Focus Peaking False Color Overlay for Depth of Field Indication

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Solution Overview

Problem

Current on-set video and film production tools lack precise focus peaking overlays for high-resolution cameras, making it difficult to determine the point of sharpest focus and depth-of-field, especially on small viewfinder monitors.

Innovation Solution

A method and apparatus using a waveform monitor to generate a real-time focus peaking false-color overlay by measuring frequency information from the camera image, selecting high-frequency values, and modifying pixels to indicate both the point of sharpest focus and the range of depth-of-field, using color markers to highlight focused areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-resolution cameras (4K pixels or more) are used to improve image quality, then image quality is improved, but it becomes more difficult to set focus precisely without using a large reference monitor

Engineering Contradiction:
Improvefocus precisionVSAvoidfocus setting difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies false color overlays to the camera image to visually indicate focus accuracy. Different colors represent different focus states, allowing operators to precisely adjust focus by observing the color-coded feedback on the small viewfinder monitor without needing a large reference monitor.

Inventive Principle:
Principle #32Color changes

2Area of stationary object

If small viewfinder-size monitors are used to reduce device size and portability issues, then device portability is improved, but the ability to indicate focused region accurately is reduced

Engineering Contradiction:
Improvemonitor sizeVSAvoidfocus indication accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

By overlaying false colors directly on the small viewfinder monitor display, the system compensates for the limited screen real estate. The color-coded focus indicators provide precise focus information that would otherwise require a much larger monitor to display effectively.

Inventive Principle:
Principle #32Color changes

3Loss of information

If traditional focus peaking overlays are used to indicate focused region, then some focus information is provided, but the information is insufficient for precise focus adjustment

Engineering Contradiction:
Improvefocus information completenessVSAvoidfocus adjustment precision
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent divides the focus information into multiple segmented indicators: a first false color indicates the in-focus region while a second different false color indicates the depth of field range. This segmentation provides comprehensive focus information that enables precise focus adjustment by distinguishing between the sharply focused area and the acceptable focus range.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2928179B1Depth of field indication using focus-peaking picture markers
Publication Date: 2019.06.12 TEKTRONIX INC
  • EP2928179B1 patent drawingFigure 1
  • EP2928179B1 patent drawingFigure 2
  • EP2928179B1 patent drawingFigure 3

AI summary

A waveform monitor for generating a modified image from an original image includes a measuring system to select luminance frequency values of the original image that are above a first and a second threshold. A modifier changes selected pixels of the original image that fall above the first and second thresholds. In some embodiments these changed pixels are given a false color as color markers to indicate DOF and areas of sharpest focus of the original image. Methods of modifying images in this manner are also described.