Intensity correction device

Assignee: Panasonic Holdings Corp

•

Filing: 1992-06-25

•

Granted: —

•

Expires: 2012-06-25

📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract The invention relates to an intensity correction device for automatically adjusting an intensity of an input video signal to an optical image by detecting characteristics of the input image, and intends to provide intensity correction with maintaining clear image by reducing magnitude of correction or by not effecting correction when the luminance level of the input luminance signal is concentrated to a certain luminance level. The intensity correction device includes a histogram memory (1), a look-up table operating circuit (2), a look-up table (3), a maximum value detecting circuit (4), and an invertor (5) and a multiplier (6), limiter (7), or a gain control circuit. By this, when the luminance level of the input video signal is concentrated to the certain luminance level, magnitude of correction can be reduced or made zero. Therefore, by detecting the characteristics of the input image, the intensity of the input video signal can be automatically corrected to the optimal image for providing better picture quality.

Inventors

👤 Yosuke Izawa
👤 Naoji Okumura

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 11:47

CPC Classifications

G; G06; G06T; G06T5/00; G06T5/90; G06T5/92; G06T5/40; H; H04; H04N; H04N5/00; H04N5/14; H04N5/20

Claims Analysis

Total Claims: 4

Claim 1

Independent Claim 90 words

An intensity correction device comprising: a histogram memory (1) for forming histogram of an input luminance signal; a look-up table operating circuit (2) for cumulating the histogram and normalizing so that the maximum cumulative frequency becomes the maximum value of an output luminance signal; a look-up table memory (3) for storing the normalized data and outputting a correction signal; a maximum value detecting circuit (4) for detecting the maximum value of the histogram; and a multiplier (6) for multiplying an inverse value of the maximum value and the correction signal.

Claim 2

Dependent Claim 93 words

An intensity correction device comprising: a histogram memory (1) for forming histogram of an input luminance signal; a look-up table operating circuit (2) for cumulating the histogram and normalizing so that the maximum cumulative frequency becomes the maximum value of an output luminance signal; a look-up table memory (3) for storing the normalized data and outputting a correction signal; a maximum value detecting circuit (4) for detecting a maximum value of differences of the normalized data; and a multiplier (6) for multiplying an inverse value of the maximum value and the correction signal.

Claim 3

Dependent Claim 95 words

An intensity correction device comprising: a histogram memory (1) for forming histogram of an input luminance signal; a look-up table operating circuit (2) for cumulating the histogram and normalizing so that the maximum cumulative frequency becomes the maximum value of an output luminance signal; a look-up table memory (3) for storing the normalized data and outputting a correction signal; a maximum value detecting circuit (4) for detecting a maximum value of differences of the normalized data; and a limiter (7) for setting the correction signal to zero when said maximum value exceeds a predetermined value.

Claim 4

Dependent Claim 94 words

An intensity correction device comprising: a histogram memory (1) for forming histogram of an input luminance signal; a look-up table operating circuit (2) for cumulating the histogram and normalizing so that the maximum cumulative frequency becomes the maximum value of an output luminance signal; a look-up table memory (3) for storing the normalized data and outputting a correction signal; a maximum value detecting circuit (4) for detecting a maximum value of differences of the normalized data; and a gain control circuit (8) for varying gain of said correction signal depending upon said maximum value.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag

Select Category

Notes (Optional)