Method and apparatus for improving dynamic range of image

• US 8,456,555 B2
• Filed: 11/16/2007
• Issued: 06/04/2013
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Um, Kyu-hoi, Lee, Sang-jin, Im, Na-ri
• Primary Examiner(s): Fan, Chieh M
• Assistant Examiner(s): Trehan, Akshay
• Application Number:
  US11/941,202
• Publication Number:
  US 20090002525A1
• Time in Patent Office: 2,027 Days
• Field of Search: 348/241, 348/240.2, 348/276, 348/221.1, 348/297, 348/362, 358/48, 257/432
• US Class Current: 348/297
• CPC Class Codes: H04N 23/72 Combination of two or more compensation controls
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions

Abstract

Provided are a method and apparatus for improving a dynamic range of an image. The method of improving a dynamic range of an image, which is obtained by a sensor unit of an image capture device, includes: creating an input image by using the sensor unit which has a plurality of lines and has different integration times for the individual lines; and creating an interpolated image by performing interpolation filtering on the input image by using neighboring lines of a current line which have different integration times.

Claims

1. A method of improving a dynamic range of an image which is obtained by a sensor unit of an image capture device, the method comprising:

obtaining a single initial image using the sensor unit;

analyzing a plurality of separate dynamic ranges for a plurality of lines of the single initial image;

setting integration times for the plurality of lines of the sensor unit to achieve different dynamic ranges for neighboring lines of the plurality of lines by using the analyzed dynamic ranges for the plurality of lines of the initial image; and

creating an input image using the sensor unit which has the integration times set for the plurality of lines, wherein an individual line of the plurality of lines has a different integration time controlled individually from integration times of neighboring lines of the individual line to achieve the different dynamic ranges for the individual line and the neighboring lines; and

creating an interpolated image by performing interpolation filtering on the input image by using neighboring lines of a current line of the plurality of lines which have different integration times from an integration time of the current line,

wherein a line of the plurality of lines consists of a row of a plurality of pixels which have a same integration time with each other.

2. The method of claim 1, wherein in the creating the input image, the integration times of the sensor unit are previously determined for the plurality of lines.

3. The method of claim 1, wherein the creating the interpolated image comprises:

calculating a correlation between the current line and the neighboring lines; and

controlling filter coefficients of the interpolation filtering based on the correlation.

4. The method of claim 3, wherein the interpolation filtering is used to calculate weighted summation which is obtained by multiplying a pixel value of a pixel in the current line by a certain weight and multiplying at least one of pixel value of pixels in each of the neighboring lines by another weight and adding the multiplied pixel values together.

5. The method of claim 3, wherein the filter coefficients are determined based on the integration times for the plurality of lines.

6. The method of claim 3, wherein the filter coefficients are determined based on a dynamic range of the input image.

7. The method of claim 1, wherein in the setting the integration times, the integration times for the plurality of lines are individually controlled based on a dynamic range of the initial image.

8. The method of claim 1, wherein in the setting the integration times, the integration times for the plurality of lines are individually controlled based on a noise level of the initial image.

9. The method of claim 1, wherein in the setting the integration times, the integration times for the plurality of lines are individually controlled based on an amount of movement blurring that occurs if there is movement in the initial image.

10. An apparatus for improving an image dynamic range of an image capture device, the apparatus comprising:

a sensor unit which obtains a single initial image by converting incident light into electronic signals;

an integration time controlling unit which analyzes a plurality of separate dynamic ranges for a plurality of lines of the single initial image, individually controls integration times for the plurality of lines of the sensor unit to achieve different dynamic ranges for neighboring lines of the plurality of lines using the analyzed dynamic ranges for the plurality of lines of the initial image obtained by the sensor unit, wherein an individual line of the plurality of lines has a different integration time controlled individually from integration times of neighboring lines of the individual line to achieve the different dynamic ranges for the individual line and the neighboring lines, and the sensor creates an input image by using the controlled integration times; and

an image processing unit which performs interpolation filtering on the input image, by using a current line of the plurality of lines and neighboring lines of the current line which have different integration times from an integration time of the current line, and creates an interpolated image,

wherein a line of the individual lines consists of a row of a plurality of pixels which have a same integration time with each other.

11. The apparatus of claim 10, wherein the image processing unit comprises:

a correlation calculation unit which calculates correlation between the current line and the neighboring lines;

an interpolation filter creating unit which controls interpolation filter coefficients of the interpolation filtering based on the correlation; and

an interpolation filtering unit which performs the interpolation filtering using the interpolation filter.

12. The apparatus of claim 11, wherein the interpolation filtering is used to calculate weighted summation which is obtained by multiplying a pixel value of a pixel in the current line and at least one of pixel value of pixels in each of the neighboring lines by a certain weight and adding the multiplied pixel together.

13. The apparatus of claim 11, wherein the interpolation filter creating unit determines the interpolation filter coefficients based on the integration times for the plurality of lines.

14. The apparatus of claim 11, wherein the interpolation filter creating unit determines the interpolation filter coefficients based on a dynamic range of the input image.

15. The apparatus of claim 10, wherein the integration time controlling unit controls and sets at least one of the integration times for the plurality of lines differently based on a dynamic range of the initial image.

16. The apparatus of claim 10, wherein the integration time controlling unit controls and sets at least one of the integration times for the plurality of lines differently based on a noise level of the initial image.

17. The apparatus of claim 10, wherein the integration time controlling unit controls and sets at least one of the integration times for the plurality of lines differently based on an amount of movement blurring that occurs when there is movement in the initial image.

18. The apparatus of claim 10, wherein the image processing unit controls and sets at least one of the integration times for the plurality of lines differently based on a dynamic range of the initial image.

19. The apparatus of claim 10, wherein the image processing unit controls and sets at least one of the integration times for the plurality of lines differently based on a noise level of the initial image.

20. The apparatus of claim 10, wherein the image processing unit controls and sets at least one of the integration times of the plurality of lines differently based on an amount of movement blurring that occurs if there is movement in the initial image.

21. A non-transitory computer readable recording medium having embodied thereon a computer program for executing a method of improving a dynamic range of an image which is obtained by a sensor unit of an image capture device, the method comprising:

obtaining a single initial image using the sensor unit;

analyzing a plurality of separate dynamic ranges for a plurality of lines of the single initial image;

setting integration times for the plurality of lines of the sensor unit to achieve different dynamic ranges for neighboring lines of the plurality of lines by using the analyzed dynamic ranges for the plurality of lines of the initial image; and

creating an input image using the sensor unit which has the integration times set for the plurality of lines, wherein an individual line of the plurality of lines has a different integration time controlled individually from integration times of neighboring lines of the individual line to achieve the different dynamic ranges for the individual line and the neighboring lines; and

creating an interpolated image by performing interpolation filtering on the input image by using neighboring lines of a current line of the plurality of lines which have different integration times from an integration time of the current line,

wherein a line of the plurality of lines consists of a row of a plurality of pixels which have a same integration time with each other.

22. An apparatus for improving an image dynamic range of an image capture device, the apparatus comprising:

a sensor unit which obtains a single initial image by converting incident light into electronic signals;

an integration time controlling unit which individually controls integration times for a plurality of lines of the sensor unit, wherein an individual line of the plurality of lines has a different integration time controlled individually from integration times of neighboring lines of the individual line to achieve different dynamic ranges for the individual line and the neighboring lines, and the sensor creates an input image by using the controlled integration times; and

an image processing unit which analyzes a plurality of separate dynamic ranges for the plurality of lines of the single initial image and determines the integration times for the plurality of lines to achieve different dynamic ranges for neighboring lines of the plurality of lines by using the analyzed dynamic ranges for the plurality of lines of the initial image, performs interpolation filtering on the input image, by using a current line of the plurality of lines and neighboring lines of the current line which have different integration times from an integration time of the current line, and creates an interpolated image,

wherein the integration time controlling unit individually controls the integration times of the plurality of lines based on the integration times determined by the image processing unit, and

wherein a line of the individual lines consists of a row of a plurality of pixels which have a same integration time with each other.