Camera Electronic Viewfinder AF Target Display Control
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Solution Overview
Problem
Cameras with both optical and electronic finders experience delays in displaying AF target images, leading to user discomfort and incorrect focus judgments due to the time needed for readout from solid-state electronic image sensing devices, especially when the subject or camera is moving.
Innovation Solution
A camera system with a lens barrel, setting device, finder unit, shutter device, solid-state electronic image sensing device, display unit, and display control device that allows for quick display of AF target images by controlling the display to coincide or offset with the optical image based on focus status, using a deflecting unit to introduce AF target images to the eyepiece window and adjusting the display unit to correct for parallax.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the double-image coincidence system is applied to a camera with both optical and electronic finders, then focusing guidance can be provided, but the time needed to display the AF target image is delayed due to readout time from the solid-state electronic image sensing device
Solution Approach 1:
The patent divides the image sensor data into two processing paths: a full readout for the electronic viewfinder display and a partial/rapid readout for the AF target area. By segmenting the data processing, the system provides focus guidance without requiring complete image readout, thereby reducing display delay while maintaining focus accuracy.
Solution Approach 2:
The system performs preliminary processing of the AF target area data separately from the complete image readout. By preparing the focus determination data in advance through selective reading or interpolation, the system reduces the time required to display the AF target image while the complete image is being read out for the electronic viewfinder.
2Adaptability or versatility
If the complete image is read out from the solid-state electronic image sensing device for display, then the electronic viewfinder shows the captured image, but the AF target image display is delayed
Solution Approach 1:
The patent segments the image data processing by separating the AF target area extraction from the complete image readout. This allows the system to provide focus guidance using only the necessary portion of the image data, while the complete image is read out for the electronic viewfinder, thereby reducing the time delay without compromising electronic viewfinder functionality.
3Ease of operation
If the optical image and AF target image are displayed simultaneously, then focusing can be guided, but the images may not coincide if the subject or camera is moving due to readout delay
Solution Approach 1:
The system performs preliminary processing and matching of the AF target image based on the optical image position before display. By calculating the expected position of the AF target relative to the optical image in advance and applying appropriate transformations, the system ensures that the images coincide accurately even during subject or camera movement, maintaining reliable focusing guidance.
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
Enables rapid and accurate display of AF target images, ensuring that the optical and electronic images coincide when in focus, reducing user discomfort and improving focus accuracy even during subject or camera movement.
Implementation Method 1
a deflecting unit, which is provided between the objective window and the eyepiece window, for introducing the AF target image or image of the subject, which is being displayed on the display screen of the display unit, to the eyepiece window
Implementation Method 2
a solid-state electronic image sensing device responsive to setting of the electronic viewfinder function by the setting device for capturing the image of the subject formed by the lens barrel and outputting subject-image data representing the captured image of the subject
Data Source
AI summary
An image of subject formed optically is obtained by the finder unit. The subject is imaged electronically by an image sensing device, and a video signal, which represents an image within an autofocus target area inside the image of the subject of the subject obtained, is read out of the image sensing device. The image represented by the video signal is displayed on the display screen of a liquid crystal device which constitutes an electronic viewfinder. Looking through the finder unit, a user sees an image obtained by superimposing the image, which is displayed on the display screen, upon the optical image of the subject. If correct focusing is achieved, the optical image of the subject and the image coincide. Since a video representing a portion of the image of the subject is read out of the image sensing device, the image is displayed without delay.