An image pickup apparatus for automatically controlling image signal output level and an image pickup method

Claim 2

An image pickup apparatus for controlling an image signal output level automatically, comprising: image pickup means (9); amplifier means (11) for amplify­ing an output of the image pickup means (9) to have a desired level; and output level detector means (18) for detecting an output level of the amplifier means (11), whereby an amplification degree of the amplifier means (11) is controlled by an output of the output level detector means (18) and an image signal output is provided by an output of the amplifier means (11).

Claim 3

An image pickup apparatus according to Claim 1, wherein the image pickup means (9) is of the type of variable charge storage time, and said image pickup apparatus further comprises: storage means (13) for storing an output of the amplifier means (11); selector means (15) for selecting one of an output of the amplifier means (11) and an output of the storage means (13); comparator means (19) for comparing an output of the output level detector means (18) with at least one preset reference level; and control means (20) for controlling the length of the charge storage time of the image pickup means (9), the writing and reading operations in and from the storage means (13), respec­tively, and the selection by the selector means (15).

Claim 4

An image pickup apparatus according to Claim 2, wherein the length of the charge storage time of the image pickup means (9) is controlled to be increased by the control means (20) when the illuminance of an object decreases.

Claim 5

An image pickup apparatus according to Claim 2, wherein the length of the charge storage time of the image pickup means (9) is controlled to be decreased by the control means (20) when the illuminance of an object increases.

Claim 6

An image pickup apparatus according to Claim 2, further comprising a read pulse generator (10) for outputting a read pulse for controlling an operation of reading an image signal from the image pickup means (9), whereby the length of the charge storage time of the image pickup means (9) is controlled by changing the width of the read pulse outputted from the read pulse generator (10) by an output signal of the control means (20).

Claim 7

An image pickup apparatus according to Claim 2, wherein the storage means is composed of an A/D converter (12), an image memory (13) and a D/A converter (14).

Claim 8

An image pickup apparatus according to Claim 6, wherein the operations of writing and reading an intermittent signal in and from the image memory (13), respectively, are driven by image memory drive means (17) interposed between the image memory (13) and the control means (20).

Claim 9

An image pickup apparatus according to Claim 1, wherein the output level detector means (18) is composed of an integrator circuit.

Claim 10

An image pickup apparatus according to Claim 2, wherein the comparator means (19) is provided with a plurality of reference voltages.

Claim 11

An image pickup apparatus according to Claim 2, wherein the selectable positions of the selector means (15) include a normal position connected to the output of the amplifier means (11) and an sensitivity improvement position connected to the output of the storage means (13), a closed loop being formed to include the amplifier means (11) and the output level detector means (18) when the normal position is selected, while, a closed loop being formed to include the amplifier means (11), the storage means (13) and the output level detector means (18) when the sensitivity improvement position is selected.

Claim 12

An image pickup method using an image pickup apparatus for controlling an image signal output level automatically, wherein said image pickup apparatus comprises image pickup means (9), amplifier means (11) for amplifying an output of the image pickup means (9) to have a desired level, output level detector means (18) for detecting an output level of the amplifier means (11) and controlling an amplification degree of the amplifier means (11), storage means (13) for storing an output of the amplifier means (11), selector means (15) for selecting one of an output of the amplifier means (11) and an output of the storage means (13), compar­ator means (19) for comparing an output of the output level detector means (18) with at least one preset reference level, and control means (20) for controlling the length of the charge storage time of the image pickup means (9), the writing and reading operations in and from the storage means (13), respectively, and the selection by the selector means (15), said image pickup method comprising the steps of: (a) producing an image signal output of a constant level when an object has normal illuminance, in which an image signal outputted from the image pickup means (9) is amplified through the amplifier means (11), transmitted through the selector means (15) which has been set to select the output of the amplifier means (11), and is fed back to the amplifier means (11) via the output level detector means (18); and (b) maintaining an image signal output at a constant level even when the illuminance of an object changes, in which the change of the illuminance of the object is detected by the output level detector means (18) and the comparator means (19), the resulting information of detection is transmitted to the control means (20) which operates to control the setting of the charge storage time of the image pickup means (9) so as to compensate for the change of the illuminance of the object, the drive of the writing and reading operations in and from the storage means (13), respec­tively, and the selection by the selector means (15), and then the output level detector means (18) operates to control the amplification degree of the amplifier means (11).

Claim 13

An image pickup method using an image pickup apparatus for controlling an image signal output level automatically, wherein said image pickup apparatus comprises image pickup means (9), amplifier means (11) for amplifying an output of the image pickup means (9) to have a desired level, output level detector means (18) for detecting an output level of the amplifier means (11) and controlling an amplification degree of the amplifier means (11), storage means (13) for storing an output of the amplifier means (11), selector means (15) for selecting one of an output of the amplifier means (11) and an output of the storage means (13), compar­ator means (19) for comparing an output of the output level detector means (18) with at least one preset reference level, and control means (20) for controlling the length of the charge storage time of the image pickup means (9), the writing and reading operations in and from the storage means (13), respectively, and the selection by the selector means (15), said image pickup method comprising the steps of: (a) producing an image signal output of a constant level when an object has normal illuminance, in which an image signal outputted from the image pickup means (9) is amplified through the amplifier means (11), transmitted through the selector means (15) which has been set to select the output of the amplifier means (11), and is fed back to the amplifier means (11) via the output level detector means (18); and (b) maintaining an image signal output at a constant level even when the illuminance of an object changes, in which the change of the illuminance of the object is detected by the output level detector means (18) and the comparator means (19), the resulting information of detection is transmitted to the control means (20) which operates to control the setting of the charge storage time of the image pickup means (9) so as to compensate for the change of the illuminance of the object, the drive of the writing and reading operations in and from the storage means (13), respec­tively, and the selection by the selector means (15), and then the output level detector means (18) operates to control the amplification degree of the amplifier means (11).

Claim 14

An image pickup method according to Claim 11, wherein the control means (20) controls to decrease the length of the charge storage time of the image pickup means (9) when the magnitude of the illuminance of the object increases.

Claim 15

An image pickup method according to Claim 11, wherein the control means (20) controls to increase the length of the charge storage time of the image pickup means (9) when the magnitude of the illuminance of the object decreases.