In order to run searches and highlight the document preview image in Logikcull, the document must have at least one of these two properties:
Document has been ingested with a searchable text layer on the preview image, OR
OCR was run on a document image, adding the text layer during processing.
If you are looking for terms to be highlighted on the image of the document, one of these two factors would have to be true:
The document was ingested with an existing searchable text layer already on the image of the document.
Logikcull OCRed the document (either because the document did not meet the minimum threshold of text, or the document was force OCRed by customer request).
Learn more about OCR and native text layers in this article.