Angular UI Grid - Filter on display values within registerRowsProcessor

We have a requirement to filter the contents of a grid using values/inputs that are not embedded into the UI Grid Column headers. The filtering must occur on the values that are displayed or in other word have been "filtered" for presentment. I have been able to successfully filter on values that don't have a cellFilter specified by specifying a filter method using the registerRowsProcessor.

$scope.externalFilterImpl = ( renderableRows ) => {
    if($scope.externalFilterValues.name.length>0)
    {
        // Case insensitive matching
        var matcher = new RegExp($scope.externalFilterValues.name, "i");
        renderableRows.forEach( function( row ) {
            var match = false;
            debugger;
            if ( row.entity["id"].match(matcher) ){
            //var value = $scope.gridApi.grid.getCellDisplayValue(row, "id");
            //if ( value.match(matcher) ){
                match = true;
            }
            if ( !match ){
                row.visible = false;
            }
        });
    }


    return renderableRows;
};

The code expects to filter on the display value (filtered value) for the column with the columnDef field property of "id". The columnDef for "id" appears as follows:

        {
            field: "id",
            cellClass: "cellContent",
            displayName: $translate.instant('tableHeading.item'),
            enableColumnMenu: false,
            enableHiding: false,
            suppressRemoveSort: true,
            filter: {
                placeholder: "Enter a name search"
            },      
            cellFilter: 'translateIds:"itemIds"', 
            filterCellFiltered:true, 
            sortCellFiltered:true,                           
            sort: {
                direction: uiGridConstants.ASC,
                priority: 0,
            },                
            cellTemplate: `<div class="ui-grid-cell-contents">
                        {{COL_FIELD CUSTOM_FILTERS}}
                    </div>`
        }

Any assistance would be greatly appreciated.