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https://issues.apache.org/jira/browse/NIFI-1815?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15308459#comment-15308459
]
ASF GitHub Bot commented on NIFI-1815:
--------------------------------------
Github user rkarthik29 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/397#discussion_r65249839
--- Diff:
nifi-nar-bundles/nifi-ocr-bundle/nifi-ocr-processors/src/main/java/org/apache/nifi/processors/ocr/TesseractOCRProcessor.java
---
@@ -0,0 +1,359 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.nifi.processors.ocr;
+
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.FileFilter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import javax.imageio.ImageIO;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.AllowableValue;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.io.StreamCallback;
+import org.apache.nifi.processor.util.StandardValidators;
+
+import net.sourceforge.tess4j.ITesseract;
+import net.sourceforge.tess4j.Tesseract;
+import net.sourceforge.tess4j.TesseractException;
+
+@Tags({"ocr", "tesseract", "image", "text"})
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@CapabilityDescription("Extracts text from images using Optical Character
Recognition (OCR). The images are pulled from the incoming" +
+ " Flowfile's content. Supported image types are TIFF, JPEG, GIF,
PNG, BMP, and PDF. Any Flowfile that doesn't contain" +
+ " a supported image type in its content body will be routed to the
'unsupported image format' relationship and no OCR will be performed." +
+ " This processor uses Tesseract to perform its duties and part of
that requires that a valid Tesseract data (Tessdata) directory" +
+ " be specified in the 'Tessdata Directory' Property. This
processor considers a valid Tessdata directory to be an existing directory on
the" +
+ " local NiFi instance that contains one or more files ending with
the '.traineddata' extension. The list of supported languages" +
+ " is built from the Tessdata directory configured by listing all
files ending with '.traineddata' and considering those" +
+ " Tesseract language models. You can create you own Tesseract
language models and place them in your Tessedata directory" +
+ " and the processor will display it in the dropdown list of
languages available. All valid Tesseract configuration values" +
+ " may be passed to this processor by use of the 'Tesseract
configuration values' which accepts a comma separated list" +
+ " of key=value pairs representing Tesseract configurations.
'Tesseract configuration values' is where all of your tuning" +
+ " values can be passed in to help increase the accuracy of your
OCR operations based on your expected input images." +
+ " TesseractOCRProcessor only supports installations of Tesseract
version 3.0 and greater.")
+public class TesseractOCRProcessor extends AbstractProcessor {
+
+ public static Set<String> SUPPORTED_LANGUAGES;
+ private static final String TESS_LANG_EXTENSION = ".traineddata";
+ private static List<AllowableValue> PAGE_SEGMENTATION_MODES;
+ private static volatile ITesseract tesseract;
--- End diff --
I think these values must be available to be set by the user when they
configure the processor, and since all the propertydescriptor are declared
static, i think these have to be declared static as well.
```
public static final PropertyDescriptor TESSERACT_PAGE_SEG_MODE = new
PropertyDescriptor
.Builder().name("Tesseract Page Segmentation Mode")
.description("Set Tesseract to only run a subset of layout
analysis and assume a certain form of image.")
.required(true)
.defaultValue(PAGE_SEGMENTATION_MODES.get(3).getValue())
.allowableValues(PAGE_SEGMENTATION_MODES)
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.build();
```
Having said that, do you think it is correct to make propertydescriptor
static, as a particular property for a process could be different for each
flow. Changing the property of a processor in one flow affect a processor (same
processor, different instance) in another flow.
> Tesseract OCR Processor
> -----------------------
>
> Key: NIFI-1815
> URL: https://issues.apache.org/jira/browse/NIFI-1815
> Project: Apache NiFi
> Issue Type: Improvement
> Reporter: Jeremy Dyer
> Assignee: Jeremy Dyer
> Attachments: 0006-changes-to-the-OCR-processor.patch,
> nifi_1815_1.x_patch.zip
>
>
> This ticket is a follow-up to NIFI-1718 minus the use of the Tika library
> Expose OCR capabilities through a new processor which uses the Tesseract
> library. Use of this processor would require that Tesseract be installed on
> the NiFi host. Since the processor will have a system dependency care must be
> taken to ensure that the overall NiFi cluster continues to function properly
> in the absence of the Tesseract system dependency even though the OCR
> processor itself will be unable to perform its duties. In the event that the
> system dependencies are not detected the processor should display a
> validation warning rather than failing or preventing the NiFi instance from
> booting properly.
> Properties expose to configure Tesseract
> tesseractPath - Path to tesseract installation folder, if not on system path.
> language - Language ID (e.g. "eng"); language dictionary to be used.
> pageSegMode - Tesseract page segmentation mode, defaults to 1.
> minFileSizeToOcr - Minimum file size to submit file to OCR, defaults to 0.
> maxFileSizeToOcr - Maximum file size to submit file to OCR, defaults to
> Integer.MAX_VALUE.
> timeout - Maximum time (in seconds) to wait for the OCR process termination;
> defaults to 120.
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