Abstract:
A method for exposing photographic paper is disclosed that utilizes existing DPE processing labs. The method comprises illuminating a light transmittance device, the light transmittance device being controlled to display a digital image to be printed onto the photographic paper. The photographic paper is then exposed with the light transmitted through said light transmittance device.

Description:
TECHNICAL FIELD 
     The present invention relates to the printing of photographs from digital images, and more particularly, to the printing of digital images using existing DPE mini labs. 
     BACKGROUND 
     The use of digital still cameras (DSC) has exploded in recent years. A digital still camera can take an electronic or digital image using the camera&#39;s image sensor and store the image digitally in some type of memory medium. As the resolution of digital still cameras have increased, the quality of the digital image is now sufficient in many circumstances to displace photographs taken by conventional photographic film. 
     Once the digital image has been captured by the DSC, the digital image is transferred to a personal computer. At that time, the photographer can electronically manipulate the image, such as by cropping, exposure control, zoom, etc. In order to get a physical photographic print, typically the photographer will print the digital image on a printer. The capital and consumable cost for the personal computer, printer, paper, and ink can be relatively expensive when compared to photographic film processes. 
     For example, a person with a digital still camera would require a personal computer and a printer to have a physical print of the digital images. Alternatively, the user may transmit the digital images to a third party that may perform the printing function. In any event, the process is still relatively expensive. 
     The process for developing and printing from photographic film is well known. For example, after the film has been exposed by capturing images using a camera, the film is provided to a film processor, which develops the film into a “negative”. The developed negative film is then used to print photographs, typically using an exposure and development process for the photographic paper. Because of the extensive previous use of photographic film, the technology developed for the processing of photographic film and prints is well established. Thus, the price of each photograph is now relatively low. 
     Additionally, in many parts of the world, completely self-contained “minilabs” are prevalent. These minilabs are also referred to as a DPE. The DPE equipment represents a fairly high capital expenditure that has been already invested to service the photography market that uses conventional photographic film. The transition from photographic film to digital imagery risks rendering this capital expenditure obsolete. An example of a DPE minilab is shown in U.S. Pat. No. 5,583,610 to Yoshikawa. As seen in FIGS. 2 and 3 of the &#39;610 patent, the processing apparatus includes an exposure portion in which images recorded on a negative film are exposed and a processor portion in which exposed photographic paper is subject to developing processing. Currently, these DPE mini labs are not suited for, nor adapted to, the processing of digital images. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of a prior art photographic film exposure system. 
     FIG. 2 is a schematic illustration of a digital image exposure system formed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     The present invention relates to the retrofitting of a DPE minilab to accommodate the printing of photographic prints from digital images. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. 
     Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     FIG. 1 shows a simplified prior art schematic illustration of system for exposing photographic paper using a negative film. In particular, the system  101  includes a light source  103 , filters  105 , condensing lens  107 , negative film  109 , lens  111  and photographic paper  113 . In operation, the light  103  provides a broad spectrum of light that travels through filters  105  and condenser lens  107 . The filters  105  and condenser lens  107  are operative to condition the light prior to transmittal through the negative film  109 . After the light travels through the negative film  109 , it is focused onto the photographic paper  113  by the lens  111 . Following this exposure process, the photographic paper  113  is then developed using a developing process. The foregoing description is described in greater detail in the &#39;610 patent referenced above and is standard for DPE-type minilabs. Note that the photographic paper  113  is developed in a different portion of the minilab. The developing of the photographic paper  113  in both the prior art embodiment of FIG.  1  and the present invention shown in the FIG. 2 is identical. 
     However, because the DPE minilabs of the prior art require the use of negative film  109 , with the advent of digital images, these DPE mini labs are rendered useless. The present invention seeks to modify the existing infrastructure, i.e., the existing DPE minilabs, to accommodate the use of digital images for generating photographic prints. To a large extent, the required modifications do not effect a large majority of the DPE mini lab structure. For example, the entire apparatus for developing the photographic paper is left undisturbed. Moreover, much of the exposure portion of the DPE mini lab is left unchanged. Indeed, only the negative film  109  is replaced with a liquid crystal display (LCD) or other type of light transmitting device that can be used to selectively display the digital image. The term “display” as used herein is not necessary limited to the visual perception by a human eye, but rather any manipulation of the LCD so as to selectively allow light to be transmitted (or reflected as the case may be) through the LCD in a representative manner to the digital image to be printed. 
     FIG. 2 shows such a modification. In particular, the negative film  109  has been replaced by, in this embodiment, an LCD display  201 . It should be noted that the LCD display  201 , in one embodiment, is capable of reproducing substantially all of the visible spectrum of light, i.e., being able to modulate all of the visible spectrum of light. In such a situation, the filters  105  may in certain circumstances be removed. The LCD display  201  may be a high resolution liquid crystal display comprised of hundreds of thousands, if not millions, of discreet pixels. Each pixel can be electronically controlled to allow the transmittance of light. Moreover, by appropriately applying color filters to the LCD pixels, a full color spectrum can be approximated onto the photographic paper  113 . In other embodiments, the pixels do not require color filters, but rather can directly manipulate the color of the light to be transmitted. Indeed, various types of LCD or other light manipulating apparatus can be used. The only requirement is that the LCD  201  (or equivalent) by able to accept as input the digital image data and configure itself to transmit (or reflect as the case may be) light representative of the digital image. 
     In one specific embodiment, the LCD panel  201  is similar to that used in many laptops and desktop computer displays. In such displays, a fluorescent lamp is used to back light the LCD display and each pixel in the LCD display is modulated in accordance with a desired image to selectively transmit the back lit fluorescent light to the viewer, thereby simulating an image. The same principles are applied to the present invention, where the LCD display  201  can be modulated by the digital image data to allow selective transmission of light from the fight source  103  onto the photographic paper  113 . In this manner, the infrastructure of the DPE mini lab can be used to print photographs of digital images with minor modifications to the apparatus. Moreover, because the digital image is stored in memory, it is much less subject to degradation relative to conventional negative film  109 . 
     While the LCD display  201  may have a variety of spectral characteristics, in one embodiment, it is advantageous to have the LCD display  201  have a spectral profile of the various pixels to ensure high resolution and color image on the actual photographic paper  113 . 
     As seen in FIG. 2, the LCD display  201  can be controlled by a personal computer  203 . The personal computer  203  can receive the electronic digital images and adapt them for presentation onto the LCD display  201 . A photographer can transfer the digital images to the PC  203  in any number of ways. For example, the images can be transferred via email, wireless transmission, physical memory medium, or direct connection to the PC  203 . The PC  203  is operative to selectively cause the LCD display  201  to project to the digital images. 
     Thus, in summary, the DPE minilabs already in existence throughout the world may be retrofitted to generate photographic prints not from negative film, but from digital images. While the specific modifications to the DPE minilabs will vary according to the particular construction of the various minilabs, the modification would generally only involve the substitution of the negative film mounting and handling apparatus with the LCD display  201 . Undoubtedly, orientation and focusing would be necessary to ensure good quality prints. 
     Further, while a PC  203  (shown in FIG. 2) is used to control the LCD display  201 , the functions of the PC  203  may be incorporated into the electronic control apparatus of the minilab. The vast majority of minilabs include some type of computer control. This computer control can easily be adapted to handle the input of digital images and the control of LCD display  201 . From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.