According to a first aspect of the invention, there is provided a method of deriving information from an optically readable security element, comprising: optically reading the optically readable security element, the optically readable security element comprising at least one optically readable structure, optically readable in response to excitation of the optically readable structure; the reading comprising determining data indicative of an optical property of the optically readable security element using first emission electromagnetic radiation, emitted in response to excitation of the optically readable structure; the deriving information further comprising using the determined data indicative of an optical property, in combination with a temporal excitation-emission relationship related to the optically readable structure, to derive the information.

According to a first aspect of the invention, there is provided a method of deriving information from an optically readable security element, comprising: optically reading the optically readable security element, the optically readable security element comprising at least one optically readable structure, optically readable in response to excitation of the optically readable structure; the reading comprising determining data indicative of an optical property of the optically readable security element using first emission electromagnetic radiation, emitted in response to excitation of the optically readable structure; the deriving information further comprising using the determined data indicative of an optical property, in combination with a temporal excitation-emission relationship related to the optically readable structure, to derive the information.

The optical sensor of the present disclosure includes: a light source configured to emit irradiation light to a target; a light receiver configured to receive a first incident light, a second incident light, and a third incident light travelling from the target and having different wavelength bands; and a controller configured to control the light source. The light receiver includes: a first light-receiving element configured to receive the first incident light and the second incident light and not to receive the third incident light; and a second light-receiving element configured to receive the third incident light and to receive neither the first incident light nor the second incident light.

The optical sensor of the present disclosure includes: a light source configured to emit irradiation light to a target; a light receiver configured to receive a first incident light, a second incident light, and a third incident light travelling from the target and having different wavelength bands; and a controller configured to control the light source. The light receiver includes: a first light-receiving element configured to receive the first incident light and the second incident light and not to receive the third incident light; and a second light-receiving element configured to receive the third incident light and to receive neither the first incident light nor the second incident light.

A method of obtaining a plurality of infrared images of a banknote that involves simultaneously illuminating the banknote with infrared light at a first wavelength and infrared light at a second wavelength, capturing an image of the banknote with an RGB camera, obtaining from both a first output channel signal and a second output channel signal of the RGB camera sensor where the intensity distribution of the infrared light at the first wavelength and the intensity distribution of the infrared light at the second wavelength uses a first calibration coefficient and a second calibration coefficient of the RGB camera sensor, producing separate infrared images of the banknote at the first wavelength and the second wavelength from the respective intensity distributions.

A method of obtaining a plurality of infrared images of a banknote that involves simultaneously illuminating the banknote with infrared light at a first wavelength and infrared light at a second wavelength, capturing an image of the banknote with an RGB camera, obtaining from both a first output channel signal and a second output channel signal of the RGB camera sensor where the intensity distribution of the infrared light at the first wavelength and the intensity distribution of the infrared light at the second wavelength uses a first calibration coefficient and a second calibration coefficient of the RGB camera sensor, producing separate infrared images of the banknote at the first wavelength and the second wavelength from the respective intensity distributions.

Provided is an image sensor lighting unit including at least one light guide extending in a main scanning direction; a first light source group facing a first end surface of at least two end surfaces of the at least one light guide in the main scanning direction; and a second light source group facing a second end surface of the at least two end surfaces. The first light source group includes a first light source that emits light having a predetermined wavelength band. The second light source group includes a second light source that emits light having the wavelength band. An X-coordinate of the first light source in a corresponding XY-coordinate system is equal in absolute value to an X-coordinate of the second light source in a corresponding XY-coordinate system, with the at least one light guide viewed from the first end surface side in the main scanning direction.

Device for detecting reactive luminescent particles embedded in a substrate or surface having an infrared or ultraviolet illuminator; a near-infrared photodiode sensor; a dark chamber, inside which the illuminator and photodiode sensor are mounted; a logarithm amplifier; an electronic data processor configured to detect the reactive luminescent particles by carrying out the steps of: illuminating the substrate or surface with the illuminator; acquiring the amplified linearized signal captured by the photodiode sensor; detecting the presence of luminescent particles in the substrate or surface from the linearized decay of the acquired signal. A further near-infrared photodiode sensor, a further logarithm amplifier, and a differentiator for obtaining a difference between amplified signals received by each photodiode sensor can be utilized.

An optical sensor of the present disclosure detects light reflected by a transported sheet and/or light transmitted through the sheet as well as light emitted from the sheet. The optical sensor includes: a light source configured to irradiate a sheet with excitation light and detection light; a controller configured to keep the light source turned off during each of light-off periods after the emission of the excitation light; and a light receiver configured to receive light resulting from reflection of the detection light by a sheet and/or light resulting from transmission of the detection light through the sheet in each of the light-on periods and receive phosphorescence emitted from the sheet in each of the light-off periods. The controller is configured to generate data of one pixel by summing up output values based on respective phosphorescence components received by the light receiver in each of the light-off periods.

An optical sensor of the present disclosure detects light reflected by a transported sheet and/or light transmitted through the sheet as well as light emitted from the sheet. The optical sensor includes: a light source configured to irradiate a sheet with excitation light and detection light; a controller configured to keep the light source turned off during each of light-off periods after the emission of the excitation light; and a light receiver configured to receive light resulting from reflection of the detection light by a sheet and/or light resulting from transmission of the detection light through the sheet in each of the light-on periods and receive phosphorescence emitted from the sheet in each of the light-off periods. The controller is configured to generate data of one pixel by summing up output values based on respective phosphorescence components received by the light receiver in each of the light-off periods.