Abstract

A charge-sensitive amplifier configured to receive an input charge signal from a radiation sensor includes a high-open-loop- voltage gain amplification stage including at least one of an operational amplifier and/or operational transconductance amplifier, a capacitive network electrically coupled between an input and an output of the high-open-loop- voltage gain amplification stage, and an active feedback circuit network electrically coupled between the input and the output of the high-open-loop-voltage gain amplification stage. The capacitive network provides integration of the input charge signal and conversion of the input charge signal to a voltage available at an output of the charge-sensitive amplifier.

IPC Classes  ?

• H03F 3/45 - Differential amplifiers
• H03F 3/16 - Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only with field-effect devices

Abstract

The method for restricting access to sensitive contents of digital images using the digital watermarking technique for encoding and decoding sensitive contents of images is characterized in that the sensitive contents of an image are obscured, and the information necessary for the high quality reconstruction is encoded in the insensitive area of the transmitted image by modification of the DCT spectrum coefficients. The information concerning the obscured contents is retained by means of transform coefficients and processed independently. Noise with statistics identical to that of the digital watermark is inserted into the image after decoding. The system contains encoding unit including acquisition module connected with sensitive contents encoding module through sensitive patterns automatic detection module with attached memory buffer. Also, acquisition module is connected directly with sensitive contents encoding module and with compression module. In the decoding unit, stream decoding module is connected with image sensitive contents decoding module.

IPC Classes  ?

• G06K 9/00 - Methods or arrangements for reading or recognising printed or written characters or for recognising patterns, e.g. fingerprints
• B42D 15/00 - Printed matter of special format or style not otherwise provided for
• H04N 1/40 - Picture signal circuits
• G09C 3/00 - Typewriters for ciphering or deciphering cryptographic text
• H04L 9/32 - Arrangements for secret or secure communicationsNetwork security protocols including means for verifying the identity or authority of a user of the system