BRIEF DESCRIPTION OF THE FIGURES
In the figures show:
FIG. 1: a flowchart of an exemplary embodiment of a method for emphasizing specific image portions in an image according to the present invention;
FIG. 2: a block diagram of an exemplary embodiment of an apparatus according to the present invention;
FIG. 3: a block diagram of a further exemplary embodiment of an apparatus according to the present invention;
FIG. 4: a flowchart of an exemplary embodiment of a method for identifying specific image portions in an image according to the present invention;
FIG. 5
a: an exemplary image in which image portions are to be emphasized according to the present invention;
FIG. 5
b: an example of a representation of the image of FIG. 5a with emphasized image portions according to an embodiment of the present invention;
FIG. 5
c: a further example of a representation of the image of FIG. 5a with emphasized image portions according to an embodiment of the present invention;
FIG. 6
a: a further exemplary image in which image portions are to be emphasized according to the present invention;
FIG. 6
b: an example of a representation of the image of FIG. 6a with emphasized image portions according to an embodiment of the present invention, where the foreground region is in focus;
FIG. 6
c: an example of a representation of the image of FIG. 6a with emphasized image portions according to an embodiment of the present invention, where the middle region is in focus; and
FIG. 6
d: an example of a representation of the image of FIG. 6a with emphasized image portions according to an embodiment of the present invention, where the background region is in focus.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 depicts a flowchart 100 of an exemplary embodiment of a method for emphasizing specific image portions in an image according to the present invention. The steps 101 to 105 of flowchart 100 may for instance be performed by processor 201 (see FIG. 2) or processor 304 (see FIG. 3). In this exemplary example, it is assumed that all blurred image portions in the image are considered as the specific image portions.
In a first step 101, image data is received, wherein said image data represents an image. In a second step 102, all blurred image portions in said image are identified. Alternatively, also all sharp image portions in said image, or both sharp and blurred image portions could be identified. Said identifying may for instance be performed as described with reference to flowchart 400 in FIG. 4 below. In a step 103, a black-and-white presentation mode is assigned to the identified blurred image portions. In a step 104, the image data is then modified to contain said blurred image portions in black-and-white. In a step 105, the modified image data then is output, so that it may be displayed or further processed.
FIG. 2 shows a block diagram of an exemplary embodiment of an apparatus 200 according to the present invention. Apparatus 200 may for instance be a digital camera, or a device that is equipped with a digital camera, such as for instance a mobile phone. Apparatus 200 comprises a processor 201, which may act as a central processor for controlling the overall operation of apparatus 200. Equally well, processor 201 may be dedicated to operations related to taking, processing and storing of images, for instance in a device that, among other components such as a mobile phone module and an audio player module, is also equipped with a digital camera.
Processor 201 interacts with an input interface 202, via which image data from an image sensor 203 can be received. Image sensor 203, via optical unit 204, is capable of creating image data that represents an image. Image sensor 203 may for instance be embodied as CCD or CMOS sensor. Image data received by processor 201 via input interface 202 may be both analog and digital image data, and may be compressed or uncompressed.
Processor 201 is further configured to interact with an output interface 209 for outputting image data to a display unit 210 for displaying the image that is represented by the image data. Processor 201 is further configured to interact with an image memory 208 for storing images, and with a user interface 205, which may for instance be embodied as one or more buttons (e.g. a trigger of a camera), switches, a keyboard, a touch-screen or similar interaction devices.
Processor 201 is further capable of reading program code from program code memory 206, wherein said program code may for instance contain instructions operable to cause processor 201 to perform the method steps of the flowchart 100 of FIG. 1. Said program code memory 206 may for instance be embodied as Random Access Memory (RAM), or a Read-Only Memory (ROM). Equally well, said program code memory 206 may be embodied as memory that is separable from apparatus 200, such as for instance as a memory card or memory stick. Furthermore, processor 201 is capable of reading a sharpness threshold value from sharpness threshold memory 207.
When a user of apparatus 200 wants to take a picture, he may use user interface 205 to signal to processor 201 that a picture shall be taken. In response, processor 201 then may perform the steps of flowchart 100 of FIG. 1 to emphasize image portions, i.e. receiving image data from image sensor 203 via input interface 202, identifying all blurred image portions in the image that is represented by the image data, assigning a black-and-white presentation mode to the blurred image portions, modifying the image data to contain said blurred image portions in black-and-white, and outputting said modified image data to display unit 210 via output interface 209 (the control of optical unit 204 and image sensor 203, which may be exerted by processor 201, is not discussed here in further detail). Alternatively, said modified image data may be output to an external device for further processing as well.
Therein, to identify all blurred image portions in the image, processor 201 may perform the steps of flowchart 400 of FIG. 4, as will be discussed in further detail below.
Since display unit 210 receives modified image data, i.e. image data in which all blurred image portions are presented in black-and-white, whereas all sharp image portions are presented in color, it is particularly easy for the user to determine if the objects that are to be photographed are in adequate focus or not. The user simply has to inspect if all desired objects are presented in color or not. Examples for this presentation of image data will be given with respect to FIGS. 5a-5c and 6a-6d below. If the desired targets are not in focus, the user may simply change the camera parameters (lens aperture, zoom, line of vision) and check the result on display unit 210.
So far, it was exemplarily assumed that, when a photograph is to be taken, processor 201 automatically performs the steps of flowchart 100 (see FIG. 1) for emphasizing specific image portions. Alternatively, the steps of flowchart 100 may only be taken upon user request, for instance when the user presses a focusing button (i.e. the trigger of a camera) or performs a similar operation. As a further alternative, processor 201 may only perform steps for emphasizing image portions after an image has been captured. Said image data may then for instance be received from image memory 208. Even then, presenting the blurred image portions in black-and-white is advantageous, since the user then can determine if all desired objects are sharp enough or if the picture should be taken anew.
FIG. 3 shows a block diagram of a further exemplary embodiment of an apparatus 300 according to the present invention. Therein, components of apparatus 300 that correspond to components of apparatus 200 (see FIG. 2) have been assigned the same reference numerals and are not explained any further.
Apparatus 300 differs from apparatus 200 in that apparatus 300 comprises a module 303, which is configured to emphasize image portions in an image. To this end, module 303 is furnished with an own processor 304, input and output interfaces 305 and 308, a program code memory 306 and a sharpness threshold memory 307.
In apparatus 300, when a picture is to be taken, image data is received from processor 301 via input interface 202 from image sensor 203, and would, without the presence of module 303, simply be fed into display unit 210 via output interface 209 for displaying. Therein, processor 301 is not configured to emphasize image portions, its functionality may in particular be limited to controlling the process of taking and storing pictures.
By slicing in module 303 into the path between output interface 209 and display unit 210, it can be achieved that image portions in images that are displayed on display unit 210 are emphasized, possibly without affecting the operation of processor 301 and the overall process of taking and storing pictures.
To this end, processor 304 of module 303 may perform the steps of flowchart 100 of FIG. 1, i.e. to receive image data via input interface 305 from output interface 209, to identify all blurred image portions in the image that is represented by the image data, to assign the black-and-white presentation mode to the blurred image portions, to modify the image data so that the blurred image portions are in black-and-white, and to output the modified image data to display unit 210 via output interface 308.
Therein, to identify all blurred image portions in the image, processor 304 of module 303 may perform the methods steps of flowchart 400 (see FIG. 4).
FIG. 4 depicts a flowchart 400 of an exemplary embodiment of a method for identifying specific image portions in an image according to the present invention. This method may for instance be performed by processor 201 (see FIG. 2) and processor 304 (see FIG. 3). In a first step 401, a sharpness threshold value is read, for instance from sharpness threshold memory 207 of apparatus 200 (see FIG. 2) or sharpness threshold memory 307 of apparatus 300 (see FIG. 3). Said sharpness threshold value may for instance be defined by a user via user interface 205 (FIG. 2) and then written into sharpness threshold memory 207. Alternatively, said sharpness threshold value may be a pre-defined value that is stored in said memory during manufacturing. Said sharpness threshold value may for instance depend on the perception capabilities of the human eye and/or the display capabilities of display unit 210 or another display unit. An example for the sharpness threshold value may for instance be a Modulation Transfer Function (MTF) value of 20%.
In a step 402, the image in which blurred image portions are to be identified is divided into N image portions, for instance into quadratic or rectangular image areas. In a loop, which is controlled by steps 403, 404 and 409, for each of these N image portions, a contrast value, for instance in terms of the MTF, is determined (step 405). If the contrast value is larger than the sharpness threshold value, the corresponding image portion is considered as a sharp image portion (step 407), or otherwise as blurred image portion (step 408). In this way, all sharp and all blurred image portions are identified.
FIG. 5
a is an exemplary image 500 in which image portions are exemplarily to be emphasized according to the present invention. Image 500 contains a butterfly 501 residing on a leaf 502. In this macro photography example, butterfly 501 is located in the foreground of image 500, and leaf 502 is located in the background, so that, despite of the comparably small distance between butterfly 501 and leaf 502, one of both easily becomes de-focused and thus blurred.
FIG. 5
b depicts an example of a representation 503 of image 500 of FIG. 5a with emphasized image portions according to an embodiment of the present invention. Representation 503 may for instance be displayed on display unit 210 (see FIGS. 2 and 3) when image 500 is to be taken as a picture by apparatus 200 (FIG. 2) or 300 (FIG. 3). In representation 503, leaf 502 is blurred, and it thus assigned a black-and-white presentation mode. In FIG. 5b, this is illustrated by a hatching. In representation 503, thus butterfly 501 appears in color, since it is in focus (sharp), whereas leaf 502 appears in black-and-white, since it is out-of-focus (blurred). In this way, butterfly 501, i.e. the object which is in focus, is emphasized.
FIG. 5
c depicts a further example of a representation 504 of image 500 of FIG. 5a with emphasized image portions according to an embodiment of the present invention. Therein, now leaf 502 is in focus, and butterfly 502 is out-of-focus, so that butterfly 501 is presented in a specific presentation mode (a black-and-white presentation mode, illustrated by a hatching).
As a further example, not being directed to macro photography, FIG. 6a shows a further exemplary image 600 in which image portions are to be emphasized according to the present invention. Image 600 contains a scene of a volleyball game, wherein players 601-606, a net 607 and a ball 608 are visible. These components of image 600 are located in different layers and are thus impossible to be in focus at the same time.
FIG. 6
b depicts an example of a representation 609 of image 600 of FIG. 6a with emphasized image portions according to an embodiment of the present invention. Therein, players 601 and 602 and ball 608, which are in a foreground layer of image 600, are in focus. This causes all other components of image 600 to be out-of-focus (blurred), and these components thus are assigned a specific (black-and-white) presentation mode. When desiring to focus players 601 and 602 and ball 608, it is thus easy for a user to check the representation 609 to determine if (at least) these components are in color. Otherwise, a new focusing attempt or an additional taking of a picture is required.
FIG. 6
c depicts a further representation 610 of image 600 of FIG. 6a, in which players 603 and 604 in a middle layer of image 600 are in focus, so that all other components are presented in black-and-white (as indicated by the hatching of these components).
Finally, FIG. 6d depicts a representation 611 of image 600 of FIG. 6a, in which players 605 and 606 in a background layer of image 600 are in focus, and all other components of image 600 located in layers before are presented in black-and-white (as indicated by the hatching of these components).
It is thus readily clear that checking if a target or group of targets is in focus when focusing or capturing an image is vastly simplified by the above-described embodiments of the present invention.
The invention has been described above by means of exemplary embodiments. It should be noted that there are alternative ways and variations which are obvious to a skilled person in the art and can be implemented without deviating from the scope and spirit of the appended claims. In particular, it is to be understood that, instead of presenting blurred image areas in black-and-white, equally well other presentation modes may be applied, for instance fading out blurred image portions, applying a colored half-transparent mask to blurred image portions, or similar presentation modes. It is also to be understood that, instead or in addition to the specific presentation of blurred image portions, also the sharp image portions could be presented in an alternative specific presentation mode.
Patent Application
20080084584
