Apparatus for and method of hough-converting coordinate data

• US 5,220,615 A
• Filed: 12/21/1990
• Issued: 06/15/1993
• Est. Priority Date: 12/27/1989
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Hasegawa, Hiroshi, Ishii, Jun
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): Cammarata, Michael
• Application Number:
  US07/632,062
• Time in Patent Office: 907 Days
• Field of Search: 382/1, 382/9, 382/41, 382/43, 364/413.2, 364/576, 364/725, 364/728.02
• US Class Current: 382/281
• CPC Class Codes: G06F 17/145 Square transforms, e.g. Hadamard, Walsh, Haar, Hough, Slant transforms
• CPC Class Codes: G06V 10/753 Transform-based matching, e.g. Hough transform
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

Disclosed herein is an apparatus for and a method of Hough-converting coordinate data in a rectangular coordinate system. The apparatus includes circulating means for receiving prescribed data corresponding to the coordinate data therein so as to successively add prescribed numbers to the prescribed data while circulating the prescribed data. In addition, the method includes the steps of determining Hough conversion data corresponding to the following coordinate data (x+g, y) in the x-axis direction of coordinate data (x, y) in accordance with the following equation:

ρ(x+g, y, θ.sub.n)=ρ(x, y, θ.sub.n)+a

where a and g are constants, and a=g·cosθ_n, when the equation for the Hough conversion of the coordinate data (x, y) at the time the coordinate data are set as (x, y) is given by the following equation:

ρ(x, y, θ.sub.n)=x·cosθ.sub.n

+y·sinθ_n ;

and determining Hough conversion data corresponding to the following coordinate data (x, y+h) in the y-axis direction of the coordinate data (x, y) in accordance with the following equation:

ρ)x, y+h, θ.sub.n)=ρ(x, y, θ.sub.n)+b

where b and h are constants, and b=h·sinθ_n.

Claims

1. An apparatus for performing Hough conversion of coordinate data in a rectangular coordinate system, comprising:

first register means for receiving and storing first Hough conversion data therein;

first adding means connected to said first register means for successively adding prescribed numbers to said first Hough conversion data and outputting the result of addition therefrom, wherein an output of said first register means is connected to one input of said first adding means;

first circulating means comprising a first flip-flop connected to said adding means for circulating said first Hough conversion data through said first adding means as said prescribed numbers are successively added to said first Hough conversion data, wherein an output of said first flip-flop is connected to another input of said first adding means;

second register means for receiving and storing second Hough conversion data therein;

second adding means connected to said register means for successively adding prescribed numbers to said second Hough conversion data and outputting the result of addition therefrom, wherein an output of said second register means is connected to one input of said second adding means; and

second circulating means comprising a second flip-flop connected to said second adding means for circulating said second Hough conversion data through said second adding means as said prescribed numbers are successively added to said second Hough conversion data, wherein an output of said second flip-flop is connected to another input of said second adding means.

2. An apparatus for performing Hough conversion of coordinate data in a rectangular coordinate system, comprising:

first register means for receiving and storing first Hough conversion data therein;

first adding means connected to said first register means for receiving therein said first Hough conversion data corresponding to a first coordinate and successively adding prescribed numbers to said first Hough conversion data and outputting the result of addition therefrom;

first circulating means comprising a first flip-flop connected to said first adding means for circulating said first Hough conversion data through said first adding means as said prescribed numbers are successively added to said first Hough conversion data, wherein an output of said first circulating means is connected to an input of said first adding means;

second register means for receiving and storing second Hough conversion data therein;

second adding means connected to said second register means for receiving therein said second Hough conversion data corresponding to a second coordinate and successively adding prescribed numbers to said second Hough conversion data and outputting the result of addition therefrom; and

second circulating means comprising a second flip-flop connected to said second adding means for circulating said second Hough conversion data through said second adding means as said prescribed numbers are successively added to said second Hough conversion data;

wherein an output of said second circulating means is connected to an input of said second adding means;

wherein an output of said first circulating means is accumulatively added to the output of said second circulating means each time said second Hough conversion data is circulated a predetermined umber of times by said second circulating means.

3. An apparatus according to claim 2, wherein said first circulating means comprises a first memory means for holding first circulating data therein for each circulating thereof, said first adding means receiving said first circulating data stored in said first memory means and said first Hough conversion data therein so as to add the two data together, thereby supplying the result thus added to said first memory means.

4. An apparatus according to claim 3, wherein said second circulating means comprises a second memory means for holding second circulating data therein for each circulation thereof, wherein said second adding means receives said second circulating data stored in said second memory means and said second Hough conversion data therein so as to add the two data together, thereby supplying the result thus added to said second memory means.

5. An apparatus according to claim 4, wherein said first and second memory means comprise said first and second flip-flops respectively.

6. An apparatus according to claim 4, further comprising a selecting means having two inputs for receiving data therein, wherein one of said inputs receives an output of said first adding means comprising the result of addition of said first circulating data and said first Hough conversion data, and the other of said inputs receives an output of said second adding means comprising the result of addition of said second circulating data and said second Hough conversion data, said selecting means selecting one of said two inputs.

7. An apparatus according to claim 6, wherein said selecting means comprises a multiplexer.

8. An apparatus for consecutively reading Hough conversion data in a x-axis direction from a two-dimensional (x,y) coordinate system in which coordinate values (x,y) of said two-dimensional coordinate system are varied at prescribed intervals (g,h) continuously while scanning said data in an x-axis direction, wherein said x-axis direction comprises a main scanning direction and said y-axis direction comprises a sub-scanning direction, thereby performing Hough conversion of said coordinates in accordance with the following equation:

space="preserve" listing-type="equation">ρ

(x, y, θ

.sub.n)=x·

cosθ

.sub.n +y·

sinθ

.sub.n

wherein θ

_n is an angle between the x-axis and a straight line segment defined by said Hough conversion data, said apparatus comprising;

first register means for receiving and storing first Hough conversion data therein having a value h·

sinθ

_n, wherein h has a predetermined value;

first adding means connected to said first register means for receiving therein said first Hough conversion data and adding a multiple of said value h·

sinθ

_n to said first Hough conversion data each time said y-coordinate is successively incremented by said prescribed interval h, thereby outputting y-coordinate data corresponding to y·

sinθ

_n ;

first circulating means comprising a first flip-flop connected to said first adding means for circulating the y-coordinate data through said first adding means as said y-coordinate is successively incremented by said prescribed internal h, wherein an output of said first circulating means is connected to an input of said first adding means;

second register means for receiving and storing second Hough conversion data therein having a value g·

cosθ

_n, wherein g has a predetermined value;

second circulating means comprising a second flip-flop connected to said second adding means for circulating the x-coordinate data through said second adding means as said x-coordinate is successively incremented by said prescribed interval g, wherein an output of said second circulating means is connected to an input of said second adding means; and

output means for selectively outputting the outputs of said first and second circulating means, wherein the output of said first circulating means is selected each time said x-coordinate data is circulated a predetermined number of times by said second circulating means, thereby outputting data corresponding to x·

cosθ

_n +y·

sinθ

_n.

9. An apparatus according to claim 8, wherein said first circulating means comprises a first memory means for holding and updating said y-coordinate data therein for each circulation of said circulating means, said first adding means receiving said y-coordinate data stored in said first memory means and said first Hough conversion data therein so as to add the two data together, thereby supplying the result thus added to said first memory means for updating said y-coordinate data.

10. An apparatus according to claim 9, wherein said second circulating means comprises a second memory means for holding and updating said x-coordinate data therein for each circulation of said circulating means, said second adding means receiving said x-coordinate data stored in said second memory means and said second Hough conversion data therein so as to add the two data together, thereby supplying the result thus added to said second memory means for updating said x-coordinate data.

11. An apparatus according to claim 10, wherein said first and second memory means comprise said first and second flip-flops respectively.

12. An apparatus according to claim 10, wherein said output means comprises at least one multiplexer for receiving the output data of said first circulating means and the output of said second adding means.

13. An apparatus according to claim 12, further comprising a third register means for receiving and storing therein data having a value x₀ ·

cosθ

_n +Y₀ ·

sinθ

_n, wherein x₀ and y₀ are predetermined initial values, and means for setting said third register means to an initial value at the time of start of addition by said first adding means.

14. An apparatus according to claim 13, further comprising another multiplexer for receiving the output of said third register and the output of said first adding means.

15. An apparatus for consecutively reading Hough conversion data in a y-axis direction from a two-dimensional (x, y) coordinate system in which coordinate values (x, y) of said two-dimensional coordinate system are varied at prescribed intervals (g,h) continuously while scanning said data in an x-axis direction, wherein said x-axis direction comprises a main scanning direction and said y-axis direction comprises a sub-scanning direction, thereby performing Hough conversion of said coordinates in accordance with the following equation:

space="preserve" listing-type="equation">ρ

(x, y, θ

.sub.n)=x·

cosθ

.sub.n +y·

sinθ

.sub.n

wherein θ

_n is and angle between the x-axis and a straight line segment defined by said Hough conversion, data, said apparatus comprising;

a plurality of processing elements connected in series, wherein in each of said processing elements performs processing with respect to a variable θ

_n, wherein θ

_n is different in each of said processing elements, each of said processing elements comprising;

first register means for receiving and storing first Hough conversion data therein having a value h·

sinθ

_n, wherein h has a predetermined value;

first adding means connected to said first register means for receiving therein said first Hough conversion data and adding a multiple of said value h·

sinθ

_n to said first Hough conversion data each time said y-coordinate is successively incremented by said prescribed interval h, thereby outputting y-coordinate data corresponding to y·

sinθ

_n ;

first circulating means comprising a first flip-flop connected to said first adding means for circulating the y-coordinate data through said first adding means as said y-coordinate is successively incremented by said prescribed interval h, wherein an output of said first circulating means is connected to an input of said first adding means;

second register means for receiving and storing second Hough conversion data therein having a value g·

cosθ

_n, wherein g has a predetermined value;

second adding means for receiving therein said second Hough conversion data and adding a multiple of said value g·

cosθ

_n, to said second Hough conversion data each time said x-coordinate is successively incremented by said prescribed interval g, thereby outputting x-coordinate data corresponding to x·

cosθ

_n ; and

second circulating means comprising a second flip-flop connected to said second adding means for circulating the x-coordinate data through said second adding means as said x-coordinate is successively incremented by said prescribed interval g, wherein an output of said second circulating means is connected to an input of said second adding means;

output means for selectively outputting the outputs of said first and second circulating means, wherein the output of said first circulating means is selected each time said x-coordinate data is circulated a predetermined number of times by said second circulating means, thereby outputting data corresponding to x·

cosθ

_n +y·

sinθ

_n.

16. An apparatus for consecutively reading Hough conversion data from a two-dimensional (x,y) coordinate system in which coordinate values (x,y) of said two-dimensional coordinate system are varied at prescribed intervals (g,h) continuously while scanning said data in an x-axis direction, wherein said x-axis direction comprises a main scanning direction and said y-axis direction comprises a subscanning direction, thereby performing Hough conversion of said coordinates in accordance with the following equation:

space="preserve" listing-type="equation">ρ

(s, y, θ

.sub.n)=x·

cosθ

.sub.n +y·

sinθ

.sub.n

wherein θ

_n is an angle between the x-axis and a straight line segment defined by said Hough conversion data, said apparatus comprising;

first register means for receiving and storing first Hough conversion data therein having a value sinθ

_n -l·

cosθ

_n, wherein l is a predetermined constant indicating a length of said (x,y) coordinate system in the x-direction;

second register means for receiving and storing second Hough conversion data therein having a value g·

cosθ

_n, wherein g has a predetermined value;

selecting means connected to said first and second register means for receiving therein the contents of the data stored in said first and second register means and for selecting and outputting one of said contents of said first and second register means;

adding means connected to an output of said selecting means for receiving therein said second Hough conversion data and adding a multiple of said value g·

cosθ

_n to said second Hough conversion data each time said x-coordinate is successively incremented by said prescribed interval g, and for receiving therein said first Hough conversion data and adding said first Hough conversion data to the result of addition of said multiple of said value g·

cosθ

_n and said second Hough conversion data each time said addition is repeated l times, thereby outputting (x,y) coordinate data; and

circulating means comprising a flip-flop connected to said adding means for circulating the (x,y) coordinate data through said adding means as said x and y coordinates are successively incremented by said prescribed intervals g and h, wherein an output of said circulating means is connected to an input of said adding means.

17. An apparatus according to claim 16, wherein said circulating means comprises a memory means for holding and updating said (x,y) coordinate data therein for each circulation of said circulating means, said adding means receiving said (x,y) coordinate data stored in said memory means and one of said first and second Hough conversion data therein so as to add said (x,y) coordinate data to one of said first and second Hough conversion data, and thereby supplying the result thus added to said memory means for updating said (x,y) coordinate data.

18. An apparatus according to claim 16, wherein said selecting means comprises a multiplexer.

19. An apparatus according to claim 17, wherein said memory means comprises said flip-flop.