Morphology processing apparatus and method

• US 6,233,369 B1
• Filed: 01/20/1999
• Issued: 05/15/2001
• Est. Priority Date: 10/17/1997
• Status: Expired due to Term

• Current Assignee: Microscan Systems Inc (Omron Corporation)
• Original Assignee: Acuity Brands, Inc.
• Inventors: Wilt, Michael J.
• Primary Examiner(s): Au, Amelia M.
• Assistant Examiner(s): Wu, Jingge
• Application Number:
  US09/234,396
• Time in Patent Office: 846 Days
• Field of Search: 382/302, 382/303, 382/304, 382/307, 382/308, 382/205
• US Class Current: 382/308
• CPC Class Codes: G06F 13/4027 using bus bridges G06F13/4022 takes precedence
• CPC Class Codes: G06T 1/60 Memory management
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor

Abstract

The present invention provides a novel system and method that permits a “mask” to be directly incorporated into an image during image processing. This is accomplished by processing binary images or image data which are encoded using two bits rather than the usual one. The second bit is defined to be a “mask enable”, which directs a processor to pass the original data through to the output image regardless of the processing result for that pixel. The present invention also provides a means of automatically providing background data to the processor for pixels outside the original image so that the result image is always the same size as the original image. For binary images, the background may be defined to have a value of “0” or “1”, and this value is provided to the processing engine in place of all of the pixels which lie outside the original image. For gray-scale images, the minimum or maximum possible value is provided to the processing engine in place of all of the pixels which lie outside of the original image, effectively eliminating these values from consideration when the minimum or maximum of the neighborhood pixels is computed. The determination of whether a pixel is outside of the original image is implemented using the framing signals provided by a data flow controller along with the image data.

Claims

1. A system for performing morphology computations on image pixel data, comprising:

a data flow controller, for providing image pixel data in groups containing at least two adjacent image pixel data values, and for providing framing signals;

a neighborhood generator, for receiving said image pixel data and framing signals and for generating at least two sets of neighborhood data, each of said two sets of neighborhood data containing at least three rows and at least four columns of said image pixel data and at least one corresponding pixel-valid signal for each image pixel data value in said at least three rows and at least four columns of said image pixel data in each said at least two sets of neighborhood data;

at least one validity checker, responsive to said pixel-valid signal for each image pixel data value in said at least three rows and at least four columns of said image pixel data in each said at least two sets of neighborhood data, for substituting background values in place of said image pixel data values when said pixel-valid signal corresponding to said image pixel value is false; and

at least two neighborhood processors, responsive to said at least two sets of neighborhood data and said pixel-valid signal for each image pixel data value in said at least three rows and at least four columns of said image pixel data in each said at least two sets of neighborhood data, for generally simultaneously generating processed result values for each of said at least two sets of neighborhood data.

2. The system as claimed in claim 1, wherein said neighborhood generator comprises at least two FIFO (first-in, first-out) memories through which said image pixel data is cycled.

3. The system as claimed in claim 2, wherein said framing signals comprise start-of-row, end-of row and end-of-frame signals.

7. The improved morphology processing system as claimed in claim 1, wherein said at least one validity checker comprises a plurality of validity checkers, one for each image pixel value in each said set of neighborhood data containing at least three rows and at least four columns of said image pixel data values.

8. The improved morphology processing system as claimed in claim 1, wherein each of said at least two neighborhood processors computes a minimum value of all pixel values in said set of neighborhood data and said background values are selected to be a maximum possible pixel value.

9. The improved morphology processing system as claimed in claim 1, wherein each of said at least two neighborhood processors computes a maximum value of all pixel values in said set of neighborhood data and said background values are selected to be a minimum possible pixel value.

10. The improved morphology processing system as claimed in claim 1, wherein each of said at least two neighborhood processors computes a binary result by forming an integer index value by concatenating input neighborhood data values and looking up a result in a look-up table and wherein said background values are taken from a background value register.

14. The system of claim 1 further comprising:

a background value register, for providing a background value; and

said at least one validity checker responsive to said pixel data, to said background value and to said pixel-valid signal, for outputting said image pixel data to a morphology processor if said pixel-valid signal indicates that said image pixel data is valid, and for outputting said background value to said morphology processor if said pixel-valid signal indicates that said image pixel data is not valid.

15. The system for performing gray scale morphology processing on input data of claim 14 wherein said image pixel data includes gray scale image pixel data having a value of between 0 and 255.

16. The system for performing gray scale morphology processing on input data of claim 14 wherein said input data validity value includes a single bit value having a value of “

0”

if said input data is not valid and a value of “

1”

if said input data is valid.

17. The system for performing gray scale morphology processing on input data of claim 14 wherein said background value has a range of between 0 and 255.

18. The system for performing gray scale morphology processing on input data of claim 17 wherein said background value of “

0”

corresponds to a maximum background value and said background value of “

255”

corresponds to a minimum background data value.

19. The system of claim 1 further comprising;

a background value register, for providing a background value in a range of between 0 and 255, said background value of “

0”

corresponding to a maximum background value and said background value of “

255”

corresponding to a minimum background data value; and

said at least one validity checker responsive to said image pixel data, to said background value and to said pixel-valid signal, for outputting said image pixel data to a morphology processor if said pixel-valid signal indicates that said image pixel data is valid, and for outputting said background value to said morphology processor if said pixel-valid signal indicates that said pixel image-data is not valid.

4. A method for performing morphology computations on one or more adjacent image pixels, said method comprising the steps of:

providing pixel data in groups of adjacent pixels, each said adjacent pixel group containing at least two adjacent image pixel data values;

providing framing signals, said framing signals including a start-of-row, end-of-row and end-of-frame signals;

receiving said pixel data and framing signals, and generating at least two sets of neighborhood data, each said at least two sets of neighborhood data containing at least three rows and at least four columns of said image pixel values and corresponding pixel-valid signals for each image pixel value;

substituting background values in place of said image pixel values when said pixel-valid signal corresponding to said image pixel value is false; and

generally simultaneously processing said at least two sets of neighborhood data and generating processed result values for each of said at last two sets of neighborhood data.

5. The improved morphology processing method as claimed in claim 4, wherein said groups of adjacent pixels comprise groups of four adjacent eight bit pixels.

6. The improved morphology processing method as claimed in claim 5, wherein said step of generating sets of neighborhood data containing at least three rows and at least four columns of said image pixel values and corresponding pixel-valid signals for each image pixel value comprises cycling said image data through at least one two row FIFO (first-in, first-out) memory.

11. The improved morphology processing method as claimed in claim 4, wherein said processing step comprises computing a minimum value of all pixel values in said set of neighborhood data and wherein said background values are selected to be substantially equal to a maximum possible pixel value.

12. The improved morphology processing method as claimed in claim 4, wherein said processing step comprises computing a maximum value of all pixel values in said set of neighborhood data and wherein said background values are selected to be substantially equal to a minimum possible pixel value.

13. The improved morphology processing method as claimed in claim 4, wherein said processing step comprises computing a binary result by forming an integer index value by concatenating input neighborhood data values and looking up a result in a look-up table and wherein said background values are taken from a background value register.

20. A system for performing morphology computations on image pixel data, comprising:

a data flow controller, for providing image pixel data in groups containing at least two adjacent image pixel data values, and for providing framing signals;

a neighborhood generator, for receiving said image pixel data and framing signals and for generating at least two sets of neighborhood data, each of said two sets of neighborhood data containing a plurality of said image pixel data and at least one corresponding pixel-valid signal for each image pixel data value of said plurality of said image pixel data in each said at least two sets of neighborhood data;

at least one validity checker, responsive to said pixel-valid signal for each image pixel data value or said plurality of image pixel data in each said at least two sets of neighborhood data, for substituting background values in place of said image pixel data values when said pixel-valid signal corresponding to said image pixel value is false; and

at least two neighborhood processors, responsive to said at least two sets of neighborhood data and said pixel-valid signal for each image pixel data value in said plurality of image pixel data in each said at least two sets of neighborhood data, for generally simultaneously generating processed result values for each of said at least two sets of neighborhood data.