By Kieron Seth, Seaco Wei & Isaac Chen, Lumens
April 08, 2022 211
Enable Lumens AI-Enable Human Face AutoFocus System (Smart AF), your camera can always keep the subject in sharp focus and get the perfect focus every time.
A camera jumping in and out of focus is simply unwatchable for the audience. It's distracting, irritating and quite literally a turn off.
It's usually caused by poor autofocus. It is particularly challenging for a camera to focus on a human face, especially against a busy foreground and complex background. For example, in a house of worship, the speaker may be surrounded by candles, paintings, statues, and ornate pillars. At a product launch, video walls are often used as a backdrop, featuring motion graphics and animated text. Both scenarios are an issue for standard autofocus systems, with the camera struggling to focus consistently on the subject.
House of Worship
Product Launch Event
A traditional autofocus (AF) system detects the distance of the subject from the camera and automatically adjusts the focal distance of the lens to keep the subject sharp in the photo. If there are many subjects at the shot, three major factors determine how autofocus chooses the focal point- high contrast subject, subject with a sharp edge, and light level. A human face is typically low resolution and is uniform in colour (low contrast). This makes a face difficult to pick out against a high contrast, cluttered background.
Focus on the blackboard
With manned camera positions, the operator can disable the autofocus function and manually adjust the lens. With multiple robotic PTZ cameras either running automatically, or all controlled by a single operator, manual focusing is not practical. A different approach is required.
Enter the"Smart AF" function. Developed by Lumens ProAV Lab, the Smart AF function intelligently identifies facial characteristics, such as eyes, nose, and mouth. The system has been trained on a database of millions of human faces using AI deep learning algorithms. As a result, Smart AF can focus quickly and accurately, even in complex environments. When activated, Smart AF mode prioritizes the human face for autofocus to keep the subject's face perfectly sharp.
Let's see Smart AF in action on Lumens VC-A71P. In picture, when Smart AF is on, the camera focuses exclusively on the face; when deactivated, the camera will focus on the blackboard, or jump in and out of focus.