Abstract: A drive controller is configured to control an imaging unit so that a subject is imaged at a first exposure mode and imaged at a second exposure mode. A gain controller is configured to set equal to each other luminance amplitudes of a first and second image signals due to the difference in exposure time period of a first luminance signal obtained by imaging the subject in the first exposure mode and a second luminance signal obtained by imaging the subject in the second exposure mode. A determination unit is configured to detect a change between each frame of high-frequency components included in the first and second luminance signals whose luminance amplitudes are set equal to each other and to determine that the image of a surveillance area has changed when an amount of a detected change is equal to or larger than a predetermined value.

Abstract: Each pixel receives a digital picture data having a multi-gradation data. A line composed of printing pixels having a thickness difference of multi-gradations is obtained on a recording paper by controlling whether or not there exist ink transcription by each gradation with a line head. A digital printer of printing a picture by recording a plurality of lines on a recording paper with scanning by the line head, comprising counting devices (5-1, 5-2) for counting a number of pixels to print at each gradation, dividing devices (9-1, 9-2, 12-1, 12-2, 13-1, 13-2) for dividing all pixels into several groups in accordance with the counting devices and deciding devices (10-1, 10-2, 11-1, 11-2) for deciding a number of groups. A range of grouping and as number of groups can be changed so as for a number of printing pixels in every group to be equal to a predetermined number of simultaneous turn-on pixels.

Abstract: A gradational printing method for performing a gradational printing by energizing a plurality of heat emitting elements arranged on a thermal head correspondingly to respective bits of digital gradation data representing a gray level. In case of this method, the plurality of heat emitting elements are divided into two or more blocks and the blocks are energized correspondingly to different bits of the digital gradation data. Thus, an energizing time, during which a maximum current should be supplied, can be reduced. Further, the weight of the printer can be light. Moreover, if the maximum electric current of a printer is equal to that of the conventional method, the duration thereof can be equal to the minimum duration of the energizing pulses corresponding to the bits of the gradation data. Consequently, the capacities of a power supply and a printer employing this method can be small. Further, the size and manufacturing cost of the power supply and the printer can be small.

Abstract: A thermal printing apparatus for printing input gradational images, characters and figures by using multilevel density which can appropriately regulate the levels of the densities representing the gradational images etc.

Abstract: A heat-sensitive hot-melt image transfer sheet transfers an ink image to a recording sheet when selectively heated by the heating element of the thermal head of a thermal printer. The image transfer sheet comprises a base coated on a surface thereof with a matrix of circular hot-melt ink dots at a constant pitch. The hot-melt ink dots are selectively meltable with heat applied through the base by the heating elements for transferring an ink image to the recording sheet held against the matrix of hot-melt ink dots.

Abstract: A method for manufacturing a color separation plate for screen dot color printing, having screen dots recorded thereon, the size of the screen dots corresponding to the density of one of the primary colors of an image to be printed, by one of the color signals corresponding to respective primary colors and obtained by reading out the image to generate an electric signal corresponding to the image and separating the electric signal into the color signals corresponding to the primary colors, respectively. A sheet of recording material (12) which is transparent and applicable to thermal transfer recording is prepared. Also prepared is a rotatable flat platen (11). The sheet (12) of the recording material is put on the flat platen and the flap platen is rotated by a specific angle from the position where the sheet of the recording material is put on the flat platen.

Abstract: A thermal printing apparatus prints input gradational images, characters and figures by using multilevel density regulates the levels of the densities representing the gradiational images etc. to be printed by a linear thermal head having n heating resistors arranged in a row.

Abstract: A thermal printer comprises a thermal head and a printing data output circuit outputting printing data. A portion of the printing data is copied. The copied portion of the printing data is added to a head of the printing data to form a combination of the copied portion and the printing data. The data combination is outputted to the thermal head. The thermal head is driven with the copied portion to preheat the thermal head. Then, the thermal head is driven with the printing data to perform actual printing.

Abstract: A gradation control device for a thermal ink-transfer type printing apparatus controls an applying time of a current to each of heating elements of a thermal printing head depending on a voltage drop introduced between a power source and the thermal printing head, so that it is possible to constantly print the same gradation level with the same printing dot size regardless of the printing data.

Abstract: A color correcting circuit for thermal printer comprises a first circuit for obtaining a first degree correction operation result, a second circuit for obtaining a second degree correction operation result, and a difference limiting circuit for selectively outputting a correction data. The first degree correction operation makes the relationship between the density of an input image and the density of an output image linear for each primary color. The second degree correction operation reduces a difference between the density of the input image and the density of the output image by use of the method of least squares for each primary color.

Abstract: A structure of a thermal head of the type using an ink paper or a heat-sensitive paper is disclosed. The structure includes an array of units each comprising a single resistance body and a pair of electrode members which respectively correspond to a first and a second heat-generating portions positioned at both ends of the resistance body, the electrode members being adapted to energize the resistance body. At least one of the first and second heat-generating portions of the resistance body is divided into a plurality of heat-generating members, and so is done one of the electrode members which is associated with those heat-generating members.

Abstract: A picture information processing system processes a picture information so that a printing area of each of dots constituting a picture is variably set depending on printing areas of the dots surrounding each dot. The picture information processing system comprises a memory for pre-storing an optimum printing area of a dot for each of dot patterns. The optimum printing area of one dot is obtained depending on the printing areas of the dots surrounding the one dot, and the optimum printing area is obtained for each of the dot patterns which are formed by the one and the surrounding dots.