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US 12,754,297 B2Granted
Time-of-flight sensor and method for adjusting an exposure time of such a sensor
AssigneesSTMicroelectronics France, STMicroelectronics (Grenoble 2) SAS
InventorsJeremie Teyssier, Antoine Drouot, Thibault Augey, Valerie Pena-Laroche
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Abstract
An indirect time-of-flight measurement sensor includes a photosensitive pixel array configured to acquire a succession of images of a scene during a given exposure time. The sensor includes a control unit configured to control the acquisition of the succession of images by the pixel array and to define an exposure time for this acquisition based on a pixel saturation rate of the array, distances between the sensor and elements of the scene, and a standard deviation of the distances between the sensor and the elements of the scene.
Claims12
An indirect time-of-flight measurement sensor, comprising:
- a photosensitive pixel array configured to acquire a succession of images of a scene during a given exposure time;
- and
- a control unit configured to control an acquisition of a succession of images by the pixel array and to define an exposure time for the acquisition according to a pixel saturation rate of the array, distances between the sensor and elements of the scene, and a standard deviation of the distances between the sensor and the elements of the scene, wherein the control unit is configured to define the exposure time for the acquisition from the pixel saturation rate of the array and a precision of the sensor corresponding to a ratio between the distances between the sensor and elements of the scene and the standard deviation of the distances between the sensor and the elements of the scene, wherein the control unit is configured to compare the pixel saturation rate with a saturation rate threshold, and to:
- if the pixel saturation rate is greater than the saturation rate threshold, reduce the exposure time,
- otherwise compare the precision to a precision threshold, and
- if the precision is greater than the precision threshold, reduce the exposure time,
- otherwise, increase the exposure time.
4 more elements
A method, comprising:
- acquiring a succession of images of a scene with pixels of a photosensitive pixel array of an indirect time-of-flight measurement sensor during a given exposure time;
- and
- defining the exposure time for the acquisition based on a pixel saturation rate of the array, distances between the sensor and elements of the scene, and a standard deviation of the distances between the sensor and the elements of the scene;
- defining the exposure time for the acquisition based on the pixel saturation rate of the array and a precision of the sensor corresponding to a ratio between the distances between the sensor and elements of the scene and the standard deviation of the distances between the sensor and the elements of the scene;
- comparing the pixel saturation rate with a saturation rate threshold, and
- if the pixel saturation rate is greater than the saturation rate threshold, reducing the exposure time,
- otherwise comparing the precision with a precision threshold, and
- if the precision is greater than the precision threshold, reducing the exposure time,
- otherwise, increasing the exposure time.
6 more elements
A method, comprising:
- sensing, for each of a plurality of objects, a distance between a sensor and the object;
- calculating a standard deviation of the distances;
- selecting, with a control unit of the sensor, an exposure time based on a pixel saturation rate of a photosensitive pixel array of the sensor and on the standard deviation of the distance;
- acquiring, with a photosensitive pixel array of a sensor, a plurality of images of the objects with the selected exposure time;
- selecting the exposure time based on a precision of the sensor, wherein the precision of the sensor corresponds to a ratio between the distances and the standard deviation of the distances;
- comparing, with the control unit, the pixel saturation rate with a saturation rate threshold;
- reducing the exposure time if the pixel saturation rate is greater than the saturation rate threshold;
- and,
- comparing the precision to a precision threshold if the pixel saturation rate is less than the saturation rate threshold;
- reducing the exposure time if the precision is greater than the precision threshold;
- and
- increasing the exposure time if the precision is less than the precision threshold.
9 more elements
Dependencies are inferred from the claim text.