Video camera

A video camera comprising:

• A/D conversion means for converting analog video signals obtained from a camera device to digital video signals;
• clamp means for clamping a black level of the digital video signals at a black level correction value;
• sampling means for sampling a brightness of the digital video signals to obtain brightness samples;
• comparison means for comparing the brightness samples with a reference value at predetermined intervals;
• a counter for counting a number of times S that the brightness samples are lower, during the predetermined intervals, than the reference value;
• determination means for determining whether the number of times S is more or less than a predetermined number of times B;
• reference value updating means for decreasing the reference value of said comparison means by a predetermined value to be a next updated reference value when S is determined to be not less than B, S.gtoreq.B;
• and
• black level correction value setting means for setting said black level correction value according to the reference value when S is determined to be less than B, S<B, and providing said clamp means with said black level correction value.

A device for processing video signals comprising:

• black level correction means for correcting a black level of video signals;
• determination means for determining whether a backlight correction condition exists;
• and
• stopping means for discontinuing correction of said black level for said video signals by said black level correction means when said backlight correction condition is determined to exist by said determination means.

A device for processing video signals comprising:

• black level correction means for correcting a black level of video signals;
• determination means for determining whether a control value of automatic gain control means is a predetermined value or more;
• and
• stopping means for discontinuing correction of said black level for said video signals by said black level correction means when said control value is determined to be said predetermined value or more by said determination means.

A method for processing video signals comprising the steps of:

• (a) correcting a black level of the video signals;
• (b) determining whether a backlight correction condition exists;
• and
• (c) discontinuing correction of said black level for said video signals by said step (a) when said backlight correction condition is determined to exist at said step (b).

A method for processing video signals comprising the steps of:

• (a) correcting a black level of the video signals;
• (b) determining whether a control value of automatic gain control means is a predetermined value or more;
• and
• (c) discontinuing correction of said black level for the video signals by said step (a) when said control value is determined to be said predetermined value or more at said step (b).

A method for processing video signals comprising the steps of:

• (a) receiving analog video signals;
• (b) converting said analog video signals received at said step (a) to digital video signals;
• (c) clamping a black level of said digital video signals at a black level correction value;
• (d) sampling a brightness of said digital video signals to obtain brightness samples;
• (e) comparing said brightness samples sampled at said step (d) with a reference value at predetermined intervals;
• (f1) counting a number of times S that the brightness samples are lower, during the predetermined intervals, than the reference value;
• (f2) determining whether the number of times S is more or less than predetermined number of times B;
• (g) increasing said reference value by a predetermined value to be an updated reference value when S is determined to be less than B, S<B, at said step (f2);
• and
• (h) setting said black level correction value according to said reference value S is determined to be not less than B, S.gtoreq.B, and providing said step (c) with said black level correction value.

A method for processing video signals comprising the steps of:

• (a) receiving analog video signals;
• (b) converting said analog video signals received at said step (a) to digital video signals;
• (c) clamping a black level of said digital video signals at a black level correction value;
• (d) sampling a brightness of said digital video signals to obtain brightness samples:
• (e) comparing said brightness samples sampled at said step (d) with a reference value at predetermined intervals;
• (f1) counting a number of times S that the brightness samples are lower, during the predetermined intervals, than the reference value;
• (f2) determining whether the number of times S is more or less than a predetermined number of times B;
• (g) decreasing said reference value by a predetermined value when S is determined to be not less than B, S.gtoreq.B, at said step (f2);
• and
• (h) setting said black level correction value according to said reference value when S is determined to be less than B, S<B, and providing said step (c) with said black level correction value.

A device for processing video signals comprising:

• black level correction means for correcting a black level of video signals;
• first determination means for determining whether a backlight correction condition exists;
• first stopping means for discontinuing correction of said black level for said video signals by said black level correction means when said backlight correction condition is determined to exist by said determination means;
• second determination means for determining whether a control value of automatic gain control means is a predetermined value or more;
• and
• second stopping means for discontinuing correction of said black level for said video signals by said black level correction means when said control value is determined to be said predetermined value or more by said determination means.

A method for processing video signals comprising the steps of:

• (a) correcting a black level of the video signals;
• (b) determining whether a backlight correction condition exists;
• (c) discontinuing correction of said black level for said video signals by said step (a) when said backlight correction condition is determined to exist at said step (b);
• (d) determining whether a control value of automatic gain control means is a predetermined value or more;
• and
• (e) discontinuing correction of said black level for the video signals by said step (a) when said control value is determined to be said predetermined value or more at said step (d).