Shortened LED Pre-Flash for Camera White Balance
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Solution Overview
Problem
Conventional camera device flashes emit a long pre-flash that irritates subjects and bystanders, causing them to close their eyes and requiring additional photos and memory space.
Innovation Solution
Implementing a shortened pre-flash duration, which can be less than 400 milliseconds or even zero, to obtain only white balance and auto-exposure measurements, reducing eye irritation and avoiding auto-focus during the pre-flash, especially in sufficient light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a long pre-flash (1-5 seconds) is used for LED flash, then the camera can obtain accurate white balance and exposure measurements, but it causes eye irritation and makes subjects close their eyes
Solution Approach 1:
The patent applies partial action by providing only the necessary duration of pre-flash to obtain white balance and exposure measurements, rather than using a full 1-5 second pre-flash. The pre-flash is limited to a shorter duration (e.g., 100-400 milliseconds) which is sufficient for measurement purposes but too brief to cause significant eye irritation or make subjects close their eyes.
2Measurement precision
If a long pre-flash is used, then measurement data can be obtained, but additional photos must be taken causing loss of time and memory space
Solution Approach 1:
The patent uses partial action by providing a pre-flash duration that is sufficient for obtaining white balance and exposure measurements but too short to cause subjects to close their eyes, thereby eliminating the need for retakes and associated time loss.
Solution Approach 2:
The patent changes the temporal parameter of the pre-flash from 1-5 seconds to a shorter duration (100-400 milliseconds). This parameter change allows the pre-flash to fulfill its measurement function while avoiding the harmful effect of causing subjects to close their eyes, thus preventing the need for additional photos.
3Measurement precision
If a long pre-flash is used, then measurement data can be obtained, but additional memory space is required for storing extra photos
Solution Approach 1:
The patent applies partial action by using a pre-flash duration that is sufficient for obtaining measurement data but too short to cause subjects to close their eyes, thereby preventing the need for additional photos and reducing memory space consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The shortened pre-flash reduces eye irritation and minimizes the need for additional photos, optimizing image capture by using the flash more efficiently in various lighting conditions.
Implementation Method 1
the flash can be irritating to the eyes of one or more people in the picture and can affect the eyes of one or more people near the camera as well. For example, when the flash is being used and a user presses the shutter release of the camera device, the flash emits a pre-flash
Data Source
AI summary
A mobile device comprising a processor, a camera module, and a flash configured to generate at least one of a reduced pre-flash, a standard pre-flash and a flash. The processor, in response to receiving an image capture request, is configured to receive a brightness value and determine a flash status based on a flash setting with the flash status being one of an off mode, on mode, and auto mode. In the event the flash status is one of the on mode and auto mode, determine whether there is sufficient light to capture an image based at least in part on a comparison of the brightness value and a flash threshold. In the event the brightness value is greater than the flash threshold, cause the flash to generate a shortened pre-flash and obtain only a white balance measurement and an auto-exposure measurement during the shortened pre-flash.