System and method for image segmentation

• US 7,298,898 B2
• Filed: 04/15/2003
• Issued: 11/20/2007
• Est. Priority Date: 04/15/2003
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Prado, Edward R., Haque, Jamal, Wilcox, Michelle S., Prewitt, John P., Parker, James D.
• Primary Examiner(s): Do; Anh Hong
• Application Number:
  US10/413,378
• Publication Number:
  US 20040208364A1
• Time in Patent Office: 1,680 Days
• Field of Search: 382/260, 382/168, 382/171, 382/172, 382/266, 382/101, 382/302, 382/104, 382/103, 382/173, 600/454, 600/455, 340/937, 348/149
• US Class Current: 382/173
• CPC Class Codes: G06T 2200/28 involving image processing hardware
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: G06T 7/194 involving foreground-background segmentation

Abstract

An image segmentation apparatus, preferably integrally implemented in a device such as an FPGA, including a buffer memory for storing pixel data, a digital filter in communication with the buffer memory, the digital filter having programmable coefficients, a histogram generating module in communication with the buffer memory that generates a histogram of the pixel data, a statistics generating module in communication with the buffer memory that generates statistics regarding the pixel data, a threshold select module for selecting one of a plurality thresholds and an apply threshold module for applying the selected threshold to data stored in the buffer to generate exceedance data that exceed the selected threshold. In a preferred embodiment, a control module controls each of the buffer, histogram, statistics and threshold modules to control data flow, program filter coefficients and select the appropriate threshold.

Claims

1. A digital signal processing apparatus, comprising:

a buffer memory operable to store pixel data;

a histogram generating module in communication with the buffer memory, the histogram generating module operable to generate a histogram of the pixel data;

a statistics generating module in communication with the buffer memory, the statistics generating module operable to generate statistics regarding the pixel data;

a threshold select module for selecting one of a plurality of thresholds and an apply threshold module for applying the selected threshold to data stored in the buffer; and

a control module for controlling each of the buffer, histogram, statistics and threshold modules by updating registers in at least one of the buffer, histogram, statistics and threshold modules to cause a re-flow of the data through at least one of the buffer, histogram, statistics and threshold modules, wherein a portion of the data is passed through at least one of the buffer, histogram, statistics and threshold modules at least twice based on the statistics generated for the portion of the re-flowed data, wherein a histogram and exceedance data that exceed the selected threshold are provided to a downstream general purpose processor.

2. The apparatus of claim 1, further comprising a filter.

3. The apparatus of claim 2, wherein the filter is a spatial filter.

4. The apparatus of claim 2, wherein the filter comprises programmable coefficients.

5. The apparatus of claim 2, wherein the filter is operable to be at least one of a smoothing filter and an edge detecting filter.

6. The apparatus of claim 1, wherein the histogram is comprised of 1024 bins.

7. The apparatus of claim 1, wherein the statistics generating module is operable to calculate at least a mean and standard deviation.

8. The apparatus of claim 1, wherein the selected threshold is settable by the general purpose processor.

9. The apparatus of claim 1, wherein the selected threshold is based on the generated statistics.

10. The apparatus of claim 1, wherein two sets of exceedance data are provided to the downstream general purpose processor.

11. The apparatus of claim 10, wherein a difference between a first set and a second set of exceedance data is based on an application of an offset value associated with the threshold.

12. An image segmentation apparatus, comprising:

a buffer memory operable to store pixel data;

a digital filter in communication with the buffer memory;

a histogram generating module in communication with the buffer memory, the histogram generating module operable to generate a histogram of the pixel data;

a statistics generating module in communication with the buffer memory, the statistics generating module operable to generate statistics regarding the pixel data;

a threshold select module for selecting one of a plurality of thresholds and an apply threshold module for applying the selected threshold to data stored in the buffer; and

a control module for controlling each of the buffer, histogram, statistics and threshold modules by updating registers in at least one of the buffer, histogram, statistics and threshold modules to cause a re-flow of the data through at least one of the buffer, histogram, statistics and threshold modules, wherein a portion of the data is passed through at least one of the buffer, histogram, statistics and threshold modules at least twice based on the statistics generated for the portion of the re-flowed data,

wherein a histogram and exceedance data that exceed the selected threshold are provided to a downstream general purpose processor.

13. The apparatus of claim 12, wherein the filter is a spatial filter.

14. The apparatus of claim 12, wherein the filter has programmable coefficients.

15. The apparatus of claim 12, wherein the filter is operable to be at least one of a smoothing filter and an edge detecting filter.

16. The apparatus of claim 12, wherein the histogram is comprised of 1024 bins.

17. The apparatus of claim 12, wherein the statistics generating module is operable to calculate at least a mean and standard deviation.

18. The apparatus of claim 12, wherein the selected threshold is settable by the general purpose processor.

19. The apparatus of claim 12, wherein the selected threshold is based on the generated statistics.

20. The apparatus of claim 12, wherein the two set of exceedance data are provided to the downstream general purpose processor.

21. The apparatus of claim 20, wherein a difference between a first set and a second set of exceedance data is based on an application of an offset value associated with the threshold.

22. A method of performing image segmentation, comprising:

storing pixel data;

controlling and setting programmable filter coefficients and digitally filtering the data at least one time;

generating a histogram of the data;

generating statistics based on the data;

selecting one of a plurality of thresholds, at least one of the plurality of thresholds being calculated based on the statistics;

applying a selected threshold to the data;

outputting the histogram; and

outputting exceedance data that exceed the selected threshold, the exceedance data representing, at least partially, an image segmented from the pixel data, wherein controlling and setting programmable filter coefficients and digitally filtering the data at least one time comprises;

resetting the programmable filter coefficients based on the statistics;

re-inputting the data back to a filter; and

filtering the re-input data with the reset programmable filter coefficients.

23. The method of claim 22, further comprising modifying the threshold level on a per pixel frame basis.

24. The method of claim 22, further comprising calculating exceedance data based on an offset value added to the selected threshold.

25. The method of claim 24, wherein two sets of exceedance data are output.

26. The method of claim 22, further comprising receiving instructions from a general purpose processor.

27. The method of claim 22, wherein the number of coefficients is 25 for a filter having a 5×

5 pixel mask.