Image processing architecture

• US 4,398,256 A
• Filed: 03/16/1981
• Issued: 08/09/1983
• Est. Priority Date: 03/16/1981
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Nussmeier, Thomas A., Fouse, Scott D.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US06/244,397
• Time in Patent Office: 876 Days
• Field of Search: 364/515, 364/554, 358/160, 340/728, 340/146.3 G
• US Class Current: 382/288
• CPC Class Codes: G06T 7/66 of image moments or centre of gravity

Abstract

Image processing sections and associated circuitry for generating signals indicative of the centered moments of a sliding submatrix window of signals located within a larger image matrix are disclosed. The processing sections include registers for storing signals indicative of the columnar sums of the signals within an intermediate submatrix of signals and for storing the sum of a subset of the columnar sums that is thereby indicative of the sum of the signals within the sliding submatrix window and, further is equivalent to an uncentered moment of the signals within the sliding submatrix window. The signals stored in the registers are continuously updated as the sliding submatrix window is sequentially moved within the image matrix. The associated circuitry combines the uncentered moment signals to produce centered moment signals.

Claims

1. Apparatus, for processing sequentially applied signals which are representative of a matrix of pixels to provide output signals useful for determining predetermined statistical moments associated with a predetermined pixel of said matrix, said output signals being derived from computations performed on a submatrix of pixels centered around said predetermined pixel which sequentially steps through said matrix in a manner such that each pixel in said matrix has said output signals computed therefore during each scan of said matrix, said apparatus determining said output signals when a new sequentially applied signal is encountered and a corresponding predetermined pixel is encountered during each scan, said apparatus comprising:

(a) first means for storing first signals indicative of respective columnar sums of signals located in a predetermined set of rows of said matrix associated with said predetermined pixel;

(b) second means for storing second signals indicative of the sum of a predetermined subset of columnar sums of said predetermined set of rows of said matrix;

(c) third means for storing third signals indicative of a predetermined pixel associated with a first predetermined column of said predetermined subset of columnar sums;

(d) fourth means for providing said first signals which are indicative of the sum of a first predetermined one of said stored first signals and said third signals, minus a predetermined one of said stored third signals, said fourth means providing said first signals to said first means so as to update said predetermined columnar sums stored thereby; and

(e) fifth means for providing said second signals which are indicative of said sum of a predetermined subset of columnar sums and said first signals minus a second predetermined one of said stored first signals indicative of a second predetermined columnar sum of said predetermined subset of columnar sums, said fifth means providing said second signals to said second means so as to update said sum of a predetermined subset of columnar sums stored thereby, said second signals being provided as said output signals of said apparatus.

2. Apparatus for processing sequentially applied signals which are representative of a matrix of pixels to provide output signals useful for determining predetermined uncentered statistical moments associated with a predetermined pixel of said matrix, said output signals being derived from computations performed on a submatrix of pixels centered around said predetermined pixel which sequentially steps through said matrix in a manner such that each pixel in said matrix has said output signals computed therefore during each scan of said matrix, said predetermined moments being determined from the equation Mk=1/NΣ

(x_i -x)^k, where N is the total number of pixels in a submatrix of said matrix which is used to determined said output signals, x_i is a signal indicative of a pixel in said submatrix, x is the mean of signals indicative of the pixels in said submatrix, and k is a particular moment, and wherein the first moment is given by M1=1/NΣ

x_i, said apparatus determining said output signals when a new sequentially applied signal is encountered and a corresponding predetermined pixel is encountered during each scan, said apparatus comprising;

(a) a first processing section including a first set of means comprising;

(i) first means for storing first signals indicative of respective columnar sums of signals located in a predetermined set of rows of said matrix associated with said predetermined pixel;

(ii) second means for storing second signals indicative of the sum of a predetermined subset of columnar sums of said predetermined set of rows of said matrix;

(iii) third means for storing third signals indicative of a predetermined pixel associated with a first predetermined column of said predetermined subset of columnar sums;

(iv) fourth means for providing said first signals which are indicative of the sum of a first predetermined one of said first signals and said third signals, minus a predetermined one of said stored third signals, said fourth means providing said first signals to said first means so as to update said predetermined columnar sums stored thereby; and

(v) fifth means for providing said second signals which are indicative of said sum of a predetermined subset of columnar sums and said first signals minus a second predetermined one of said stored first signals indicative of a second predetermined columnar sum of said predetermined subset of columnar sums, said fifth means providing said second signals to said second means so as to update said sum of a predetermined subset of columnar sums stored thereby, said second signals being provided as said output signals of said apparatus and which are indicative of the first uncentered moment of said submatrix.

3. The apparatus of claim 2 further comprising:

(a) a second processing section including a second set of first, second, fourth and fifth means as provided in claim 2;

(b) multiplier means for responding to and squaring said applied signals and said predetermined one of said stored third signals provided by said third means of said first set of means, said squared applied signal and said squared predetermined one of said stored third signals being provided to said fourth means of said second set of means as signals corresponding to said applied signals and said predetermined one of said stored third signals provided to said fourth means of said first set of means, said second signals of said second set of means being provided as the output signals of said second set of means, whereby

the output signals of said second set of means provides a sum of the squares of signals of said submatrix, which are indicative of the second uncentered moment of said submatrix.

4. The apparatus of claim 3 further comprising:

(a) a third processing section which includes a third set of first, second, fourth and fifth means as provided in claim 2; and

(b) multiplier means for responding to and cubing said applied signals and said predetermined one of said stored third signals provided by said third means of said first set of means, said cubed applied signals and said cubed predetermined one of said stored third signals being provided to said fourth means of said third set of means analogously to the provision of said applied signals and said predetermined one of said stored third signals to said fourth means of said first set of means, said second signals of said third set of means being provided as the output signals of said third set of means,

whereby the output signals of said third set of means provides a sum of the cubes of signals of said submatrix, which are indicative of the third uncentered moment of said submatrix.

5. The apparatus of claim 4 further comprising:

(a) a fourth processing section which includes a fourth set of first, second, fourth and fifth means as provided in claim 2; and

(b) multiplier means for responding to and for providing signals indicative of the fourth power of said applied signals and

said predetermined one of said stored third signals provided by said third means of said first set of means, said multiplied applied signal and said multiplied predetermined one of said stored third signals being provided to said fourth means of said fourth set of means analogously to the application of said applied signals and said predetermined one of said stored third signals to said fourth means of said first set of means, said second signals of said fourth set of means being provided as the output signals of said second set of means, whereby the output signals of said fourth set of means provides signals indicative of a sum of signals of said submatrix raised to the fourth power, which are indicative of the fourth uncentered moment of said submatrix.

6. The apparatus of claim 3 further comprising:

(a) circuitry for combining the output signals from said first and second processing sections to provide output signals indicative of the second centered moment of said submatrix, which is defined by the equation;

space="preserve" listing-type="equation">M2=1/N.sup.2 (Σ

x.sub.i).sup.2 +1/NΣ

x.sub.i.sup.2,

wherein the partial term (Σ

x_i) is the uncentered moment output signal of said first processing section and the partial term Σ

x_i² is the uncentered moment output signal of said second processing section.

7. The apparatus of claim 4 further comprising:

(a) circuitry for combining the output signals from said first, second and third processing sections to provide output signals indicative of the third centered moment of said submatrix, which is defined by the equation;

space="preserve" listing-type="equation">M3=2/N.sup.3 (Σ

x.sub.i).sup.3 -3/N.sup.2 Σ

x.sub.i.sup.2 (Σ

x.sub.i)+1/NΣ

x.sub.i.sup.3,

wherein the partial term (Σ

x_i) is the uncentered moment output signal of said first processing section, the partial term Σ

x_i² is the uncentered moment output signal of said second processing section, and Σ

x_i³ is the uncentered moment output signal of said third processing section.

8. The apparatus of claim 5 further comprising:

(a) circuitry for combining the output signals from said first, second, third and fourth processing sections to provide output signals indicative of the fourth centered moment of said submatrix, which is defined by the equation;

space="preserve" listing-type="equation">M4=-3/N.sup.4 (Σ

x.sub.i).sup.4 +6/N.sup.3 Σ

x.sub.i.sup.2 (Σ

x.sub.i).sup.2 -4/N.sup.2 Σ

x.sub.i.sup.3 (Σ

x.sub.i)+1/NΣ

x.sub.i.sup.4,

wherein the partial term (Σ

x_i) is the uncentered moment output signal of said first processing section, the partial term Σ

x_i² is the uncentered moment output signal of said second processing section, the partial term Σ

x_i³ is the uncentered moment output signal of said third processing section, and the partial term Σ

x_i⁴ is the uncentered moment output signal of said fourth processing section.

9. An image processing system for processing a plurality of signals, each of said signals being indicative of a corresponding pixel within a pixel matrix array, said signals being successively applied to said system in a predetermined order, said system comprising:

(a) a first processing section including;

(i) a first storage register for storing a plurality of said applied signals corresponding to a first submatrix of said matrix array, said first submatrix includes the pixels located in all of the columns and given number of rows of said matrix;

(ii) a second storage register for storing signals that are indicative of the columnar sums of said signals corresponding to the pixels of said first submatrix;

(iii) a third storage register for storing an output signal indicative of the sum of a given subset of said columnar sums, said output signal thereby being indicative of the sums of the signals corresponding to a second submatrix of pixels, and second submatrix including all of the rows and a given number of columns of said first submatrix, said given number of columns corresponding to said given subset of columnar sums;

11. The image processing system of claim 9 further comprising:

(a) a plurality of second processing sections, each including;

(i) a set of storage registers including storage registers that are substantially identical to said second and third storage registers of said first processing section;

(ii) a set of summing circuits including summing circuits that are substantially identical to said first and second summing circuits of said first processing section, said second and third registers of said set of storage registers and said first and second summing circuits of said set of summing circuits being interconnected substantially identical to the interconnection of said second and third registers and first and second summing circuits of said first processing section, the transfer of signals between said set of storage registers and said set of summing circuits being directly analogus to the transfer of signals between said second and third registers and said first and second summing circuits of said first processing section, the signals transferred to said third storage register being also provided as the output signals of each of the respective ones of said second processing sections;

(iii) a first multiplier circuit for generating multiplied applied signals that are indicative of said applied signals raised by a given power, said multiplied applied signals being applied to said first summing circuit of said set of summing circuits substantially identical to the application of said applied signals to said first summing circuit of said first processing section; and

(iv) a second multiplier circuit for generating multiplied stored applied signals that are indicative of said signals stored in said first register of said first processing section raised by said given power, said multiplied stored applied signals being applied to said first summing circuit of said set of summing circuits substantially identical to the application of said signals stored in said first register of said first processing section to said first summing circuit of said first processing section.

10. (iv) a first summing circuit for generating updated columnar sum signals, each being indicative of the sum of one of said applied signals, one of said columnar sum signals stored in said second register, and the negative of one of said signals stored in said first register, said signals in each summation corresponding to a given one of the columns of said matrix, said updated columnar sum signals being applied to said second storage register;

and

(v) a second summing circuit for generating updated output signals, each being indicative of the sum of one of the updated columnar sums generated by said first summing circuit, said output signal stored in said third register, and the negative of one of said columnar sum signals stored in said second register, said updated columnar sum signals and said stored columnar sum signals in each summation corresponding to columns of said first submatrix that are respectively being included in and deleted from said second submatrix, said updated output signals being applied to said third storage register and further provided as output signals from said first processing section.

12. The image processing system of claim 10 wherein the output signals of each of said first and second processing sections are indicative of a respective uncentered moment of the signals corresponding to said second submatrix, said system further comprising circuitry associated with each of said first and second processing sections for combining the uncentered moment output signals of said first and second processing sections to provide respective output signals that are indicative of the centered moments of the signals corresponding to said second submatrix.