Can't access data using " .DateTime " string

hey, I'm taking image processsing ccourse from coursera by MATHWORKS. but there is a problem in accessing date and time of a picture in matlab using following given method in this course. please help in this query so that i can continue my course.

[Stephen23]

What fields does METADATA contain? How did you create METADATA?

[Laiba]

metadata is created as shown below..... following are the fields that metadata contains.

Answer 1

[Star Strider]

Perhaps this —

imshow(imread('peppers.png'))

metadata = imfinfo('peppers.png')

metadata = struct with fields:
                  Filename: '/MATLAB/toolbox/matlab/matlab_images/png/peppers.png'
               FileModDate: '13-Jul-2023 20:26:13'
                  FileSize: 287677
                    Format: 'png'
             FormatVersion: []

                     Width: 512
                    Height: 384
                  BitDepth: 24
                 ColorType: 'truecolor'
           FormatSignature: [137 80 78 71 13 10 26 10]
                  Colormap: []

                 Histogram: []

             InterlaceType: 'none'
              Transparency: 'none'
    SimpleTransparencyData: []

           BackgroundColor: []

           RenderingIntent: []

            Chromaticities: []

                     Gamma: []

               XResolution: []

               YResolution: []

            ResolutionUnit: []

                   XOffset: []

                   YOffset: []

                OffsetUnit: []

           SignificantBits: []

              ImageModTime: '16 Jul 2002 16:46:41 +0000'
                     Title: []

                    Author: []

               Description: 'Zesty peppers'
                 Copyright: 'Copyright The MathWorks, Inc.'
              CreationTime: []

                  Software: []

                Disclaimer: []

                   Warning: []

                    Source: []

                   Comment: []

                 OtherText: []

         AutoOrientedWidth: 512
        AutoOrientedHeight: 384

DateTime = datetime(metadata.FileModDate)

DateTime = datetime
   13-Jul-2023 20:26:13

.

[Laiba]

Thank you so much for answering, this solved above problem but there is one more problem now...

can you also tell how to solve this problem now?

[Star Strider]

I cannot find anything with respect to the camera in the imfinfo properties.

imshow(imread('peppers.png'))

metadata = imfinfo('peppers.png')

metadata = struct with fields:
                  Filename: '/MATLAB/toolbox/matlab/matlab_images/png/peppers.png'
               FileModDate: '13-Jul-2023 20:26:13'
                  FileSize: 287677
                    Format: 'png'
             FormatVersion: []

                     Width: 512
                    Height: 384
                  BitDepth: 24
                 ColorType: 'truecolor'
           FormatSignature: [137 80 78 71 13 10 26 10]
                  Colormap: []

                 Histogram: []

             InterlaceType: 'none'
              Transparency: 'none'
    SimpleTransparencyData: []

           BackgroundColor: []

           RenderingIntent: []

            Chromaticities: []

                     Gamma: []

               XResolution: []

               YResolution: []

            ResolutionUnit: []

                   XOffset: []

                   YOffset: []

                OffsetUnit: []

           SignificantBits: []

              ImageModTime: '16 Jul 2002 16:46:41 +0000'
                     Title: []

                    Author: []

               Description: 'Zesty peppers'
                 Copyright: 'Copyright The MathWorks, Inc.'
              CreationTime: []

                  Software: []

                Disclaimer: []

                   Warning: []

                    Source: []

                   Comment: []

                 OtherText: []

         AutoOrientedWidth: 512
        AutoOrientedHeight: 384

DateTime = datetime(metadata.FileModDate)

DateTime = datetime
   13-Jul-2023 20:26:13

Source = metadata.Source

Source =

     []

Here, the Source field is simply empty. See if that works with your image.

.

[Laiba]

thankyou you solved my problem

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.

[Walter Roberson]

According to the documentation for imfinfo()

• DNG, JPEG, and TIFF only — If filename contains Exif tags, then info might include DigitalCamera or GPSInfo (global positioning system information) fields.

So this applies only to .dng, .jpg, .jpeg, .tif, and .tiff files, and only if the file includes EXIF tags, and even then only if the EXIF tags happen to include DigitalCamera or GPSInfo . If any of these three conditions are not satisfied, the DigitalCamera field will simply not be present. It will not "be present but empty" in such cases: it will literally not be present in such cases.

I was not able to find any case that potentially included a DateTime field.

[Star Strider]

@Walter Roberson — Thank you for the clarification!