Image processing device, image processing method, and image processing program

Patent metadata

Field	Value
Publication number	US-11238570-B2
Application number	US-201816960676-A
Country	US
Kind code	B2
Filing date	Jan 29, 2018
Priority date	Jan 29, 2018
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

An image processing device, an image processing method, and an image processing program capable of appropriately correcting contrast even for an image in which the amplitude of the reflection rate differs for each local area of the image. An image processing device, including a signal intensity extraction unit configured to extract signal intensity of an input image; a peripheral region reference value calculator configured to calculate a peripheral region reference value based on the signal intensity of a peripheral region located around a small region of interest; and an emphasis degree determination unit configured to determine an emphasis degree of the signal intensity so as to increase the signal intensity of the small region, wherein the signal intensity is defined as a reflection rate in the input image input to the image processing device, the small region is defined as a region which is a part of the input image.

First claim

The invention claimed is:

1. An image processing device, comprising:
a signal intensity extraction unit executing an operation on an input image input to the image processing device and calculating a reflection rate of the input image as signal intensity;
a peripheral region reference value calculator calculating, for each small region, a peripheral region reference value based on the signal intensity of a peripheral region located around the small region of interest;
an emphasis degree determination unit determining an emphasis degree of the signal intensity to correct and increase the signal intensity of the small region; and
a conversion output unit obtaining a corrected value of the signal intensity of the small region using the emphasis degree,
wherein
the small region is defined as a region which is a part of the input image and further comprises at least one pixel, and
the emphasis degree is monotonically non-decreasing with respect to a difference between the peripheral region reference value and a predetermined value, and
further satisfying conditions of:
S≤T≤OL , when R≥ 0, and
UL≤T≤S , when R< 0,

wherein R represents the signal intensity of the small region of interest,
S represents the peripheral region reference value,
T represents the predetermined value, and
OL and UL respectively represent an upper limit and a lower limit of the signal intensity that can be output as an output image.

2. The image processing device of claim 1 , wherein the signal intensity is calculated on the basis of a reflected light component and an illumination light component separated from the input image input to the image processing device.

3. An image processing method, comprising:
extracting signal intensity of executing an operation on an input image input to the method and calculating a reflection rate of the input image as signal intensity;
calculating, for each small region, a peripheral region reference value based on the signal intensity of a peripheral region located around the small region of interest;
determining an emphasis degree of the signal intensity to correct and increase the signal intensity of the small region; and
obtaining a corrected value of the signal intensity of the small region using the emphasis degree,
wherein
the small region is defined as a region which is a part of the input image and comprises at least one pixel, and
the emphasis degree is monotonically non-decreasing with respect to a difference between the peripheral region reference value and a predetermined value, and
further satisfying conditions of:
S≤T≤OL , when R≥ 0, and
UL≤T≤S , when R≤ 0,

wherein R represents the signal intensity of the small region of interest,
S represents the peripheral region reference value,
T represents the predetermined value, and
OL and UL respectively represent an upper limit and a lower limit of the signal intensity that can be output as an output image.

4. A non-transitory computer-readable storage medium storing an image processing program for causing a computer to perform a predetermined function, the predetermined function comprising the functions of:
executing an operation on an input image input to the method and calculating a reflection rate of the input image as signal intensity;
calculating, for each small region, a peripheral region reference value based on the signal intensity of a peripheral region located around the small region of interest;
determining an emphasis degree of the signal intensity to correct and increase the signal intensity of the small region; and
obtaining a corrected value of the signal intensity of the small region using the emphasis degree,
wherein
the small region is defined as a region which is a part of the input image and comprises at least one pixel, and
the emphasis degree is monotonically non-decreasing with respect to a difference between the peripheral region reference value and a predetermined value, and
further satisfying conditions of:
S≤T≤OL , when R≥ 0, and
UL≤T≤S , when R< 0,

wherein R represents the signal intensity of the small region of interest,
S represents the peripheral region reference value,
T represents the predetermined value, and
OL and UL respectively represent an upper limit and a lower limit of the signal intensity that can be output as an output image.

Assignees

• Eizo Corp

Inventors

• Goto Kyohei
• Nakamae Takashi
• Aoki Reo

Classifications

• H04N1/407

  Control or modification of tonal gradation or of extreme levels, e.g. background level · CPC title

• G06T7/136

  involving thresholding · CPC title

• G06T5/50

  using two or more images, e.g. averaging or subtraction · CPC title

• H04N1/6027

  Correction or control of colour gradation or colour contrast (H04N1/6058 takes precedence) · CPC title

• G06T5/008 Primary

  Physics · mapped topic