ISO/TS 20490:2024 オートフォーカスのシャープネスとレイテンシーの再現性を測定 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 42, Photography.

Introduction

This document is focusing on measuring the repeatability of the AF latency and the sharpness of the captured images. ISO 15781 specifies how to measure and report the shooting time lag, shutter release time lag, shooting rate and start-up time lag for digital still cameras. This document focuses on combining the autofocus latency with measured sharpness of the captured photos, making it more comprehensive test procedure for evaluating autofocus systems.

This document widens the options for usable test charts from high contrast digitally created charts to natural images and to other test charts and even 3D scenes, challenging the autofocus systems. It also allows measurements to be carried out in variable lighting conditions, and in presence of handshake, challenging the AF system further.

ISO 15781 is mainly focusing on traditional single autofocus solutions actuated by half pressing physical shutter button, widely used with SLR cameras. However, this document can be applied to continuous AF systems, commonly used in mobile camera devices, as well as to single autofocus systems.

This document provides procedures and methods to measure and report the autofocus (AF) repeatability of sharpness and latency of a digital still camera. The data gathered is useful when comparing camera devices with sufficiently similar autofocus solutions and it helps with further investigations into a camera’s autofocus repeatability performance.

The terminology is defined within this document along with describing the test charts, the setup, the methods, the performance metrics and analysis methodology to assess and report on the autofocus repeatability of a camera device. This document covers the test setups, the process, what pictures to capture and the metrics to calculate.

A great camera system should be capable to deliver repeatably sharp images within acceptable and repeatable latency, making the characterization of the AF system very important.

1 Scope

This document is focused on measuring the autofocus (AF) repeatability of sharpness and latency, meaning camera system’s capability to produce sharp images within certain time frame. The scope of document is limited to testing autofocus sharpness and latency repeatability with stationary charts only as testing with moving charts is not covered.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions and abbreviated terms

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

Bibliography