Abstract: An automatic tone correction apparatus comprises a luminance distribution formation circuit for forming a luminance histogram of an input image; a center-of-gravity calculation circuit for calculating the center of gravity of a low-luminance part of the luminance histogram; a distribution range calculation circuit for calculating a maximum value and a minimum value on an input luminance level axis; a target value storage circuit for holding a luminance correction target value; a correction table formation circuit for forming a correction table for expanding the luminance distribution and, simultaneously, correcting the luminance histogram so that the center of gravity matches the luminance correction target value; and an image signal correction circuit for performing tone correction on the basis of the correction table. Therefore, whether the input image is a forward-light image or a back-lighted image, the apparatus performs tone correction using the same processing.

Abstract: In an image input apparatus having an image sensor that is composed of plural chips, the stepwise difference in density on a chip boundary is made inconspicuous by a limited amount of compensation memory. The image input apparatus obtains the stepwise differences in density between pixels that are positioned in adjacent places to adjoining chips of the image sensor and for plural lines, averages the differences, reads an image, and displays the same on a screen after compensating for the stepwise difference in density between the chips for each line by using the average value.

Abstract: A communication apparatus is provided for allowing any image contained in data exchanged between communication terminals such as mobile phones to be properly displayed in accordance with the capabilities of the receiving communication terminals. The communication apparatus can properly display an image according to the capabilities of a receiving communication terminal because the properties of the image are converted to suit the capabilities of the receiving communication terminal. When a plurality of images are combined or a modification is made to an image in communication terminals such as mobile phones and the resulting image or images are transmitted, the image properties of each image are converted to suit the capabilities of each receiving communication terminal before the combination or modification. Thus, any image can be properly displayed in accordance with the capabilities of the receiving communication terminal.

Abstract: An automatic tone correction apparatus comprises a luminance distribution formation circuit for forming a luminance histogram of an input image; a center-of-gravity calculation circuit for calculating the center of gravity of a low-luminance part of the luminance histogram; a distribution range calculation circuit for calculating a maximum value and a minimum value on an input luminance level axis; a target value storage circuit for holding a luminance correction target value; a correction table formation circuit for forming a correction table for expanding the luminance distribution and, simultaneously, correcting the luminance histogram so that the center of gravity matches the luminance correction target value; and an image signal correction circuit for performing tone correction on the basis of the correction table. Therefore, whether the input image is a forward-light image or a back-lighted image, the apparatus performs tone correction using the same processing.

Abstract: In an image input apparatus having an image sensor composed of plural chips, the stepwise difference in density on a chip boundary is made inconspicuous by a few compensation memories.

Abstract: A thermosensitive recording sheet comprising a support and a thermosensitive color developer layer thereon containing a basic leuco dye and an organic color developer, said layer containing a bis-phenyl sulfone compound selected from bis-(3-phenyl-4-hydroxyphenyl)sulfone and bis-(2-methyl-4-hydroxy-5-cyclohexylphenyl)sulfone as the organic color developer.

Abstract: A heat sensitive recording material having a support and a color-developing layer which comprises both as a colorless basic chromogenic dye at least one of a particular fluorane-type leuco dye and a particular divinyl compound, the heat-sensitive recording material of this invention having superior thermal responsibility, light resistance, weather resistance, oil resistance and optical readability in the near infrared region.

Abstract: A thermosensitive recording sheet having a thermosensitive color developer layer containing a basic leuco dye and an organic color developer, said layer containing a compound of the formula ##STR1## as a sensitizer.

Abstract: A heat-sensitive recording material including a support and a color-developing layer comprising an electron doner, an electron acceptor and a fluorescence-dyestuff and/or pigment. The heat-sensitive recording material is superior in both readability in an irradiation of UV-ray and optical readability in near infrared region.

Abstract: A heat-sensitive recording material has a support and a color-developing layer which comprises a particular sulfone as an organic color-developing agent and a particular fluorene-type leuco dyestuff as a colorless basic chromogenic dyestuff. This heat-sensitive recording material is superior in light resistance, weather resistance, oil resistance and optical readability in the near infrared region.

Abstract: A heat-sensitive recording material comprises a support and a color-developing layer having a particular saturated higher fatty acid iron salt, a particular polyvalent phenolic derivative and a colorless leuco dyestuff.The heat-sensitive recording material of the present invention provides both a superior image contrast and a high stability of developed image against oily substances and solvents.

Abstract: A heat-sensitive recording material has a substrate and a color-developing layer which comprises a near infrared-absorbing fluorantype leuco dye.This heat-sensitive recording material provides a superior optical readability in near infrared region.

Abstract: A heat- and light-sensitive recording material has a substrate and a color-forming layer which comprises a particular fluoran-type leuco dye.This heat- and light-sensitive recording material provides a clear image a superior contamination-resistance and an excellent readability in visible and near infrared range.

Abstract: A heat-sensitive recording material has a support and a color-developing layer which comprises both as a colorless basic chromogenic dye at least one of a particular fluorane-type leuco dye and a particular divinyl compound and as a stabilizer a particular halogen-substituted zinc benzoate derivative.This heat-sensitive recording material is superior in light resistance, weather resistance, oil resistance and optical readability in the near infrared region.

Abstract: A heat-sensitive recording material including a support and a color-developing layer having both an electron donor and a metal double salt or higher fatty acid having 16-35 carbon atoms as an electron acceptor. The heat-sensitive recording material is superior is dispersibility, image contrast, oil resistance, solvent resistance and optical readability in the near infrared region.

Abstract: A heat-sensitive recording material comprises a support and a color-developing layer having both a particular saturated higher fatty acid iron salt and a particular polyvalent phenolic derivative. The heat-sensitive recording material provides a superior thermal response and a high stabilty of the developed image.

Abstract: A thermosensitive recording sheet having a thermosensitive color developing layer containing a basic leuco dye and an organic color developer, said organic color developer consisting of at least partly of a halogen-substituted benzoic acid zinc salt represented by the following general formula ##STR1## wherein X.sub.1 represents a halogen atom, X.sub.2 represents a hydrogen or halogen atom, and R.sub.1, R.sub.2 and R.sub.3, independently from each other, represent a hydrogen atom or an alkyl, alkoxy, cycloalkyl, nitro, cyano or hydroxyl group.

Abstract: Heat-sensitive recording sheet comprising in a heat-sensitive color forming layer a colorless basic dyestuff and 4-isopropoxy-4'-hydroxydiphenyl sulfone as organic developer, wherein said color forming layer contains as sensitizer one of the compounds represented by the following formula (II) or (III): ##STR1## where, in the general formula (II) and (III), A represents a hydrogen atom, halogen atom, nitro group, lower alkyl group, lower alkoxy group or hydroxy group, l represents an integer from 1 to 5 and m represents an integer from 0 to 3. The sheet provides high density images and excellent stability of images.

Abstract: A heat-sensitive recording sheet comprising both calcium monobenzyl phthalate as stabilizer and 4-isopropoxy-4'-hydroxy diphenylsulfone and/or 4-methyl-4'-hydroxy diphenylsulfone as organic developer in heat-sensitive layer which comprises a basic colorless dyestuff and an organic developer. This heat-sensitive recording sheet provides the improved stability of developed color image against sticking of hair tonics and oils, etc.

Abstract: A thermosensitive recording sheet having a thermosensitive color developing layer containing a basic leuco dye and an organic color developer, said layer containing a polyphenyl ester compound of the general formula ##STR1## wherein R.sup.1 and R.sup.2, independently from each other, represent an alkyl group, a cycloalkyl group, or an aryl, aralkyl or aryloxyalkyl group which may have at least one substituent selected from the class consisting of halogen atoms, nitro groups, hydroxyl groups, lower alkyl groups and lower alkoxy groups.