Apparatus and method for processing images
View Patent ↗An apparatus for processing images includes an image sensor to output a long exposure image frame based upon a first exposure time and at least two short exposure image frames having a single, second exposure time different from the first exposure time; a mode determination unit to determine the second exposure time based on the number of saturated pixels in the image frame output from the image sensor; a shutter controller to control the exposure time of each frame of the image sensor based on an output signal from the mode detection unit; and an image processing unit to fuse the long exposure image frame and the at least two short exposure image frames to output a wide dynamic range (WDR) image. Methods for processing WDR images are also disclosed.
1. An apparatus for processing images comprising:
an image sensor to output a long exposure image frame based upon a first exposure time and at least two short exposure image frames having a single, second exposure time different from the first exposure time;
a first processor to determine the second exposure time based on a number of saturated pixels in the long exposure image frame or one of the at least two short exposure image frames output from the image sensor;
a shutter controller to control the exposure time of each frame of the image sensor based on an output signal from the first processor; and
an image processor to fuse the long exposure image frame and the at least two short exposure image frames to output a wide dynamic range (WDR) image.
2. The apparatus of claim 1 , wherein the image processor comprises:
a motion detector to compare a predetermined region of the image frame in the long exposure image frame and each of the at least two short exposure image frames, and detect a change in motion of an object in the image frames;
a frame selector to select either the long exposure image frame or the short exposure image frame based upon which image frame has least an amount of change in motion of the object in the predetermined region of the image frame; and
a fusing controller to fuse all of the selected image frame regions and output a wide dynamic range (WDR) image.
3. The apparatus of claim 2 , wherein the frame selector selects the predetermined region of the long image frame if pixels in a predetermined region of the long image frame are not saturated.
4. The apparatus of claim 2 , wherein the frame selector selects the predetermined region of the short exposure image frame based upon which image frame has the least amount of change in motion of the object in the predetermined region of the each short image frame if pixels in the predetermined region of the long image frame are saturated.
5. The apparatus of claim 1 , wherein the first processor comprises:
a saturated pixels counter to receive a signal corresponding to a predetermined image frame output from the image sensor, and to count the number of saturated pixels included in the predetermined image frame;
a comparator to compare the number of saturated pixels with a predetermined reference value; and
a mode decision controller to determine an operation mode of the image processing unit based on an output from the comparator.
6. The apparatus of claim 5 , wherein the operation mode includes a first operation mode which is employed when the number of saturated pixels is larger than the reference value and a second operation mode which is employed when the number of saturated pixels is smaller than the predetermined reference value.
7. The apparatus of claim 6 , wherein, in the second operation mode, the image processor receives a long exposure image frame based upon a first exposure time and three short exposure image frames having a second exposure time smaller than the first exposure time.
8. The apparatus of claim 1 , wherein the second exposure time is smaller than the first exposure time.
9. An apparatus for processing image comprising:
an image sensor to output a long exposure image frame based upon a first exposure time and at least two short exposure image frames having a single, second exposure time different from the first exposure time;
a motion detector to compare a predetermined region of the image frame in the long exposure image frame and each of the at least two short exposure image frames, and to detect a change in motion of an object in the image frames;
a frame selector to select either the long exposure image frame or the short exposure image frame based upon which image frame has least an amount of change in motion of the object in the predetermined region of the image frame; and
a fusing controller to fuse all of the selected image frame regions and output a wide dynamic range (WDR) image.
10. The apparatus of claim 9 , wherein the frame selector selects the predetermined region of the long image frame if pixels in a predetermined region of the long image frame are not saturated.
11. The apparatus of claim 9 , wherein the frame selector selects the predetermined region of the short exposure image frame based upon which image frame has least the amount of change in motion of the object in the predetermined region of the each short image frame if pixels in a predetermined region of the long image frame are saturated.
12. The apparatus of claim 9 , wherein the at least two short exposure image frames comprises three short exposure image frames.
13. The apparatus of claim 9 , wherein the second exposure time is smaller than the first exposure time.
14. A method for processing images comprising the steps of:
receiving a signal corresponding to a predetermined image frame;
counting a number of saturated pixels included in the predetermined image frame;
comparing the number of saturated pixels with a predetermined reference value;
outputting a long exposure image frame based upon a first exposure time and at least two short exposure image frames having a single, second exposure time different from the first exposure time, when the number of pixels saturated is smaller than the predetermined reference value;
comparing a predetermined region of the image frame in the long exposure image frame and each of the at least two short exposure image frames, and detecting a change in motion of an object in the image frames;
selecting either the long exposure image frame or the short exposure image frame based upon which image frame has least an amount of change in motion of the object in the predetermined region of the image frame; and
fusing all of the selected image frame regions and outputting a wide dynamic range (WDR) image.
15. The method of claim 14 , wherein the step of selecting either the long exposure image frame or the short exposure image frame comprises:
selecting the predetermined region of the long image frame if pixels in the predetermined region of the long image frame are not saturated.
16. The method of claim 14 , wherein the step of selecting either the long exposure image frame or the short exposure image frame comprises:
selecting the predetermined region of the short exposure image frame based upon which image frame has least the amount of change in motion of the object in the predetermined region of each of the short image frames if the pixels in the predetermined region of the long image frame are saturated.
17. The method of claim 14 , wherein the at least two short exposure image frames comprises three short exposure image frames.
18. The apparatus of claim 14 , wherein the second exposure time is smaller than the first exposure time.
19. The apparatus of claim 14 , further comprising the step of outputting the long exposure image frame based upon the first exposure time and the at least two short exposure image frames having at least two second exposure times different from the first exposure time, when the number of pixels saturated is larger than the predetermined reference value.
20. The apparatus of claim 19 , wherein the at least two short exposure image frames comprises three short exposure image frames having three different second exposure times smaller than the first exposure time.