JPH0197669U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of an image reading device according to the present invention, and FIG. 2a is a side view for explaining a black reference board used in the embodiment.
FIG. 2b is a plan view of the black reference substrate shown in FIG. 2a,
3 is a circuit diagram showing details of the comparator shown in FIG. 1, FIGS. 4 a to 4 f are timing charts showing operation examples of the same embodiment, and FIG. 5 is a diagram of another image reading device according to the present invention. 6a and 6b are schematic diagrams for explaining the embodiment shown in FIG. 5, FIG. 7 is a block diagram showing an example of a conventional image processing circuit, and FIG. The figure is a front view showing an example of a general optical system, and FIG. 9 is a block diagram showing another example of a conventional image processing circuit. 30... Correction section (differential amplifier circuit), 33... Comparator, 34... Correction value calculation section (counter), 40... Image sensor (CCD).

Claims (1)

[Scope of utility model registration request] An image reading device that performs an image capturing operation using an image sensor includes a comparator that compares a preset black level with a black level signal output from the image sensor, and correction based on the comparison result of this comparator. a correction value calculation unit that calculates the value;
An image reading device comprising: a correction section that corrects a value of a pixel signal output from the image sensor based on the correction value output from the correction value calculation section.