an object of the current invention to provide some, or all, of the following attributes:
         1. the “feel” of a tripod mountable professional camera, as opposed to a computer peripheral;   2. easy to set-up and use;   3. economically priced by taking advantage of developments in the information processing and camera industries;   4. configuration options that include features such as
           a) electronic camera head accepting interchangeable lens;   b) camera parameter control for focus, aperture, and exposure time;   c) LCD view-finder equivalent of ground-glass viewer;   d) high capacity image storage;   e) image processing options including tonality and color correction and enhancement, and image data compression;   f) flexible exposure metering;   g) external input/output communication channel for image data transfer; and   h) ability to apply field upgrades through software loading.   
               

   BRIEF DESCRIPTIONS OF THE INVENTION 
   A tripod mountable view camera that is constructed as an integrated unit that includes:
         a) a rigid frame, suitable for mounting on a tripod, for holding a camera head and laptop type computer;   b) a camera head assembly including lens and electronic image sensor module attached to the rigid frame so that the lens can be unobstructedly pointed at a subject, the camera head assembly being computer controllable for one or more functions, the camera head assembly also including a communication port for image and control data; and   c) a laptop type computer attached to the rigid frame and electrically connected to the camera head assembly communication port for function control and for receiving image data, the laptop type computer screen display selectively operating as an image viewfinder.       

   The incorporation of a computer with an electronic camera head on a rigid mount provides a unitized apparatus that has the “feel” of a professional view camera while providing the flexibility of a programmable computer for controlling the camera head, economically providing storage for multiple images, communicating with external devices when necessary, and supporting image processing software. 
   The programmable laptop type computer can programmably assign specific camera function control to single or multiple sequential keystrokes of the keyboard, or to other input devices, for control of such functions as focus, aperture, exposure timing, and zoom. The designation “laptop type computer” or “laptop computer” is used herein to be the generic name for a portable personal computer commonly called a notebook, laptop, subnotebook, pocket, or clamshell computer. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 ( a ) (prior art) shows an external view of a basic electronic camera. 
     FIG.  1 ( b ) (prior art) shows an electronics assembly of an electronic camera. 
       FIG. 2  shows a front, top, back, and side view of the electronic view camera assembly. 
       FIG. 3  a system block diagram of the electronic view camera of FIG.  2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   FIGS.  1 ( a ) and  1 ( b ) are drawings of a prior-art electronic (or digital) camera  100 . FIG.  1 ( a ) is an external view that includes a lens assembly  101  for projecting an in-focus image of a subject onto a photocell array, an LCD view finder  102  for viewing the image captured by lens assembly  101 , and external controls  103  for camera operating mode and shutter control. The external controls  103  are used for controlling the lens and for inputting ancillary parameters (such as exposure mode, compression quality, and aperture size). 
   FIG.  1 ( b ) shows an electronics assembly  104  that is located at the focal plane of camera  100  and includes control electronics  105 , storage subsystem  107 , and image sensor module  106 . Image sensor module  106  typically has at least one CCD or photodiode type pixel sensor array for capturing images as arrays of charges which can be read out as voltage signals. Multiple pixel sensor arrays are used for capturing color images after separating the image by means of a set of filters into a set of color component images (such as red, green, and blue). The length of time for which the pixel array is exposed determines the image signal intensity formed in the pixel array. Either a conventional mechanical shutter controls the exposure time or an electronic shutter controls the amount of time from initialization of the array of pixels to the transfer of the pixel charge to a storage or readout circuit. 
   Because the pixel charge is sensed as an analog voltage, each pixel voltage is converted to a binary quantized signal representative of the charge for storage, read out, or viewing on LCD viewfinder  102  of FIG.  1 ( a ). However, less expensive units may not include an LCD so that a conventional optical viewfinder is used for picture taking while pictures are displayed or printed on an external device. 
   It should be recognized that few industry or user standards exist for electronic (digital) cameras so that considerable variation in configurations of current commercially available products exists. In this regard, Computer Buyer&#39;s Guide, Hams Publications, Inc., New York N.Y., Spring 1998, p.60, col. 1, para. 2, states: “There are no agreed-upon standards because digital cameras are the newest of PC [personal computer] input devices”. This quote is also significant because it shows that the industry&#39;s current state-of-mind about the role of electronic cameras is as computer peripheral devices. 
   It is desirable that an electronic studio (view) camera be made available that allows the professional, and advanced amateur, photographer to operate the electronic camera with the feel of a conventional tripod-mounted studio camera while enjoying all of the benefits of an electronic camera.  FIG. 2  shows a four-view drawing of the mechanical configuration of an electronic view camera  200  that satisfies this requirement according to the present invention described below. 
   Referring to  FIG. 2 , the top view shows a camera head  201  that holds the lens assembly  211  and houses the image sensor module and associated electronics, a laptop type computer  203 , and a rigid mounting frame  202  that holds the camera head  201  and computer  203  as a unified camera assembly. Frame  202  has a bottom plate  207  on which computer  203  is securely affixed. Computer  203  is attached to bottom plate  207  by means of a hook-and-loop fastener but any other reasonable fastener method may be used. All sides of computer  203  are accessible through the openings  208  on the right, left, and front sides of frame  202 . Access openings  208  are provided to allow access to any input/output connector terminals on computer  203 . The backside of frame  202  allows convenient access to computer keyboard  205  by the photographer for keyboard control of camera  200  and for convenient viewing of computer LCD display  204  from a normal viewing position to the rear of camera  200 . The keyboard area  205  can also contain a pointing (or touch-pad) device  213  for selecting menu items displayed on LCD display  204  or for generating camera head  201  control signals. Cable  211  electrically connects camera head  201  and laptop computer  203  for communicating control and image data signals. 
   Camera head  201  can be rigidly attached to frame  202 . However, in the preferred embodiment, the camera head is mounted on swivels  206  that permit the lens to swivel about horizontal axis  209  for permitting the lens to point either upward or downward while computer keyboard  205  and LCD  204  remain conveniently oriented for manual inputs and viewing, respectively. 
   Openings  208  are provided for all sides of computer  203  so that the frame can accommodate a large variety of laptop computer models, virtually independent of manufacturers and manufacturers&#39; models, and allow for easy access to any input and/or output connectors and for inserting or removing compact disks (CDs), floppy diskettes, or card interface devices such as PCMCIA I/O adapters. Opening  208  between camera head  201  and computer  203  provides space for connecting cable  212  between computer  203  and camera head  201 . 
   When electronic view camera  200  is mounted on a tripod, frame  202  can also be used as a grip for panning the camera in place of the tripod pan bar commonly used for positioning a camera through the degrees of freedom of motion of the tripod head. 
   A standard camera tripod mount  210  (a screw hole or mounting plate adapter) is included in bottom plate  207  for connecting a tripod to camera  200 . Tripod mount  210  is located below the approximate center of mass of camera  200  and along the central axis  214  of lens assembly  211 . By aligning tripod mount  210  behind the lens allows the camera to rotate in a manner similar to the familiar view camera when mounted on a tripod, i.e. without additional image shift or parallax that would result from positioning tripod mount  210  off the central axis  214  of lens assembly  211 . Preferably, a mounting plate is used that allows a sliding adjustment of the position of the camera on a tripod head to accommodate the variations in the location of the center of mass of different camera configurations (such as when camera head  201  or lens assembly  211  is changed). 
     FIG. 3  is a system block diagram of camera  200  and is shown to include camera head  201  with attached lens  211  and laptop computer  203 . 
   Camera head  201  includes: lens assembly  211  which may be electrically or manually controlled; image sensor module  312  with one or more photocell arrays; ADC  313  for converting the analog pixel signals from module  312  into binary quantized values; image data buffer  314  for temporary storage of the quantized image data; and control and I/O interface unit  315  for communicating control signals and image data signals over cable  212  which is connected to computer  203 . 
   Computer  203  is shown as a bus-oriented computer organized around system bus  302  that communicates control and data information between computer subassemblies. Within computer  203 , system bus  302  supports CPU  303 , memory  305 , and display (LCD)  306 . In addition system bus  302  also supports input/output (I/O) features such as keyboard  304 , pointing device  310 , I/O port  309 , storage system  307  for bulk storage of software and image data; and removable disk read/write unit  308 . The camera elements controllable by computer  203  include: lens assembly  211  for focus, aperture, and zoom control; image sensor module  312  for initialization, exposure, and resolution control; ADC  312  for quantization of pixel data; image buffer  314  for image storage and retrieval. 
   Software loaded in computer  203  causes camera  200  to operate as an integrated (unified) camera system rather than a computer system with an electronic camera peripheral device. The keyboard function can be customized so that a photographer can, by simple keystrokes, conveniently operate the photographic functions of camera  200  with the feel of a studio view camera. 
   The computer and its software are preferably pre-configured when the camera is manufactured so that the user sees the product only as a camera. As a result, the user does not need to be involved in other complexities of computer usage, such as installing application software. The camera software preferably hides the underlying operating system from the user while relying on the operating system to provide efficient access to modern hardware capabilities such as the LCD screen and mass storage devices. Building the camera around a computer allows a surprisingly large efficiency advantage during the camera development process because new technologies can be quickly integrated into new versions of the camera with only modest effort. With additional software effort, new features can be added to cameras after they are manufactured and in use. Hence, the apparatus as described above allows for rapid and economical product improvements. 
   The above description was limited to specific elements and structures for clarity of explanation of the invention. For example, frame  202  of  FIG. 2 , shown with a particular visual design form, can assume a variety of visual design forms and still perform the function described. Also, a specific common computer architecture was used in the preferred description. However, other well-known computer architectures can be used as will be understood by those skilled in the art. Many other changes in the methods and apparatus described above may be made by the skilled practitioner without departing from the spirit and scope of the invention, which should be limited only as set forth in the claims that follow.