In October, Google unveiled its latest Pixel 4/ Pixel 4 XL smartphone. It features a 90Hz high refresh rate display, a rear dual camera, and new technology for faster face unlocking and gesture recognition. For those who focus on photo-taking, the introduction of the Night Sight night photography feature provides an impressive astronomical photography experience. If you’re interested in the technical details behind it, the search giant has revealed more in its blog.
(From: Google, via Neowin)
In the article, Google details the Night Sight features of the Pixel 4 smart machine and the technical challenges it faces during build.”
Engineers explain ediths in all aspects of shooting low-light sky images, including exposure time, fixed dark currents, and thermal pixels to help with scene composition, autofocus, and proper handling of sky images in dark environments.
Exposure is one of many challenges in low-light photography. The light that enters the camera sensor determines the brightness of the image. To do this, the camera requires longer exposure times, but this can easily lead to motion blur or star-track in the night sky.
Imagine the marks left in the photo of the taillights of a car on the road at night, the camera that inadvertently moves, and the slight shift in the light. The motion of the star also leaves a mark on the image.
To do this, the Pixel team overcame this problem by taking 15 frames of images in a short exposure time of 16 seconds. The post also details other interesting aspects, such as efforts to reduce hot pixels.
Small bright spots may appear on images taken in low-light environments. With machine learning and trained convolutional neural networks to identify the sky in an image, the Pixel camera app can precisely process it to avoid over-bright skies.
The importance of this work is that the overexposed night sky can cause the photos to look like they were taken during the day. With proper processing, not only can the contrast of the image be improved, but the image can be reduced by performing “sky-specific noise reduction”.
Finally, the Pixel team has some interesting technical tips for interested friends to enhance the night shooting experience for devices such as the Pixel 3, Pixel 3a, and Pixel 4.