Giving Historical Photographs a New Perspective: Introducing Camera Orientation Parameters as New Metadata in a Large-Scale 4D Application

Round 1

Reviewer 1 Report

An interesting and valuable paper. Strongly urge it to be published. I have some minor editorial questions and suggestions below.

Please note the difficulties encountered with the application. 

With respect to metadata, the authors should mention/refer to the Archaeology Data Services Guides to Good Practice. This two-decade-old set of guides proposes metadata for photogrammetry as well as other data acquisition methods. https://archaeologydataservice.ac.uk/help-guidance/guides-to-good-practice/  They are now a bit dated but as the first such efforts should be noted.

I am curious (and suspect other readers maybe as well) as to the impact of the common practice in professional architectural photography to utilize tilt-shift lenses. Historically these were common to correct for convergence and other optical effects. Would the use of such a lens impact the process described? It would seem that the assumption that the principal point (line 247) is in the image center might not apply?

Line 42 the wording “ .. excluding the detailed displays of. e.g.., statues or pillars. “ is unclear. It should be reworded I am not clear what the authors mean. Is it that detailed objects are excluded or that specific architectural details are excluded or … ?

Line 47. I believe the sentence would be clearer (If I correctly understood the meaning) if it was reworded to “Due to the possible variation in historic image quality, the conventionally used software Agisoft Metashape fails to register a large number of these types of images.

Line 56 “Signalized by metadata” – the wording is unclear … do the authors mean “as indicated by metadata”

Line 141. Suggesting adding the WGS epoch and information on the level of precision used in the lat/lon values

Line 156. I am curious about the use of the UTM system. Scale factors vary significantly within a UTM zone depending on location. In the US state plane systems (or even local coordinate systems) are used for high-precision urban mapping. Not a critical point but might be useful for authors to note the issue. I do note that deviation values are 7.25 m (line 462) so these geodetic issues may not be relevant.

Line 345 suggest change wording to “..a minor issue when the database is known.”

Line 378. I attempted to follow the instructions on accessing the imagery. On A Mac (Mac Studio with 200 MB Internet access)  and Chrome (current build) the page was unresponsive. I switched to a Safari and was able to access the Semperoper – though there was notable lag while the 3D view and photos loaded. Once loaded the application worked as described. When attempting to use the time slider the years became overwritten and unclear how to select dates.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript presented methodology allows the automatic determination of camera parameters for historical photographs. All derived camera information is  efficiently stored in the database of the presented 4D application to allow the addition of new data at  the time it is digitized. The study is very significant to digitize the historical photographs in archives. There are a few problems need to be further clear : 1) how efficient is this method?  2) What is its scope of application? in particular, what are the requirements for the reference images of a landmarks.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The revised version of the paper has basically met the publication requirements and is agreed to be published. However, it is suggested that the abstract section should be further optimized to highlight the key points of this paper, such as specific methods, characteristics and effects in this study.

Author Response

Please see the attachment.

Author Response File: Author Response.docx