Abstract: A projection display unit includes: a light modulation panel which modulates light from a light source in accordance with a given image signal; an iris diaphragm which regulates, by changing a diaphragm diameter, a transmission amount of light modulated by the light modulation panel; a histogram creator which creates a histogram of a luminance signal distribution of the image signal; a histogram analyzer which analyzes the created histogram to specify high-luminance and low-luminance reference values in the histogram; a reference value derivation section which derives a single reference value from both the high-luminance reference value and the low-luminance reference value specified by the histogram analyzer; and an iris controller which determines the diaphragm diameter of the iris diaphragm for the light modulated by the light modulation panel in accordance with the image signal on the basis of the single reference value specified by the reference value derivation section.

Abstract: A projection display unit includes: a light modulation panel which modulates light from a light source in accordance with a given image signal; an iris diaphragm which regulates, by changing a diaphragm diameter, a transmission amount of light modulated by the light modulation panel; a histogram creator which creates a histogram of a luminance signal distribution of the image signal; a histogram analyzer which analyzes the created histogram to specify high-luminance and low-luminance reference values in the histogram; a reference value derivation section which derives a single reference value from both the high-luminance reference value and the low-luminance reference value specified by the histogram analyzer; and an iris controller which determines the diaphragm diameter of the iris diaphragm for the light modulated by the light modulation panel in accordance with the image signal on the basis of the single reference value specified by the reference value derivation section.

Abstract: In the data-transmitting apparatus, the image-comparing circuit compares, when a request for updating the image displayed is made, the image data item being input, with the image data item stored in the memories, which represents the preceding frame. The circuit therefore calculates the difference between the image data items compared. If the difference thus calculated by the image-comparing circuit is smaller than a prescribed value (if No in Step S1), the transmission-region data processing circuit generates, from the difference of the image data, the data that represents that part of the image data which corresponds to a region to be transmitted, and the data that represents this region. These data items generated by the circuit are transmitted. If the difference thus calculated is equal to or greater than the prescribed value (if Yes in Step S1), the coarse-image data processing circuit generates coarse image data, which is transmitted.

Abstract: In the data-transmitting apparatus, the image-comparing circuit compares, when a request for updating the image displayed is made, the image data item being input, with the image data item stored in the memories, which represents the preceding frame. The circuit therefore calculates the difference between the image data items compared. If the difference thus calculated by the image-comparing circuit is smaller than a prescribed value (if No in Step S1), the transmission-region data processing circuit generates, from the difference of the image data, the data that represents that part of the image data which corresponds to a region to be transmitted, and the data that represents this region. These data items generated by the circuit are transmitted. If the difference thus calculated is equal to or greater than the prescribed value (if Yes in Step S1), the coarse-image data processing circuit generates coarse image data, which is transmitted.