Invisiletter API provides images which are embedded the digital watermark as well as InvisiLetter. The digital watermark can be extracted by using InvisiLetter and InvisiReader.
How to use this API
Send the URL – http://samurai-apps.com/invisiletterapi/embed.cgi – containing query parameters.
signimage : The URL of a sign image．This image should be JPEG/PNG format and grayscale (recommended 1bit) image under 512KB.
origimage : The URL of an original image．This image should be JPEG/PNG format and color image under 512KB.
strength : Number within the range from 1 to 255. Default is 60. If you specify small number, the quality of the embedded image is better, but the quality of extracted secret image is low.
requesturl : Specify “true” or “false”. Default is “false”. If you specify “true”, you can get an XML including the URI of the embedded image. Else if you specify “false”, you can get the embedded image itself.
If you specify “requesturl=true”, you can get an XML like below.
(URL of the embedded image)
If there are some errors, you will get an XML including error code like below.
errorcode 901 : the URL of signimage is invalid or too large to read.
errorcode 902 : the URL of origimage is invalid or too large to read.
errorcode 903 : origimage is not PNG/JPEG format.
errorcode 904 : signimage is not PNG/JPEG format.
(Example of returning errorcode 901 and 902 at the same time)
901 A signature image cannot be read. 902 An original image cannot be read.
Example of URL
About embedded images
The origimage will be resized 480×320 or less. In the resize of origimage, the aspect ratio (fineness ratio) is maintained. The signimage will be resized to the same size as resized origimage. In the resize of signimage, the aspect ratio (fineness ratio) is NOT maintained. The embedded image becomes the same size as the resized origimage.
For example, when size of origimage is 1024×1024 and size of signimage is 800×600, then origimage and signimage are resized 320×320 and you can get the 320×320 embedded image.
Format of the embedded image is full color PNG.
origimage, signimage and embedded images’ name are changed at random and it is preserved for a certain period in the server. Even if these images leak due to an unexpected accident, we cannot assume the responsibility at all. Use on acknowledging it and EULA.
It limits it to the non-commercial use. Please contact us when you use this to the commercial use.
End User Licence Agreement
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