METHOD AND DEVICE FOR TYRE CONDITION ANALYSIS
First Claim
1. A method of assessing the condition of a tyre on a wheel which is mounted on a vehicle, while the vehicle is moving and the tyre is rotating and moving longitudinally along a path of movement over a base, the periphery of the tyre having tread portions separated by tread gaps;
- in which the method comprises using an imaging device to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution, the images being captured whilst a light source is activated to illuminate the portions of the periphery of the tyre; and
the images are analysed to determine the depth of the tread gaps;
whereina series of a plurality of light sources is positioned to one side of the path of movement of the tyre, each light source being a point source of non-collimated light and directing light at an acute angle to the path of movement of the tyre;
the light sources being spaced from each other in a longitudinal direction;
a control system is configured to activate the light sources sequentially whilst the tyre moves along said path of movement, so that only one of said light sources of the series illuminates a portion of the periphery of the tyre when an image is being captured by the imaging device of that portion of the periphery of the tyre;
when a light source is activated to illuminate a portion of the periphery of the tyre, the light source causes shadows to be cast in the tread gaps between tread portions;
the imaging device is operated to collect an image of at least part of the illuminated portion of the periphery of the tyre; and
the image is analysed by data processing apparatus which determines the extent of the shadow in a tread gap so as to provide an indication of the depth of the tread gap.
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Accused Products
Abstract
A system for measuring the depth of tread of a tyre (5) on a wheel (2) of a vehicle (1) whilst the wheel is rotating and moving along the ground. A camera (3) captures images whilst the tyre rotates for at least the major part of its circumference. Light sources (L1 to L4) are spaced longitudinally and are directed at an acute angle to the path of the tyre, to illuminate the tyre whilst images are captured. The images are analysed by data processing apparatus (8) and the tread depth is determined from the length of shadows (12, 13) in the gaps (11) between tread blocks (10). The light sources are activated and de-activated sequentially in accordance with signals from longitudinally spaced sensors (S1 to S4) which detect the presence of the tyre, so that when an image is captured of a portion of the tyre tread, only one light source is activated to illuminate that portion of the tyre tread.
38 Citations
15 Claims
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1. A method of assessing the condition of a tyre on a wheel which is mounted on a vehicle, while the vehicle is moving and the tyre is rotating and moving longitudinally along a path of movement over a base, the periphery of the tyre having tread portions separated by tread gaps;
- in which the method comprises using an imaging device to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution, the images being captured whilst a light source is activated to illuminate the portions of the periphery of the tyre; and
the images are analysed to determine the depth of the tread gaps;
whereina series of a plurality of light sources is positioned to one side of the path of movement of the tyre, each light source being a point source of non-collimated light and directing light at an acute angle to the path of movement of the tyre;
the light sources being spaced from each other in a longitudinal direction;a control system is configured to activate the light sources sequentially whilst the tyre moves along said path of movement, so that only one of said light sources of the series illuminates a portion of the periphery of the tyre when an image is being captured by the imaging device of that portion of the periphery of the tyre; when a light source is activated to illuminate a portion of the periphery of the tyre, the light source causes shadows to be cast in the tread gaps between tread portions;
the imaging device is operated to collect an image of at least part of the illuminated portion of the periphery of the tyre; and
the image is analysed by data processing apparatus which determines the extent of the shadow in a tread gap so as to provide an indication of the depth of the tread gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- in which the method comprises using an imaging device to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution, the images being captured whilst a light source is activated to illuminate the portions of the periphery of the tyre; and
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11. Apparatus for assessing the condition of a vehicle tyre on a wheel, whilst the tyre is rotating and moving longitudinally along a path of movement over a base, the periphery of the tyre having tread portions separated by tread gaps;
- in which the apparatus comprises an imaging device and a light source, the imaging device being arranged to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution, the images being captured whilst the light source is activated to illuminate the portions of the periphery of the tyre; and
a data processing system configured to process the images to enable the depth of the tread gaps to be determined;
whereina series of a plurality of light sources is positioned to one side of the path of movement of the tyre, each light source being a point source of non-collimated light and directing light at an acute angle to the path of movement of the tyre;
the light sources being spaced from each other in a longitudinal direction;a control system is configured to activate the light sources sequentially whilst the tyre moves along said path of movement, so that only one of said light sources of the series illuminates a portion of the periphery of the tyre when an image is being captured by the imaging device of that portion of the periphery of the tyre; when a light source is activated to illuminate a portion of the periphery of the tyre, the light source causes shadows to be cast in the tread gaps between tread portions; the imaging device being arranged to collect an image of at least part of the illuminated portion of the periphery of the tyre; and
data processing system is configured to analyse the image so as to determine the extent of the shadow in a tread gap so as to provide an indication of the depth of the tread gap. - View Dependent Claims (12, 13, 14)
- in which the apparatus comprises an imaging device and a light source, the imaging device being arranged to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution, the images being captured whilst the light source is activated to illuminate the portions of the periphery of the tyre; and
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15. A method of assessing the condition of a tyre on a wheel which is mounted on a vehicle, while the vehicle is moving and the tyre is rotating and moving longitudinally along a path of movement over a base, the periphery of the tyre having tread portions separated by tread gaps;
- in which the method comprises using an imaging device to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution;
there being a plurality of light sources spaced longitudinally, which respectively illuminate different portions of the periphery of the tyre as the tyre moves; and
the images are analysed to determine the depth of the tread gaps;
whereineach light source directs light at an acute angle to the path of movement of the tyre;
when a light source is activated to illuminate a portion of the periphery of the tyre, the light source causes shadows to be cast in the tread gaps between tread portions;
the imaging device is operated to collect an image of at least part of the illuminated portion of the periphery of the tyre; and
the image is analysed by data processing apparatus which determines the extent of the shadow in a tread gap so as to provide an indication of the depth of the tread gap; and
wherein a control system activates the light sources sequentially whilst the tyre moves along said path of movement, so that the light sources do not interfere with each other in such a way as to remove or diminish the shadows cast in the tread gaps between tread portions.
- in which the method comprises using an imaging device to capture images of a plurality of different portions of the periphery of the tyre whilst the tyre completes at least a major part of a complete revolution;
Specification