To obtain a good image, let's look at 4 important factors in camera + lens + lighting from bad examples.
Relation between the color of light and the color of objects
R
The image obtained depends on what color of lighting is applied to the color of the target subject.
The Three Primary Colors of Light
The three most basic colors are Red, Green, and Blue and are represented by the acronym RGB. Mixing the three colors of light in equal proportions produces white light. Indoor lighting such as fluorescent lamps and sunlight appear white because the various colors of light are mixed in proportion to each other. In addition, almost any color can be produced by controlling the balance of RGB.
B
G
Color visibility of objects
The Three Primary Colors of Light
The color of an object is determined by the color of the light that reaches the object from a light source, such as the sun, and is reflected without being absorbed by the object. (Example 1) If white light is shined on a red apple, it will appear red because it absorbs blue and green light and reflects only red. If green light is shined on a red apple, it absorbs green and reflects no color, making it appear black. (Example 2) When white light is shined on a yellow banana, it absorbs blue light and reflects a mixture of red and green light, making it appear yellowish. "If you shine blue light on a yellow banana, it absorbs blue and appears blackish because it absorbs blue.
❶ Resolution
❷ Focus
❸ Contrast
The lighting is uneven on both sides and top and bottom, and the lighting is partly reflected in the image making it too bright. ❹ Brightness uniformity Lighting should be adequate for the object and from the appropriate position. To make it a good image
Without the correct focus, the overall image will be blurred.
Lack of contrast between black and white results in an unclear image.
Poor resolution leads to "not being able to see what you want to see."
The clarity of an object is determined by the color of its light.
Using this property, we can control whether an object is "brightened" or "darkened" by using monochromatic lighting on a colored object. "In fact, using a monochrome camera and lighting a red (R) green (G) and blue (B) object with each color of red (R), green (G), and blue (B) will produce the following image.
To make it a good image To make it a good image To make it a good image
Adjust the brightness of the lighting and the shutter speed of the camera to clearly define the areas you want to emphasize and those you prefer not to.
The basic idea is to focus on the object by adjusting the depth of field with the aperture and brightness of the lighting. (In some cases, the image may be intentionally blurred.)
Select a camera/lens with a resolution appropriate for the accuracy you wish to detect.
Under red lighting
original image
Under green lighting
Under blue lighting
❶ Resolution ❷ Focus ❸ Contrast ❹ Brightness uniformity
By being aware of all the four aspects
As shown above, when the light source color that includes the color of the object is irradiated, the object can be imaged brightly (white). Conversely, if the object is illuminated by a light source color that does not include the object's color, the object can be imaged dark (black). The same property can be used to ""darken/lighten"" defects (scratches and stains) on an object. (Example 3) When detecting blue stains on a red object, red lighting can be used to capture the object brighter and the stain darker, resulting in a high-contrast image.
comprehensively, you can produce a quality image such as the one on the left.
In addition to highlighting defects, the same concept of lighting selection can be used to eliminate excess background or unnecessary objects. *Color cameras often use white lighting to take advantage of this feature.
In the following pages, we will explain how "lighting" changes the visual appearance of an object.
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