Moving text detection in video

• US 8,718,366 B2
• Filed: 04/01/2009
• Issued: 05/06/2014
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: ATI Technologies ULC (Advanced Micro Devices, Inc.)
• Original Assignee: ATI Technologies ULC (Advanced Micro Devices, Inc.)
• Inventors: Wredenhagen, Gordon F.
• Primary Examiner(s): BEKELE, MEKONEN T
• Application Number:
  US12/416,347
• Publication Number:
  US 20100254605A1
• Time in Patent Office: 1,861 Days
• Field of Search: 382/176, 382/104, 382/107, 382/159, 382/161, 382/198, 382/218, 382/229, 382/105, 382/199, 382/228, 382/173, 382/69, 382/170, 382/171, 382/205, 382/260, 382/177, 382/202, 340/905, 340/910, 340/936, 340/146.2, 340/305, 348/571, 348/E05.062, 348/468, 348/263, 348/447, 348/451, 348/452, 348/462, 348/450, 348/524, 348/663, 348/668, 348/669, 348/E5.1, 348/449, 348/208.1, 348/700, 348/701, 348/445, 348/550, 348/607, 348/97, 358/3.13, 358/462, 358/1.9
• US Class Current: 382/176
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20044 Skeletonization; Medial axis transform
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06V 20/40 in video content extracting overlay text G06V20/62; video retrieval G06F16/70; processing of video elementary streams in video servers H04N21/234; processing of video elementary streams in video clients H04N21/44
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20

Abstract

Methods and apparatus for detecting moving text in video comprising receiving consecutive frames from a video stream, extracting a sequence of pixels from the consecutive frames, categorizing the pixels, thinning the pixels, correlating corresponding thinned pixels in the frames, identifying the peaks that are equal to or exceed a threshold, and performing further processing on the peaks to determine if the peaks contain moving text.

Claims

1. A method for detecting moving text in video comprising:

extracting consecutive frames from a video stream;

extracting rows of pixels from the consecutive frames;

extracting pixel values from the pixels; and

identifying peak candidates derived from the pixels that equal or exceed a threshold.

2. The method of claim 1 further comprising:

categorizing the pixels based on the extracted pixel values;

thinning the categorized pixels;

converting thinned categorized pixels; and

cross correlating corresponding thinned pixels from consecutive frames.

3. The method of claim 2 wherein the cross correlating is a phase plane correlation.

4. The method of claim 2 wherein the categorizing comprises:

subtracting a first pixel value from a second pixel value and obtaining a result; and

comparing the result to at least one threshold.

5. The method of claim 2 wherein thinning comprises determining a first instance of similarly categorized pixels.

6. A moving text detection device comprising:

an extractor configured to extract from consecutive frames in a video stream rows of pixels;

wherein consecutive frames occur in the video stream following one after the other in continuous sequence; and

a processor configured to categorize pixels;

a thinning module configured to thin the categorized pixels; and

a correlator configured to perform correlation of the thinned pixels.

7. The moving text detection device of claim 6 further comprising:

a receiver configured to receive a video stream.

8. The moving text detection device of 6 further comprising:

a state machine configured to perform thinning or extraction.

9. The moving text detection device of 6 wherein the correlator is a phase plane correlator.

10. A moving text detection device comprising:

an extractor configured to extract consecutive frames from a video stream;

wherein consecutive frames occur in the video stream following one after the other in continuous sequence;

the extractor further configured to extract rows of pixels from the consecutive frames;

the extractor further configured to extract pixel values from the pixels; and

a processor configured to identify peak candidates from pixels that equal or exceed a threshold.

11. The moving text detection device of claim 10 further comprising:

the processor further configured to categorize the pixels based on the extracted pixel values;

a thinning module configured to thin the categorized pixels;

the processor further configured to convert the thinned categorized pixels; and

a correlator configured to cross correlate corresponding thinned pixels from consecutive frames.

12. The moving text detection device of 11 wherein the correlator is a phase plane correlator.

13. The moving text detection device of 10 wherein the processor is further configured to:

subtract a first pixel value from a second pixel value and obtaining a result; and

comparing the result to at least one threshold.

14. The moving text detection device of 11 wherein the thinning module is further configured to determine a first instance of similarly categorized pixels.

15. A non-transitory computer readable storage medium comprising:

a first set of instructions adapted to provide a processor, wherein the processor is configured to implement a second set of instructions, the second set of instructions comprising;

an extraction code segment for extracting at least one row of pixels from consecutive frames;

wherein consecutive frames follow one after the other in continuous sequence in the video stream; and

an identification code segment for identifying peak candidates derived from pixels that equal or exceed a threshold.

16. The non-transitory computer readable storage medium of claim 15 wherein the second set of instructions further comprises:

a receiving code segment for receiving consecutive frames from a video stream.

17. The non-transitory computer readable storage medium of claim 15 wherein the second set of instructions further comprises:

a categorization code segment for categorizing the pixels;

a thinning code segment for thinning the categorized pixels; and

a correlation code segment for correlating corresponding thinned pixels in the frames.

18. The non-transitory computer readable medium of claim 15 wherein the first set of instructions or the second set of instructions are hardware description language (HDL) instructions.