How to add variables as strings in an image .JPG, I should do this before creating the file or after?

[LuizFelipe]

Hello everyone,

I have a VI that makes the acquisition of ultrasound images and save frames using "Write to JPEG FILE.vi". The problem is I need to add information (variables such as string and numeric) in these frames.

Here is my VI, it uses a DLL to process the image, output_bilinear is an array that is linearized through another dll (smallest) to enter (output_bilinear_vector 2) the "Write to JPEG FILE.vi"

 

What should I do, enter this information before saving the JPEG file (by some how editing the matrix) or should I edit the JPEG after create(using some image editor)?

Please help.

Thanks

[Andrey_Dmitriev]

Unfortunately you can't do this so easy...

What you can do is following:

- if you using Vision Toolkit, save data to PNG. There are some functions available for writing your custom data to PNG.

- learn how to store user data in jpeg. For example, EXIF data stored in jped as custom data. Search in internet how it organized.

- simply add your data directly at the end of JPEG file. As far, as I know, JPEG file have postfix, so, may be your info will be just ignored by common programs, but you will be read this info back (not checked how it works - just try it).

Andrey.

[LuizFelipe]

unfortunately I do not have the vision toolkit, but with it, as would be done?

the other two options, the information would not be visible in the image?
I need this information to be recorded and visible in the images, like a date and hour at a photo.

thank-you

[Andrey_Dmitriev]

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LuizFelipe wrote:

unfortunately I do not have the vision toolkit, but with it, as would be done?

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Yes, but not with JPEG. In PNG format - yes.

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LuizFelipe wrote:

the other two options, the information would not be visible in the image?

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The information will be invisible.

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LuizFelipe wrote:

I need this information to be recorded and visible in the images, like a date and hour at a photo.

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In case if information should be visible, then you should add this info as overlay. Also I will not recommend to use JPEG format in this case, because you will get poor quality of such overlay due to loss compression.

Andrey.

[LuizFelipe]

Ok, has no problem using PNG instead of JPEG.

But how do I  add this info as overlay? I need the vision toolkit for that?

thanks

[Andrey_Dmitriev]

With Vision Toolkit you will be able to create and store non-destructive overlay and custom data in single PNG file. Search forum for "IMAQ Overlay" - you will found some links. Also Vision toolkit delivered with good examples. But it will be pretty expencive solution.

Probably something linke this will meet your requirements:

 

Andrey.