Apparatus and method for controlling a moving vehicle utilizing a digital differential analysis circuit
First Claim
1. A device for detecting a boundary of a roadway upon which a vehicle travels, the device comprising:
- camera means for generating electronic signals representing an image of the roadway, the image comprising a view of the roadway extending in a direction of travel of the vehicle;
a signal inputting unit for digitizing the signals representing the image of the roadway;
an edge detecting unit for processing the digitized signals to produce edged picture element signals differentiated with respect to pixel to pixel brightness variations;
a preprocessing unit for receiving the edged picture element signals from the edge detecting unit and storing in a multivalue memory circuit edged picture data corresponding to the edged picture element signals, the edged picture data corresponding to each edged picture element signal comprising an address in an X-Y coordinate system and an edged brightness value;
digital differential analysis computing means including a plurality of digital differential analysis computing circuits which are serially connected, each for converting the addresses of the edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, and said rotary motion recurrence formula comprising the equation
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i -2.sup.-m β
.sub.i ;
and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i+1 +β
.sub.iwherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . );
a histogram memory circuit for storing address data corresponding to the intersection points between the generated approximate HOUGH curves; and
a processor for generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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Abstract
This invention relates to a picture processing device in which picture data of a road or lines marking off a lane taken by a television camera installed on a vehicle is processed for the recognition of the contour of the road or the lane. Picture data is analog/digital converted, then edited and is subjected to the binary processing to be supplied to a digital differential analysis computing circuit. The digital differential analysis circuit comprises circuits serially connected each of which computes a rotary motion recurrence formula every rotation by a rotation angle. The recurrence formula is computed in the pipe-line system. In this computation the Hough transform is performed to give sine curves in a ρ-θ coordinate system. The points of intersection of these sine curves (Hough curves) are given, and those of them having more occurrences are selected in the ρ-θ coordinate system. Resultantly, the contour of the shoulder lines and the center line of the road, or the contour of the lane are given.
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Citations
12 Claims
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1. A device for detecting a boundary of a roadway upon which a vehicle travels, the device comprising:
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camera means for generating electronic signals representing an image of the roadway, the image comprising a view of the roadway extending in a direction of travel of the vehicle; a signal inputting unit for digitizing the signals representing the image of the roadway; an edge detecting unit for processing the digitized signals to produce edged picture element signals differentiated with respect to pixel to pixel brightness variations; a preprocessing unit for receiving the edged picture element signals from the edge detecting unit and storing in a multivalue memory circuit edged picture data corresponding to the edged picture element signals, the edged picture data corresponding to each edged picture element signal comprising an address in an X-Y coordinate system and an edged brightness value; digital differential analysis computing means including a plurality of digital differential analysis computing circuits which are serially connected, each for converting the addresses of the edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, and said rotary motion recurrence formula comprising the equation
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i -2.sup.-m β
.sub.i ;and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i+1 +β
.sub.iwherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . );a histogram memory circuit for storing address data corresponding to the intersection points between the generated approximate HOUGH curves; and a processor for generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves. - View Dependent Claims (2, 3)
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4. A machine implemented process for detecting a boundary of a roadway upon which a vehicle travels, the process comprising the steps of:
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generating electronic signals representing an image of the roadway, the image comprising a view of the roadway in a direction of travel of the vehicle; digitizing the signals representing the image of the roadway; generating edged picture element signals from the digitized signals, the edged picture element signals being differentiated with respect to pixel to pixel brightness; storing in a memory circuit edged picture data corresponding to the edged picture element signals, the edges picture data comprising addresses in an X-Y coordinate system and edged brightness values; converting the addresses of the stored edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, using a digital differential analysis computing means including a plurality of serially connected differential analysis computing circuits, said rotary motion recurrence formula comprising the equations
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i -2.sup.-m β
.sub.i ;and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i+1 +β
.sub.iwherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=.sup.- m (rad) (m=0, 1, 2, . . . );storing address data corresponding to the intersection points between the generated approximate HOUGH curves and a histogram memory circuit; and generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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5. A machine implemented process for generating a plurality of approximate HOUGH curves in a ρ
- -θ
coordinate system, said process comprising the steps of;generating pixel data representative of an image, said pixel data comprising addresses in an X-Y coordinate system and pixel brightness values; storing said pixel data in a memory circuit; retrieving said pixel data from said memory circuit; and
using a digital differential analysis computing means including an initial value computing circuit and a plurality of serially connected digital differential analysis circuits, converting the addresses of the retrieved pixel data from the X-Y coordinate system to an α
-β
coordinate system and processing said converted pixel data using a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, said rotary motion recurrence formula being defined by the following equations;
space="preserve" listing-type="equation">α
.sub.i+1 =f.sub.α
(α
.sub.i,β
.sub.i,ε
)
space="preserve" listing-type="equation">β
.sub.i+1 =f.sub.β
(α
.sub.i,β
.sub.i,ε
). - View Dependent Claims (6, 7, 8)
- 7. The machine implemented process of claim 5, wherein said rotary motion recurrence formula comprises the equations
- space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2.sup.-2m-1)-2.sup.-β
.sub.i ;
and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i +β
.sub.i (1-2.sup.-m-1)wherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . ). - space="preserve" listing-type="equation">α
- -θ
- 8. The machine implemented process of claim 5, wherein said rotary motion recurrence formula comprises the equations
- space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2-2m-1)+β
.sub.i (-.sup.-m +ε
.sup.-3m /6);
and
space="preserve" listing-type="equation">β
.sub.i+1 =α
.sub.i (2.sup.-m +ε
.sup.-3m
6)+β
.sub.i (1-2.sup.-2m-1)wherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . ). - space="preserve" listing-type="equation">α
-
9. A device for detecting a boundary of a roadway upon which a vehicle travels, the device comprising:
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camera means for generating electronic signals representing an image of the roadway, the image comprising a view of the roadway extending in a direction of travel of the vehicle; a signal inputting unit for digitizing the signals representing the image of the roadway; an edge detecting unit for processing the digitized signals to produce edged picture element signals differentiated with respect to pixel to pixel brightness variations; a preprocessing unit for receiving the edged picture element signals from the edge detecting unit and storing in a multivalue memory circuit edged picture data corresponding to the edged picture element signals, the edged picture data corresponding to each edged picture element signal comprising an address in an X-Y coordinate system and an edged brightness value; digital differential analysis computing means including a plurality of digital differential analysis computing circuits which are serially connected, each for converting the addresses of the edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, and said rotary motion recurrence formula comprising the equation
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2.sup.-2m-1)-2.sup.-m β
.sub.i ;and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i +β
.sub.i (1-2.sup.-2m-1)wherein an angle of rotation comprises ε
=- m (rad) (m=0, 1, 2, . . . );a histogram memory circuit for storing address data corresponding to the intersection points between the generated approximate HOUGH curves; and a processor for generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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10. A device for detecting a boundary of a roadway upon which a vehicle travels, the device comprising:
-
camera means for generating electronic signals representing an image of the roadway, the image comprising a view of the roadway extending in a direction of travel of the vehicle; a signal inputting unit for digitizing the signals representing the image of the roadway; an edge detecting unit for processing the digitized signals to produced edged picture element signals differentiated with respect to pixel to pixel brightness variations; a preprocessing unit for receiving the edged picture element signals from the edge detecting unit and storing in a multivalue memory circuit edged picture data corresponding to the edged picture element signals, the edged picture data corresponding to each edged picture element signal comprising an address in an X-Y coordinate system and an edged brightness value; digital differential analysis computing means including a plurality of digital differential analysis computing circuits which are serially connected, each for converting the addresses of the edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, and said rotary motion recurrence formula comprising the equations
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2-2m-1)+β
.sub.i (-2.sup.-m +ε
.sup.-m /6);and
space="preserve" listing-type="equation">β
.sub.i+1 =α
.sub.i (2.sup.-m +ε
.sup.-m /6)+β
.sub.i (1-2.sup.-2m-1)wherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=.sup.- m (rad) (m=0, 1, 2, . . . );a histogram memory circuit for storing address data corresponding to the intersection points between the generated approximate HOUGH curves; and a processor for generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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11. A machine implemented process for detecting a boundary of a roadway upon which a vehicle travels, the process comprising the steps of:
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generating electronic signals representing an image of the roadway, the image comprising a view of the roadway in a direction of travel of the vehicle; digitizing the signals representing the image of the roadway; generating edged picture element signals from the digitized signals, the edged picture element signals being differentiated with respect to pixel to pixel brightness; storing in a memory circuit edged picture data corresponding to the edged picture element signals, the edges picture data comprising addresses in an X-Y coordinate system and edged brightness values; converting the addresses of the stored edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, using a digital differential analysis computing means including a plurality of serially connected differential analysis computing circuits, said rotary motion recurrence formula comprising the equations
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2.sup.-2m-1)-2.sup.-m β
.sub.i ;and
space="preserve" listing-type="equation">β
.sub.i+1 =2.sup.-m α
.sub.i+β
.sub.i (1-2.sup.-2m-1)wherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . );storing address data corresponding to the intersection points between the generated approximate HOUGH curves and a histogram memory circuit; and generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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12. A machine implemented process for detecting a boundary of a roadway upon which a vehicle travels, the process comprising the steps of:
-
generating electronic signals representing an image of the roadway, the image comprising a view of the roadway in a direction of travel of the vehicle; digitizing the signals representing the image of the roadway; generating edged picture element signals from the digitized signals, the edged picture element signals being differentiated with respect to pixel to pixel brightness; storing in a memory circuit edged picture data corresponding to the edged picture element signals, the edges picture data comprising addresses in an X-Y coordinate system and edged brightness values; converting the addresses of the stored edged picture data from the X-Y coordinate system to an α
-β
coordinate system and computing a rotary motion recurrence formula to generate a plurality of approximate HOUGH curves in a ρ
-θ
coordinate system, the approximate HOUGH curves intersecting at a plurality of points in the ρ
-θ
coordinate system, using a digital differential analysis computing means including a plurality of serially connected differential analysis computing circuits, said rotary motion recurrence formula comprising the equations
space="preserve" listing-type="equation">α
.sub.i+1 =α
.sub.i (1-2-2m-1)+β
.sub.i (-2.sup.-m +ε
.sup.-3m /6);and
space="preserve" listing-type="equation">β
.sub.i+1 =α
.sub.i (2.sup.-m +ε
.sup.-3m /6)+β
.sub.i (1-2.sup.-2m-1)wherein an angle of rotation comprises
space="preserve" listing-type="equation">ε
=2.sup.-m (rad) (m=0, 1, 2, . . . );storing address data corresponding to the intersection points between the generated approximate HOUGH curves and a histogram memory circuit; and generating a signal representing the boundary of the roadway based on the stored address data corresponding to the intersection points of the approximate HOUGH curves.
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Specification