Welding condition monitoring device
First Claim
1. A welding condition monitoring device for monitoring a welding state of a welding work portion by taking an image thereof by an image sensor, which device has a means for selectively emphasizing outputs of the image sensor for any of luminance areas of the image by using an output-characteristic conversion table for the image sensor, whereby outputs relating to a high luminance welding portion and outputs relating to a low luminance bead portion area are emphasized respectively to increase a contrast between the currently welding portion and the already formed bead portion in the image, and outputs relating to an area between the high luminance welding portion and the low luminance bead portion area is fixed to a constant level, and signals of other remaining areas are omitted by compression,and wherein each of plural light sensor circuits composing the image sensor represents a unit pixel and has a logarithmic output characteristic, and each of the light sensor circuits composing the image sensor represents a unit pixel and comprises a MOS transistor capable of converting a current flowing in a photodiode into a voltage signal with a logarithmic output characteristic in a weak inverse state.
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Accused Products
Abstract
A welding condition monitoring device for monitoring the welding state of a welding work portion by taking an image thereof by an image sensor having a wide dynamic range and capable of taking an image covering a very bright welding portion and relatively dark portion. The monitoring device selectively emphasizes the outputs of the image sensor for any of luminance areas of the image taken by the image sensor using a sensor output characteristic table and can provide an image clearly showing both the very bright welding portion and the dark bead portion with a sufficient contrast allowing an observer to reliably recognize the objects in the image.
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Citations
43 Claims
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1. A welding condition monitoring device for monitoring a welding state of a welding work portion by taking an image thereof by an image sensor, which device has a means for selectively emphasizing outputs of the image sensor for any of luminance areas of the image by using an output-characteristic conversion table for the image sensor, whereby outputs relating to a high luminance welding portion and outputs relating to a low luminance bead portion area are emphasized respectively to increase a contrast between the currently welding portion and the already formed bead portion in the image, and outputs relating to an area between the high luminance welding portion and the low luminance bead portion area is fixed to a constant level, and signals of other remaining areas are omitted by compression,
and wherein each of plural light sensor circuits composing the image sensor represents a unit pixel and has a logarithmic output characteristic, and each of the light sensor circuits composing the image sensor represents a unit pixel and comprises a MOS transistor capable of converting a current flowing in a photodiode into a voltage signal with a logarithmic output characteristic in a weak inverse state.
- 23. A method for monitoring a welding state of a welding work portion, comprising the steps of taking an image of the welding work portion by an image sensor, selectively emphasizing outputs of the image sensor for any of luminance areas of the image by using an output-characteristic conversion table for the image sensor, whereby outputs relating to a high luminance welding portion and outputs relating to a low luminance bead portion are emphasized, respectively, to increase a contrast between the currently welding portion and the already formed bead portion in the image, and fixing the outputs relating to an area between the high luminance welding portion and the low luminance bead portion area to a constant level.
Specification