Abstract:
Image acquisition device, method and computer program for digital image acquisition, where the image acquisition device comprises an actuated user interface, where the image acquisition device receives control information from a user indicative of actuation of the user interface, initiates an image acquisition process by receiving lighting data on its sensor and detecting light information. A processor in the image acquisition device analyzes then the detected light information and converts these to image data and acquires image data related to at least two different light configurations, where at least one of the light configuration comprises an image acquired by means of a flash output in the image acquisition device.

Description:
RELATED APPLICATION 
   This application claims priority under 35 U.S.C. §119 based on U.S. Provisional Application No. 60/945,426, filed Jun. 21, 2007, the disclosure of which is hereby incorporated herein by reference. 

   TECHNICAL FIELD 
   Embodiments disclosed herein may relate to the field of digital photography. 
   BACKGROUND 
   When using a camera for making photographs in low light conditions, be it an analog or a digital camera, one is confronted with a common problem of whether to use a usually built-in flashlight or to photograph without the flashlight (e.g., with or without the “flash”). 
   Usually, the user of the camera chooses to take two shots, one with and one without the flashlight, or vice versa. However, this method has the disadvantage of taking two different shots, since the camera will have to be moved when turning on the flashlight and taking the next picture. Additionally, the object to be photographed may have moved after the first picture was taken. This may be a problem with living objects, such as animals or human beings. 
   Also, while in older analog cameras, the end result is not seen until the film is developed. In some analog cameras of the active-pixel sensor type (APS-type) a preview of the picture may be seen before the film is developed. In a digital camera, a preview of the end result may be seen in the camera display, but usually this is not possible for a photograph which is intended to be taken with a flashlight. 
   By the same token, sometimes the photographer is interested in retaining the atmosphere seen in the scenery on the photograph and objects in the background, while sometimes he or she may be interested in details in the foreground. 
   Some solutions exist to the too dark/too bright photograph problem, such as when a picture is taken without and with flashlight. 
   These solutions are mostly based on using the exposure compensation function, by taking two or more pictures where some of the photographs are underexposed and some overexposed. The user may then select the pictures he or she thinks is the best one or let the camera processor calculate a mean exposure picture representing the best picture. 
   The same procedure may be performed with the white balance function on a digital camera. A common term for the taking of multiple photographs using by changing one parameter is bracketing. 
   SUMMARY 
   One ore more embodiments may be related to a digital image acquisition device manually controllable by a user, including an actuated user interface unit for initiating an image acquisition process; an optical sensing unit for detecting light information; and a processing unit for analyzing detected light information and converting these to image data wherein the processing unit is, when the interface unit is actuated, arranged to acquire image data related to at least two different light configurations. 
   Another aspect of one or more embodiments may be related to a method for digital image acquisition comprising a manually controllable image acquisition unit including an actuated user interface unit, the method comprising: a) receiving control information from a user indicative of actuation of the interface unit; b) initiating an image acquisition process; c) detecting light information; d) analyzing detected light information and converting these to image data; e) acquiring image data related to at least two different light configurations. Yet another aspect of one or more embodiments may be related to a computer program for digital image acquisition adapted to be executed in a manually controllable image acquisition unit including an actuated user interface unit, the method computer program comprising instruction sets for: a) receiving control information from a user indicative of actuation of the interface unit; b) initiating an image acquisition process; c) detecting light information; d) analyzing detected light information and converting these to image data; e) acquiring image data related to at least two different light configurations. 
   These and other advantages of some embodiments disclosed herein will be more clearly understood by means of the following detailed description and the accompanying drawings. 

   
     SHORT DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates an exemplary digital camera in which embodiments disclosed herein may be implemented. 
       FIG. 2  illustrates a backside view of the exemplary digital camera according to a first embodiment disclosed herein, with two pictures taken. 
       FIG. 3  illustrates an exemplary mobile terminal including a camera according to one or more embodiments disclosed herein. 
       FIG. 4  illustrates a view of the viewfinder of the exemplary mobile terminal camera according to one or more embodiments disclosed herein, with two pictures taken. 
       FIG. 5  illustrates an exemplary process according one embodiment of a method. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Embodiments disclosed herein may reduce some of the problems related to known technology. 
     FIG. 1  illustrates the front and back of an exemplary digital camera  100  in which embodiments disclosed herein may be implemented. 
   The digital camera  100  may include a body  110 , a lens  120  connected to the body  110 , a flash output unit  130  which in this illustration is integrated in the camera body  110 , a shutter release button  140  on top of the body  110 , an assist light  150  and an optical viewfinder  160 . Moreover, the camera  100  may include a digital sensing unit  170 , a processing unit  180  and a memory  190 . 
   The camera body  100  may be made of any material suitable for a camera and may also have other shapes than the example shape in  FIG. 2 . The camera body will not be elaborated further here. 
   As far as the lens attached to the camera body  100  is concerned, it may have any kind of structure, e.g., a fish-eye, wide-angle, macro, tele or, any other suitable lens. The function of the flash output unit  130  is to illuminate the motive to be photographed. Especially in low lighting conditions the flash output unit  130  may become active. Also, the output power for the light coming from the flash output unit  130  may be regulated manually or automatically by the digital camera 
   In the embodiment of  FIG. 1 , the flash output unit  130  may be located on the front of the camera body  100 , but the camera according to one embodiment may include the flash output unit on any other suitable part of the camera body  100  or be an external flash output unit (not shown) attachable to the camera body  100 . 
   The shutter release button may be situated on the upper part of the camera body  100 . The shutter release button  140  may be located on any part of the camera body and not necessarily only on the top of it as shown in  FIG. 1 . 
   One other element on the front part of the camera body may be the assist light  150  aiding the camera  100  to focus on an object. Sometimes the lighting conditions can be difficult, especially when in low light which may present difficulties for an autofocus function in the camera. Using the assist light  150 , a beam of light may be projected onto a part of the object to be photographed making it easier to obtain a sharp picture of the object even under difficult lighting conditions. 
   Also, the camera body  100  may include an optical view finder  160  for allowing a user of the camera to see the whole or part of a motive as seen through the lens  120 . Sometimes, the view through the optical viewfinder may comprise a square or rectangular bracketed area indicating the area of the motive to be captured by the camera. The optical viewfinder  160  in the camera body  100  may or may not comprise this area, as needed. 
   Furthermore, the camera  100  may include a sensing unit  170  located in this example behind the camera lens  120 , where the sensing unit  170  may comprise a photo detector. The function of the photo detector may be to register intensity variations in light reflected from a motive and passing through the camera lens  120 . The sensing unit may include any light sensitive unit able to convert intensity variations in light reflected from an object to current values. 
   Connected (not shown) to the sensing unit in the inner part of the camera housing  110  may be a processing unit  180  whose task, among others, may include evaluating the current values received from the sensing unit  170  and with the help of filters and image processing algorithms convert these values to a color picture. The way this operation is performed may vary, but is essentially known to the skilled person and will not be explained in detail. Also, the processing unit may, in one embodiment, only perform conversion of the intensity values to a color picture without any further image processing, e.g., converting the intensity information to a so called RAW-picture format. The processing unit may, for example, be an ASIC (Application Specific Integrated Circuit) or some other processing unit able to evaluate intensity information from a sensing unit and to perform image processing algorithms on this information. 
   After the intensity information is converted to a color picture, which may or may not be processed further, the picture may be saved in a memory  190 , which may be an internal memory of the camera, e.g., a RAM (Random Access Memory), a Flash ROM (Flash Read Only Memory) or some other type of internal memory or an external memory, such as usually available in the form of memory cards or hard disks of appropriate size. 
   In the lower part of  FIG. 1  the back side of the exemplary camera housing  110  is shown. The back side may include the already described optical viewfinder  160 , a digital viewfinder  192 , and user interface of the camera  193  that may include one or more buttons for selecting different functions in the camera  100 . 
   The digital viewfinder  192  may works in a similar way to known digital viewfinders in digital cameras. As digital viewfinders are generally known to the skilled person their function will not be explained further here. The digital viewfinder of a digital camera according to one embodiment may, aside from known functions, present a series of two or more pictures as illustrated in  FIG. 2 . This will be explained more in detail later. 
   The user interface  193  on the back side of the camera may be arranged to provide the user with the possibility of altering a number of parameters, such as selecting a dual capture mode. According to one embodiment, the dual capture mode may be a shooting mode where two pictures are taken in direct sequence, one without the use of the flashlight and the other with the flashlight turned on. However, the order of taking photographs without and with flashlight may be selectable. 
   The dual capture setting on the user interface  193  may also be selected so as to take more than two pictures in rapid sequence, such as taking one without the use of flashlight  130  and the remaining pictures with varying degrees of output power from the flashlight  130 . 
   Apart from the dual capture function according to one embodiment, the user may via the user interface  193  select other shooting modes and parameters, such as white-balance, color space, colors in general, ISO-sensitivity, exposure and other parameters relevant for shooting a picture. As far as shooting modes are concerned the user may choose between a variety of programs, such as shutter-priority and aperture-priority programs, manual programs and other predefined programs, such as macro, landscape or portrait programs. 
   Now, according to one or more embodiments, when the user with the help of the user interface  193  selects the dual capture setting on the camera  100 , the camera may take two or more pictures of the same motive, when the user presses the shutter release button  140 , where at least one of them may be taken with the flash output unit  130  turned off and the rest with the flash output unit  130  turned on. Pictures may be saved in the memory  190  of the camera  100  for later review. In this fashion, the user of the camera may be able to make two or more pictures without and with flashlight of an essentially identical scenery. 
   Then, the user may later decide which pictures he is most satisfied with when connecting the camera  100  to his computer (not shown). 
   However, by using the user interface  193 , the user may also, when selecting the dual capture mode, select the automatic activation of dual capture. This may be useful when the processing unit  180  of the camera  100  via the sensor unit  170  detects an intensity distribution indicative of difficult lighting conditions. Normally, the processing unit detects these conditions by comparing them with well-known intensity distributions stored in the memory  190  of the camera  100 . This may have the advantage of the user not being forced to pay attention to difficult lighting conditions himself and therefore would simplify the taking of two or more photographs without and with flashlight even further. 
   Turning now to  FIG. 2 , the back side of the digital camera from  FIG. 1  according to another embodiment is shown. 
   Here, a digital viewfinder  192  may be arranged to display two consecutive photographs. The left photograph  190  (not illustrated) is taken with the flash output unit  130  turned off, while the right photograph (not illustrated)  200  is taken with the flash output unit  130  turned on. The two pictures may be taken by pressing the shutter release button  140  halfway. In this fashion, the user may quickly see how the final picture without flashlight and with flashlight will look like. At that stage he may easily decide which picture to take or which picture is more desirable when a picture is to be taken during low light conditions, such as in the shade or indoors. 
   Also, the processing unit  180  of the camera  100  may via an exposure metering function decide, when performing metering on an object to be photographed, that the lighting conditions are difficult, e.g., either too little or too much incident light falling on the sensing unit  170 , and automatically start taking at least two pictures, one without flashlight and one with the flash output unit  130  turned on. This function may also be manually selected by the user of the camera  100 . 
   However, there may be more than two pictures taken, such as, for example taking three or more pictures, where one of the pictures is taken without the use of the flash output unit  130 , and the rest with varying degrees of output power for the light from the flash output unit  130 . This series of pictures may be displayed in the digital viewfinder  192  of the camera  100 . 
   In order to provide the user with the possibility to judge the final result of the photographing before taking the actual picture, the camera  100  may provide the function to quickly take two or more pictures in sequence when the user presses the shutter release button halfway  130 , where one picture is taken without the use of the flash output unit  130  and the rest with varying degrees of the output power for the flash output unit  130 . This operation may or may not involve focusing on the object to be photographed. 
     FIG. 3  illustrates a mobile terminal  300  that may include a camera according one other embodiment. 
   In the upper part of  FIG. 3 , the exemplary mobile terminal  300  is shown from the backside. The mobile terminal  300  may include a lens  310 , a flash output unit  320 , a transceiver  330  and a shutter release button  340 . Moreover, the mobile terminal  300  may include a sensing unit  350 , a processing unit  360  and a memory  370  depicted by dashed lines. 
   Seen from the front in the lower part of the  FIG. 3 , the exemplary mobile terminal  300  also may include a display  380 . 
   The lens  310  in the mobile terminal may be equipped with an optical zoom function or not, as preferred. Also, it may comprise glass or a lens made of plastic and basically any type of lens suitable to be used in a mobile terminal. 
   The flash output unit  320  may comprise any type of flash lamp, such as a led-diode flashlight or a light bulb, such as used in conventional compact and SLR-cameras. 
   It should be borne in mind that the choice of the flashlight technology may have an effect on the final result when the picture is taken using the flashlight. 
   As far as the transceiver  330  of the mobile terminal is concerned its function will not be described in detail here, since it is known to the person skilled in the art. 
   Using the transceiver, the mobile terminal  300  may for example send and receive photographs taken with its camera or receive photographs taken by other cameras or mobile terminals. 
   The function of the shutter release button  340 , which in  FIG. 3  may be located on the side of the mobile terminal and its front, may be similar to what is described earlier for  FIG. 1 . 
   Thus, if the user has chosen the dual capture mode for the camera in the mobile terminal  300 , after pressing the shutter release button  340  the camera will take two or more consecutive pictures of the same motive, where at least one of those pictures may be taken by using the flash output unit  320  and the others without using the flash output unit  320 . The pictures may be immediately stored onto the memory  370  of the mobile terminal  300 . 
   As already mentioned for the embodiment of the camera in  FIG. 1 , the camera in the mobile terminal  300  may also take more than two consecutive pictures of the same motive but with varying output power from the flash output unit  320  and at least one picture with the flash output unit  320  switched off. 
   Here, the shutter release button  340  on the front part of the mobile terminal  340  may also perform other functions besides focusing the lens on the object to be photographed and taking pictures, such as flipping through a series of already taken pictures shown on the display  340  of the mobile terminal, or zooming in or out of these already taken pictures. Aside from these functions, the shutter release button  340  on the front and on the side of the mobile terminal may perform any other function suitable to be performed in a mobile terminal. 
   The function of the sensing unit  350  may be similar to the function of the sensing unit  370  in the camera  100  of  FIG. 1 . It may comprise a sensing unit  350  detecting intensity variation in light entering through the lens  310  of the mobile terminal  300 . The sensing unit  350  may slightly differ in size compared to the sensing unit  170  in  FIG. 1  in order to fulfill the space constraints usually dealt with when constructing mobile terminals, such as cell phones or PDAs. 
   A processing unit  360  may, aside from performing exposure metering and image processing functions similar to the operation performed by the processing unit  180  in  FIG. 1 , perform other types of functions more characteristic of a mobile terminal which are known to the skilled person and will not be explained further. 
   The processing unit  360  may, as in the case of the camera  100  in  FIG. 1 , perform exposure metering on a motive and from the light intensity information registered by the sensing unit  350  judge whether it should take one or more pictures with and without flashlight. This may occur when a user of the mobile terminal  300  has pressed the shutter release button  340  halfway. 
   Finally, the display  380  of the mobile terminal  300  may also serve as a digital viewfinder for the camera in the mobile terminal  300 . Using the digital viewfinder a user of the mobile terminal  300  may choose a composition of a picture to be taken and see a possible lighting environment of the picture before it is taken. Also, the processing unit  360  may display the processed pictures on the digital viewfinder after they are finally processed. 
   Turning now to  FIG. 4 , the mobile terminal according to another embodiment is shown, where two pictures in series are taken. 
   On the display or the digital viewfinder  380  of the mobile terminal  300 , two pictures are shown, the left one  385  taken without the use of flashlight  320  and the right one  390  by having the flashlight active. The display  380  may also show more than two pictures, if for example, a series of more than two pictures are taken, where one of the pictures may be taken without flashlight while the others are taken with varying output power for the flashlight  320 . Thus the user may easily compare the results of preserving the atmosphere of the motive when no flashlight was used to various degrees of lighting objects in the foreground and choose the picture he is the most satisfied with. 
   This series of pictures may also be taken rapidly when the user is pressing the shutter release button  340  halfway with no or only fast focusing on the object to be photographed, thus showing a preview of the final result before the actual picture is taken. 
   As already mentioned earlier, the user may choose a “bracketing” function on the camera by selecting one or more parameters to be bracketed. This may include exposure, ISO-sensitivity, aperture and shutter together with varying output powers for the flashlight  320 . 
   The user may also choose to let the camera of the mobile terminal  300  first take a picture without flashlight and then one or more pictures with flashlight in order not to disturb the object (especially humans and animals) before the flashlight is used. 
   Turning now to  FIG. 5 , one embodiment of a method is described. 
   At block  500  a processing unit of a camera receives measurement values in the form of light intensity information from a sensing unit on the lighting conditions for the motive seen through the viewfinder. This light intensity information may be received automatically or after the user presses the shutter release button halfway, for example. 
   Thereafter, at block  510  the processing unit using the received measurement values calculates exposure data for the motive by comparing the received measurement values to predefined measurement values stored in the camera memory. These predefined measurement values may comprise intensity data for some well-known lighting conditions, such as indoor motive, outdoor motive, incandescent lighting, light bulb lighting and many other situations. The exposure data may comprise lens aperture, exposure time, ISO-values, white balance and some other exposure data which may be relevant for the motive to be photographed. 
   Also, the processing unit may from the received measurement values calculate an intensity distribution and compare it to well-defined intensity distributions store in the camera memory, thus being able to select the correct exposure data for the motive. 
   In the next block, at  520 , the camera, using the calculated exposure data, may take a first picture of the motive seen through the optical or digital viewfinder of the camera. This picture may be taken without the use of the flashlight and will be converted by the processing unit into an image file which may be stored in the camera memory after some image processing may be performed on it. 
   Thereafter, at block  530 , the processing unit may recalculate exposure data for the motive to be photographed by taking into account the use of the flashlight and thereafter use the recalculated exposure data to take a second picture of the motive by turning on the flashlight. After converting the intensity data into an image file the processing unit may store the image file in the camera memory for later examination on a computer or TV-screen. 
   However, in an alternative embodiment of the method according to one or more embodiments, the images taken with and without the flashlight are saved to the memory of the digital camera at a later stage. 
   In this alternative embodiment displayed in  FIG. 5  by dashed lines, the processing unit of the camera displays at block  540  both pictures (with and without the flashlight turned on) on the digital viewfinder of the camera. 
   It should be mentioned here, that the processing unit may additionally, already after detecting difficult lighting conditions in the motive to be photographed, automatically decide to take two or more pictures of the motive, where at least one of the pictures may be taken by turning on the flash output unit. This may occur after pressing the shutter release button on the camera halfway. In this fashion the early detection of difficult lighting conditions may aid the user in rapidly opting for the “right” picture. 
   Difficult lighting conditions for the camera may comprise too many high and/or too many low measurement values or extreme differences between the highest and the lowest measurement values. 
   When speaking about high and low measurement values in the form of intensity values received from the sensing unit of the camera, a high value may correspond to an intensity value near a maximum intensity value the sensing unit can register. Conversely, a low intensity value may correspond to a value near the lowest intensity value the sensing unit is able to register. 
   Examples of difficult lighting conditions may be low light, such as in an indoor motive, candlelight and many dark areas in the motive, direct sunlight behind the object to be photographed making the object appear dark, light reflections from shiny surfaces, such as water, glass or metal or too high a contrast between the darkest and the lightest areas in the motive. 
   At block  550 , the camera may wait for the user to select one of the pictures displayed by for example using the user interface of the camera and pressing the shutter release button completely. 
   If the user is not satisfied with either of the pictures taken, the processing unit in the camera may return to the exposure metering block  510 . 
   Otherwise, if the user has chosen one or all of the pictures shown in the digital viewfinder of the camera, the processing may take all of the pictures in sequence, processes them and stores them in the camera memory, block  560 . 
   It should be emphasized that the term “comprises/comprising” when used in the this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. 
   It will be appreciated by the skilled person that various modification of the present invention are possible and that the above presentation should be taken as limiting for the present invention. Ultimately, the scope of the present invention is only limited by the accompanying patent claims.