Setting Measurement Conditions
3-14
3
(10) Gray level change
To change the gray level, you can change the "**.*TIMES" (magnification by N processing), the "
γ
+,"
"
γ
-" (
γ
(positive/negative) correction), the "CHNG-L" (widening histogram), and the "INCRS-M" (mid
emphasis) functions.
Æ
Setting screen
[TYPE MEAS COND]
1
OBJECT TYPE NO.
00(0~63) NO YES
[MEAS 1 CAM1 COND]
3
CHNG GRAY LVL
NO YES(00.0TIMES
γ
+
γ
- CHNG-L INCRS-M
)
4
SPACE FILTER
NO
NUM-OF-TIMES1(
0
〜
5
)
OPS-MENU RETURN LOCK
When "OBJECT TYPE
NO." is set to 00.
When "MEASUREMENT
1" is selected.
Details
Gray level change
Magnification by N
processing
(**.* TIMES)
γ
(positive/negative)
correction
Histogram
widening
Mid emphasis
To improve the contrast (the ratio of high value gray levels to low value gray
levels), specify a magnification rate (00.0 to 99.9) for multiplying the image
data.
- If the magnified gray level exceeds 255, the system will correct the value
to 255.
-
γ
positive correction: used when the mid gray level is too low.
255
255
Input image gray level
Output image gray level
255
255
Input image gray level
Output image gray level
-
γ
negative correction: used when the mid gray level is too high.
This is a method to widen the histogram of an image in which the histogram
is at part of it, thus improve its contrast.
Emphasize the mid gray level.
- This improves contrast while remaining the background image.
- The input image density (G) can be converted to the output image density
with the following formulas:
0
Z
m
a
b
0
Z
m
2
Good contrast image
Gray level
Gray level
1
Bad contrast image
0
to
127
128
to
255
（Ｇ÷127）
2
×127
（（Ｇ−128）÷127×127）＋127
Output image gray level
Input image gray level(G)
