Discharge determination method and discharge apparatus

Patent metadata

Field	Value
Publication number	US-10065208-B2
Application number	US-201615343911-A
Country	US
Kind code	B2
Filing date	Nov 4, 2016
Priority date	Nov 10, 2015
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

Whether or not a liquid is discharged from a nozzle is determined from an image. An index value larger in a discharge state than in a non-discharge state is calculated from an evaluation area including a path of the liquid. The discharge state or the non-discharge state is determined according to a relationship between the index value and a reference value. The reference value is determined according to a histogram of index values obtained from a plurality of images collected in advance. When an evaluation value indicating a peak position or the sharpness of a peak is smaller than a predetermined threshold value in the histogram, the collected images are assumed to show the non-discharge state. When the evaluation value is larger than the threshold value, the collected images are assumed to show the discharge state. Thus, the reference value is set for the discharge state and the non-discharge state.

First claim

What is claimed is:

1. A discharge determination method for determining whether a discharge state where liquid is discharged from a nozzle or a non-discharge state where the liquid is not discharged from the nozzle is set, the discharge determination method comprising:
performing imaging to obtain an image of an imaging field of view, wherein said discharged liquid flows down a flow-down path, and at least a part of said flow-down path is included in said imaging field of view;
obtaining an index value which is larger in the discharge state than in the non-discharge state based on pixel values of pixels in an evaluation area including at least a part of said image; and
determining that the image indicates the discharge state if the index value is larger than a reference value which is determined in advance while determining that the image indicates the non-discharge state if the index value is smaller than the reference value, the reference value being determined based on a histogram indicated by the index values obtained for the evaluation area of each of a plurality of images including the evaluation areas imaged at mutually different times,
wherein when the histogram exhibits unimodality:
if an evaluation value indicated by either the index value corresponding to the position of a peak or a value indicating the sharpness of the peak is smaller than a threshold value determined in advance, a value corresponding to a substantially maximum value of the index values in the histogram is set as the reference value; and
if the evaluation value is larger than the threshold value, a value corresponding to a substantially minimum value of the index values in the histogram is set as the reference value; and
wherein when the histogram exhibits bimodality, the index value corresponding to a valley between two peaks is set as the reference value.

2. The discharge determination method according to claim 1 , wherein the index value having a maximum degree of separation between classes is obtained by the discrimination analysis of two classes for a set of index values obtained for each of the plurality of images and whether or not the histogram is unimodal is judged based on a ratio of number of elements in a predetermined numerical range including the obtained value to the set.

3. The discharge determination method according to claim 2 , wherein the ratio is used as the evaluation value indicating the sharpness of the peak.

4. The discharge determination method according to claim 1 , wherein the index value is a value corresponding to a value of a population standard deviation when a set of total values which are obtained by individually totaling pixel values for each pixel column composed of pixels arranged along a liquid flowing direction in the evaluation area is a population.

5. The discharge determination method according to claim 1 , wherein the index value is a value corresponding to the number of pixels having pixel values corresponding to luminance higher than a predetermined luminance in the evaluation area.

6. A discharge determination method for determining whether a discharge state where liquid is discharged from a nozzle or a non-discharge state where the liquid is not discharged from the nozzle is set, the discharge determination method comprising:
performing imaging to obtain an image of an imaging field of view, wherein said discharged liquid flows down a flow-down path, and at least a part of said flow-down path is included in said imaging field of view;
obtaining an index value which is larger in the discharge state than in the non-discharge state based on pixel values of pixels in an evaluation area including at least a part of said image; and
determining that the image indicates the discharge state if the index value is larger than a reference value which is determined in advance while determining that the image indicates the non-discharge state if the index value is smaller than the reference value, the reference value being determined based on a histogram indicated by the index values obtained for the evaluation area of each of a plurality of images including the evaluation areas imaged at mutually different times in the non-discharge state,
wherein the reference value is a value corresponding to a substantially maximum value of the index values in the histogram.

7. A discharge determination method for determining whether a discharge state where liquid is discharged from a nozzle or a non-discharge state where the liquid is not discharged from the nozzle is set, the discharge determination method comprising:
performing imaging to obtain an image of an imaging field of view, wherein said discharged liquid flows down a flow-down path, and at least a part of said flow-down path is included in said imaging field of view;
obtaining an index value which is larger in the discharge state than in the non-discharge state based on pixel values of pixels in an evaluation area including at least a part of said image; and
determining that the image indicates the discharge state if the index value is larger than a reference value which is determined in advance while determining that the image indicates the non-discharge state if the index value is smaller than the reference value, the reference value being determined based on a histogram indicated by the index values obtained for the evaluation area of each of a plurality of images including the evaluation areas imaged at mutually different times in the discharge state,
wherein the reference value is a value corresponding to a substantially minimum value of the index values in the histogram.

Assignees

• Screen Holdings Co Ltd

Inventors

• Okita Yuji

Classifications

• H10P72/0604

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P72/0414 Primary

  using mainly spraying means, e.g. nozzles · CPC title

• B05C1/00

  Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating (B05C5/02, B05C7/00 take precedence) · CPC title

• B05D1/02 Primary

  performed by spraying · CPC title

• G06T2207/10024

  Color image · CPC title