Image stabilizing apparatus using bit-plane matching and image stabilizing method using the same

• US 6,535,244 B1
• Filed: 10/13/1998
• Issued: 03/18/2003
• Est. Priority Date: 10/10/1997
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Gun-hee, Ko, Sung-jea
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): Ye, Lin
• Application Number:
  US09/170,074
• Time in Patent Office: 1,617 Days
• Field of Search: 348/208, 348/699, 348/208.1, 348/208.4
• US Class Current: 348/208.1
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/683 performed by a processor, e.g. controlling the readout of an image memory
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51

Abstract

An image stabilizing apparatus for correcting motion of an image recording apparatus by using a bit-plane matching technique, and an image stabilizing method thereof. In the image stabilizing apparatus, a field memory stores input digital image information. A motion detecting circuit calculates an amount of movement of input image information between two screens by using bit-plane matching technique and outputs a motion vector of the image recording apparatus. A motion correcting circuit corrects the motion of the image recording apparatus by moving image information stored in the field memory in an opposite direction to the direction of the motion vector.

Claims

1. An image stabilizing apparatus of an image recording apparatus comprising:

a memory for storing input digital image information;

a motion detecting circuit for calculating an amount of movement of input image information between two screens by using bit-plane matching technique and generating a motion vector of the input image; and

a motion correcting circuit for receiving the motion vector generated by the motion correction circuit and correcting the movement of the input image information by the moving image information stored in the field memory in an opposite direction to a direction of the motion vector.

2. The image stabilizing apparatus of claim 1, wherein the motion detecting circuit comprises:

a bit-plane extractor for extracting bit-planes from input digital image information;

an optimum bit-plane detector for detecting an optimum bit-plane suitable for detecting motion among the bit-planes extracted by the bit-plane extractor;

a bit-plane memory for storing the optimum bit-plane detected by the bit-plane detector;

a bit-plane correlation value detector for comparing pixel values of the optimum bit-plane of a previous screen stored in the bit-plane memory and pixel values of the optimum bit-plane in a current screen to calculate correlation values between pixels of the bit-planes, and accumulating the calculated correlation values; and

a motion vector calculator for calculating the motion vector from the accumulated correlation value.

3. An image stabilizing method in an image recording apparatus, the method comprises the steps of:

(a) detecting a motion vector of an input image using a bit-plane matching technique; and

(b) correcting motion of an image recording apparatus by moving the input image in an opposite direction to a direction of the detected motion vector.

4. The image stabilizing method of claim 3, wherein the step (a) comprises the steps of:

(a1) extracting bit-planes from digital image information;

(a2) selecting an optimum bit-plane among the extracted bit-planes;

(a3) storing the optimum bit planes of a previous screen and a current screen;

(a4) comparing pixel values of the optimum bit-plane of the previous screen stored in the bit-plane memory and pixel values of the optimum bit-plane in the current screen to calculate correlation values between pixels of the bit-planes, and accumulating the calculated correlation values; and

(a5) calculating a motion vector from the accumulated correlation value.

5. The image stabilizing method of claim 4, wherein the step (a2) comprises the steps of:

(a2a) initializing an optimal bit-plane index m and an average bit conversion rate C_avg;

(a2b) calculating a bit conversion rate C_m of an optimal bit-plane determined by the optimal bit-plane index m;

(a2c) determining whether an absolute value of the difference between the calculated bit conversion rate C_m and the average bit conversion rate C_avg is equal to or less than a predetermined threshold value; and

(a2d) maintaining a current bit-plane if the absolute value is less than or equal to the threshold value, and changing the bit-plane if the absolute value is greater than the threshold value.

6. The image stabilizing method of claim 5, wherein the average bit conversion rate is reset to $C_{\mathrm{avg}}=\frac{C_m+C_{\mathrm{avg}}}{2}$

if the current bit-plane is maintained in the step (a2d).

7. The image stabilizing method of claim 5, wherein the changing of the bit-plane in the step (a2d) comprises the steps of:

determining whether the bit conversion rate C_m is greater than the average bit conversion rate C_avg; and

selecting an upper bit-plane if the bit conversion rate C_m is greater than the average bit conversion rate C_avg, and a lower bit-plane if the bit conversion rate C_m is not greater than the average bit conversion rate C_avg.

8. The image stabilizing method of claim 5, further comprising the step of setting a predetermined number of motion detection regions in the selected optimum bit-plane,

wherein pixel values of the optimum bit-plane of a previous screen are compared with pixel values of the optimum bit-plane in a current screen with respect to pixel values in the predetermined number of motion detection regions.