Image photographing apparatus for providing out-of-focus effect and method of controlling thereof
An image photographing apparatus is provided, which includes a camera which photographs an image, a processor which is configured to control the camera to acquire a plurality of first images based on a first shutter timing and to acquire a second image based on a second shutter timing, wherein the processor is further configured to generate a brightness map of the second image using the acquired first images, and to generate a post-processed image of the second image using the generated brightness map.
1. An image photographing apparatus, comprising:
a camera; and
a processor configured to:
control the camera to acquire a plurality of first images based on a first shutter timing and to acquire a second image based on a second shutter timing;
composite the plurality of first images one by one for accumulating brightness information included in each of the plurality of first images;
obtain a brightness map based on the accumulated brightness information; and
obtain a post-processed image of the second image using the obtained brightness map.
2. The image photographing apparatus of claim 1 , wherein the processor is configured to identify a saturation state of coordinate values of a composite image while the plurality of first images is being composited, obtain brightness information of the coordinate values based on a number of the first images in which the coordinate values include a saturation state, and obtain the brightness map based on the acquired brightness information of the coordinate values.
3. The image photographing apparatus of claim 2 , wherein the processor is configured to stop compositing the plurality of first images when a brightness of the coordinate values of a composite image corresponding to a main subject included in the second image reaches a preset value.
4. The image photographing apparatus of claim 2 , wherein the processor is configured to adjust a resolution of the plurality of first images, and composite the resolution-adjusted first images.
5. The image photographing apparatus of claim 1 , wherein the processor is configured to obtain a depth map of the second image; obtain information on per-depth image coordinate sets of the second image, and information on per-depth Bokeh corresponding to the per-depth image coordinate sets; and post-process the second image by applying the corresponding per-depth Bokeh to each of the per-depth image coordinate sets respectively.
6. The image photographing apparatus of claim 5 , wherein the processor is configured to obtain information on per-depth image coordinate sets of the second image by dividing the second image into coordinates comprising a same depth based on the depth map; obtain size information and shape information of the per-depth Bokeh based on information on a lens parameter set for the image photographing apparatus, the depth map and the per-depth image coordinate sets; and obtain magnitude information of the per-depth Bokeh based on the brightness map.
7. The image photographing apparatus of claim 5 , wherein the processor is configured to identify a size of the per-depth Bokeh satisfying the equation:
Δ
u
=
(
1
F
#
)
(
f
a
)
2
Δ
z
where, ‘Δu’ denotes a Bokeh size, ‘F#’ is F-number of a lens set for the image photographing apparatus, ‘f’ is a focal distance of the lens set for the photographing apparatus, ‘a’ is a distance between main subject of the second image and the lens, and ‘Δz’ is a distance between the main subject of the second image and the object in the background.
8. The image photographing apparatus of claim 7 , wherein the processor is configured to convert the identified size of the per-depth Bokeh based on a size of an image sensor included in the camera.
9. The image photographing apparatus of claim 5 , wherein the processor is configured to perform a convolution operation of the corresponding per-depth Bokeh for each of the per-depth image coordinate sets, combine results of the convolution operations per depth, and perform post-processing of the second image.
10. The image photographing apparatus of claim 1 , further comprising:
an input; and
a display,
wherein the processor is further configured to:
while the post-processed image of the second image is displayed, control the display to display a menu to adjust lens parameter including at least one user interface (UI) element corresponding to at least one lens parameter; and
based on receiving an instruction input to the at least one UI element through the input, re-post-process the second image based on a lens parameter corresponding to the UI element through which the instruction is input, and to control the display to display the re-post-processed second image.
11. A method of controlling an image photographing apparatus, comprising:
acquiring a plurality of first still images based on a first shutter timing and acquiring a second still image based on a second shutter timing;
compositing the plurality of first images one by one for accumulating brightness information included in each of the plurality of first images;
obtaining a brightness map based on the accumulated brightness information; and
obtaining a post-processed image of the second image using the obtained brightness map.
12. The method of claim 11 , wherein obtaining the brightness map comprises:
identifying a saturation state of coordinate values of a composite image while the plurality of first images is being composited;
obtaining brightness information of the coordinate values based on a number of the first images in which the coordinate values include saturation state; and
obtaining the brightness map based on the acquired brightness information of the coordinate values.
13. The method of claim 12 , wherein compositing the plurality of first images comprises stopping compositing the plurality of first images when a brightness of the coordinate values of a composite image corresponding to a main subject included in the second image reaches a preset value.
14. The method of claim 12 , wherein compositing the plurality of first images comprises:
adjusting a resolution of the plurality of first images; and
compositing the resolution-adjusted first images.
15. The method of claim 11 , further comprising obtaining a depth map of the second image, wherein
obtaining the post-processed image comprises:
obtaining information on per-depth image coordinate sets of the second image, and information on per-depth Bokeh corresponding to the per-depth image coordinate sets; and
performing post-processing of the second image by applying the corresponding per-depth Bokeh to each of the per-depth image coordinate sets respectively.
16. The method of claim 15 , wherein generating the information comprises:
obtaining information on per-depth image coordinate sets of the second image by dividing the second image into coordinates comprising a same depth based on the depth map; and
obtaining size information and shape information of the per-depth Bokeh based on information of a lens parameter set for the image photographing apparatus, the depth map and the per-depth image coordinate sets, and obtaining magnitude information of the per-depth Bokeh based on the brightness map.
17. The method of claim 15 , wherein obtaining the information comprises identifying a size of the per-depth Bokeh satisfying the equation:
Δ
u
=
(
1
F
#
)
(
f
a
)
2
Δ
z
where, ‘Δu’ denotes a Bokeh size, ‘F#’ is F-number of a lens set for the image photographing apparatus, ‘f’ is a focal distance of the lens set for the photographing apparatus, ‘a’ is a distance between main subject of the second image and the lens, and ‘Δz’ is a distance between the main subject of the second image and the object in background.
18. The method of claim 17 , wherein obtaining the information comprises converting the identified size of the per-depth Bokeh based on a size of an image sensor included in the photographing apparatus.
19. The method of claim 15 , wherein performing the post-processing comprises:
performing a convolution operation of the corresponding per-depth Bokeh for each of the per-depth image coordinate sets; and
combining results of the convolution operations per depth.
20. The method of claim 11 , further comprising:
displaying a menu to adjust lens parameter while displaying the post-processed image of the second image, the menu including at least one user interface (UI) element corresponding to at least one lens parameter;
based on receiving an instruction input to the at least one UI element, re-post-processing the second image based on a lens parameter corresponding to the UI element through which the instruction is input; and
displaying the re-post-processed second image.