Mention must be made of the Amazon phone, dubbed the Fire. Amongst other things, writes Steve Bush, one-handed gestures can be used for scroll, tilt and swivel navigation.
Four front face image sensors and four infra-red LEDs form the physical interface, and inside are a dedicated custom processor, real-time computer vision algorithms, and a graphics rendering engine, said the firm.
Gesture recognition is part of something it has branded 'Dynamic Perspective'.
"Dynamic perspective uses a new sensor system to respond to the way you hold, view, and move Fire, enabling experiences not possible on other smartphones," claimed Amazon, which is providing a dynamic perspective software design kit (SDK).
Image sensing also plays a part in something called Firefly, which auto-recognises web addresses, email addresses, printed phone numbers, QR codes, bar codes, printed text on signs, posters, magazines and business cards. "Make a call, send an email, save as a contact, or go to the website without typing out URLs or email addresses," said the firm.
The phone's hardware includes a 2.2GHz quad-core Qualcomm Snapdragon processor with 2Gbyte of RAM and a choice of 32 or 64Gbyte of flash.
The display is 4.7in (12cm), with an ambient light sensor, and wireless interfaces include: nine bands of LTE, four bands of GSM, five bands of UMTS, 802.11ac (and Wi-Fi channel bonding), NFC, and Bluetooth.
As well as the gesture sensors, there are two conventional cameras: at the rear camera is a back-side-illuminated 13Mpixel sensor with LED flash, a five element f/2.0 lens and optical image stabilization (OIS). While at the front is a 2.1Mpixel camera. Both can record 1080p video.
The US cost, through AT&T, is $199.99 with a 2-year contract for a 32 GB model. A 64 GB model costs $299.99. Without a contract, the phone will cost $649.99.
Pre-orders for the phone begin Wednesday, and the phones will be available starting July 25.