Cameras and image sensors are devices used to capture images of a scene. Some cameras (e.g., film cameras) chemically capture an image on film. Other cameras (e.g., digital cameras) electrically capture image data (e.g., using a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) sensors). Images captured by cameras can be analyzed to determine their contents. For example, a processor may execute a machine-learning algorithm in order to identify objects in a scene based on a library of previously classified objects that includes objects' shapes, colors, sizes, etc. (e.g., such a machine-learning algorithm can be applied in computer vision in robotics or other applications).
Cameras can have a variety of features that can distinguish one camera from another. For example, cameras and/or images captured by cameras may be identified by values such as aperture size, f-number, exposure duration/shutter speed, depth of field, focal length, International Organization for Standardization (ISO) sensitivity (or gain), pixel size, sensor resolution, exposure distance, etc. These features may be based on the lens, the image sensor, and/or additional facets of the camera. Further, these features may also be adjustable within a single camera (e.g., the aperture of a lens on a camera can be adjusted between photographs).
Some applications benefit from cameras that have a wide dynamic range. For example, the luminance of the brightest object (e.g., the sun at the middle of the day or emergency vehicle lights) and the luminance of the darkest object (e.g., a black cat in the middle of the night) may vary by orders of magnitude from one another (e.g., range from 105 nits to 10−2 nits, i.e., 105 cd/m2 to 10−2 cd/m2). Being able to capture images at both ends of such a wide dynamic range may be important for navigation and object detection and avoidance in autonomous vehicles, for example. A wide dynamic range may be difficult to achieve in autonomous vehicle applications because of vehicle motion. For example, if the vehicle is moving at a relatively high velocity, the exposure duration may be kept relatively short to prevent motion blur, thereby limiting the maximum exposure duration. In addition, if a certain range of luminance values is not captured by an image sensor with an adequate exposure setting, colors within images can be distorted (e.g., reds can appear as yellows in saturated captured images when the red channel saturates and starts clipping). Flares, glare, or other forms of aberrant light can also impair the quality of captured images.