A variable-color region (106) of an information-presentation structure extends to an exposed surface (102) at a surface zone (112) and normally appears along it as a principal color. An impact-dependent portion (138) of the variable-color region responds to an object (104) impacting the zone at an object-contact area (116) by temporarily appearing along a print area (118) of the zone as generic changed color materially different from the principal color. The print area closely matches the object-contact area in size, shape, and location. The colors are chosen to accommodate persons who are color blind. One of the principal and changed colors is usually restricted from being any color from green to red in the visible light spectrum or any color having a non-insignificant component of any color from green to red in the light spectrum for accommodating persons having the predominant red-green color blindness.

A coating, for example a piezochromic coating, can adhere to a pickleball court. The coating can mark a pickleball bounce point during pickleball play on the pickleball court. When a pickleball bounces from a coated surface of the pickleball court, the pickleball can produce a mark on or in the coating at the bounce point. The mark can provide a visible indication of location of the bounce point that informs whether the bounce point was in an in-bounds or an out-of-bounds area of the pickleball court. The coating can thus help players and/or referees determine who prevailed in a volley or won a point during a pickleball game.

A let detection system includes a sensor including an accelerometer attached to a tennis net. The sensor is in wireless communication with an umpire device able to send a message to the sensor, wherein the message causes the sensor to calibrate and begin monitoring for a let. The sensor determines a three-dimensional (3D) vector representing the gravity acting on the sensor as a baseline. When the sensor detects vertical acceleration of the net relative to the baseline and the vertical motion is above a preset threshold, the sensor automatically transmits a let notification message to the umpire device.

A variable-color region (106) of an information-presentation structure extends to an exposed surface (102) at a surface zone (112) and normally appears along it as a principal color. An impact-dependent portion (138) of the variable-color region responds to an object (104) impacting the zone at an object-contact area (116) by providing an impact signal if the impact meets threshold impact criteria. The impact signal identifies an expected location of a print area (118) in the zone and supplemental impact information for the impact. Responsive to the impact signal, a controller (702) determines whether the supplemental impact information meets supplemental impact criteria and, if so, provides an initiation signal. The impact-dependent portion responds to the initiation signal, if provided, by temporarily appearing along the print area as changed color materially different from the principal color. The print area closely matches the object-contact area in size, shape, and location.

A variable-color region (106) of an information-presentation structure extends to an exposed surface (102) at a surface zone (112) and normally appears along it as a principal color. An impact-dependent portion (138) of the variable-color region responds to an object (104) impacting the zone at an object-contact area (116) by temporarily appearing along a closely matching print area (118) of the zone as changed color materially different from the principal color if the impact meets threshold impact criteria. Object-tracking apparatus (808) tracks movement of the object over the surface and provides an image-causing tracking impact signal when the object impacts the zone according to the tracking. An image-generating system (802, 842, 1152, or 1182) responds to at least the impact signal by generating a print-area vicinity image consisting of an image of the print area and adjacent area of the surface.

The present invention relates to an apparatus, method and computer program for collecting and processing digital information by computer vision and/or tracking as well as observing specific events during sports, in particular during the practice of racket sports, comprising: at least one camera pair for obtaining real image-related information in sports-related stereo, processor for processing the actual image-related information from the at least one camera, memory space containing stored comparison data for typical actions of a fictitious athlete and for typical movements and positions of a fictitious ball, the camera, processor and memory space all to each other for both storage and retrieval of digital information, the processor comparing the actual image-related information from the at least one camera with the corresponding stored comparison data from the memory space and categorizing the work image-related information.

The present invention relates to an apparatus, method and computer program for collecting and processing digital information by computer vision and/or tracking as well as observing specific events during sports, in particular during the practice of racket sports, comprising: at least one camera pair for obtaining real image-related information in sports-related stereo, processor for processing the actual image-related information from the at least one camera, memory space containing stored comparison data for typical actions of a fictitious athlete and for typical movements and positions of a fictitious ball, the camera, processor and memory space all to each other for both storage and retrieval of digital information, the processor comparing the actual image-related information from the at least one camera with the corresponding stored comparison data from the memory space and categorizing the work image-related information.