---
title: "ClikaRT::processor::ImageProcessorConfig"
sidebar_label: "ImageProcessorConfig"
description: "Settable configuration for an ImageProcessor (convert-rgb → resize → center-crop → rescale → normalize → pad)."
---

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**Header:** `ClikaRT/processor/config.h`

Settable configuration for an [`ImageProcessor`](./ImageProcessor.md) (convert-rgb → resize → center-crop → rescale → normalize → pad). Default-constructed to the documented HuggingFace defaults (resize + rescale by 1/255 + normalize on; crop + pad off); tune with the fluent setters, or round-trip a `preprocessor_config.json` through [`from_json`](./ImageProcessorConfig.md#from_json) / [`to_json`](./ImageProcessorConfig.md#to_json). Move-only.

## Static member functions

### from\_json() {#from_json}

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`static` [`ImageProcessorConfig`](./ImageProcessorConfig.md) **`from_json`**(`std::string_view` `text`)

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Parse a config from `preprocessor_config.json` text (flat, or nesting an `"image_processor"` block). Malformed text raises [`ClikaRT::Error`](../Error.md).

The accepted schema is [ClikaRT](../../index.md)'s own canonical config: the HuggingFace preprocessing keys plus the [ClikaRT](../../index.md) extension keys ([`target_dtype`](./ImageProcessorConfig.md#target_dtype), [`resize_before_cast`](./ImageProcessorConfig.md#resize_before_cast)). Two semantics to be aware of when feeding it a HuggingFace-authored file:

- A missing key takes [ClikaRT](../../index.md)'s documented default (this class's default-constructed state), NOT the per-processor-class default the HuggingFace `image_processor_type` would imply. Fields a HuggingFace class hardcodes rather than serializes must be set explicitly.
- A key outside the accepted schema is ignored for the parse but logged as a warning naming it, so a mis-spelled or unsupported key is a visible diagnostic, never a silently different pipeline.
- A `size` / `crop_size` / `pad_size` value is one of: a bare integer (for `size`, the shortest edge, aspect preserved, the CLIP-style `"size": 224`; for `crop_size` / `pad_size`, a square), a `[height, width]` list (an exact target), `{height, width}`, `{shortest_edge}`, `{shortest_edge, longest_edge}`, or `{max_height, max_width}`. Any other value form (a one-element list, a string, an object with another key set) is refused with an error naming the supported forms, never read as "no size".

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Declared in `ClikaRT/processor/config.h`, line 80

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## Member functions

### ImageProcessorConfig() {#ImageProcessorConfig}

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**`ImageProcessorConfig`**()

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A default configuration, usable with no config file.

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Declared in `ClikaRT/processor/config.h`, line 50

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### ImageProcessorConfig(ImageProcessorConfig) {#ImageProcessorConfig-2}

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**`ImageProcessorConfig`**(`ImageProcessorConfig&&`) `noexcept`

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move-construct (the source becomes an empty shell)

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Declared in `ClikaRT/processor/config.h`, line 51

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### operator=(ImageProcessorConfig) {#operator-assign}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`operator=`**([`ImageProcessorConfig`](./ImageProcessorConfig.md)`&&`) `noexcept`

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move-assign (the source becomes an empty shell)

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Declared in `ClikaRT/processor/config.h`, line 52

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### ImageProcessorConfig(ImageProcessorConfig) {#ImageProcessorConfig-3}

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**`ImageProcessorConfig`**(`const ImageProcessorConfig&`)

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copy-construct: a DEEP copy (independent settings)

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Declared in `ClikaRT/processor/config.h`, line 53

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### operator=(ImageProcessorConfig) {#operator-assign-2}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`operator=`**(`const` [`ImageProcessorConfig`](./ImageProcessorConfig.md)`&`)

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copy-assign: a deep copy

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Declared in `ClikaRT/processor/config.h`, line 54

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### \~ImageProcessorConfig() {#ImageProcessorConfig-4}

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**`~ImageProcessorConfig`**()

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destructor

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Declared in `ClikaRT/processor/config.h`, line 55

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### to\_json() {#to_json}

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`std::string` **`to_json`**(`int` `indent` `=` `2`) `const`

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Serialize to `preprocessor_config.json` text (`indent < 0` = compact), [ClikaRT](../../index.md)'s canonical form, with every field (defaults included) materialized. Every field round-trips through [`from_json`](./ImageProcessorConfig.md#from_json). Infallible.

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Declared in `ClikaRT/processor/config.h`, line 86

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### resize\_shortest\_edge(int64\_t) {#resize_shortest_edge}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resize_shortest_edge`**(`std::int64_t` `edge`)

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Resize the shortest edge to `edge`, preserving aspect (turns resize on): the `{shortest_edge}` size form; a bare integer `size` in a config file means the same. The other edge is truncated, never rounded, so a 480×640 image at 224 becomes 224×298.

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Declared in `ClikaRT/processor/config.h`, line 94

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### resize\_shortest\_edge(int64\_t, int64\_t) {#resize_shortest_edge-2}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resize_shortest_edge`**(`std::int64_t` `edge`, `std::int64_t` `longest_cap`)

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Resize the shortest edge to `edge` and cap the longest at `longest_cap` (the DETR-style aspect-preserving fit, the `{shortest_edge, longest_edge}` size form; turns resize on). When the cap binds, the shortest edge is re-derived from it: a 1080×1920 image at 800/1333 becomes 750×1333.

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Declared in `ClikaRT/processor/config.h`, line 99

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### resize\_to() {#resize_to}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resize_to`**(`std::int64_t` `height`, `std::int64_t` `width`)

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Resize to an exact `height`×`width` (turns resize on): the `{height, width}` / `[height, width]` size forms.

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Declared in `ClikaRT/processor/config.h`, line 102

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### resize\_within() {#resize_within}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resize_within`**(`std::int64_t` `max_height`, `std::int64_t` `max_width`)

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Fit inside `max_height`×`max_width` preserving aspect, the `{max_height, max_width}` size form (turns resize on). Scales up as well as down: the more constrained side lands exactly on its bound, the other is truncated; a 300×400 image within 100×60 becomes 45×60.

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Declared in `ClikaRT/processor/config.h`, line 107

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### set\_do\_resize() {#set_do_resize}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_resize`**(`bool` `on`)

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resize step on/off (the `resize_*` setters turn it on)

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Declared in `ClikaRT/processor/config.h`, line 108

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### resample(ImageResample) {#resample}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resample`**([`ImageResample`](./index.md#ImageResample) `mode`)

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The resize resampling filter (PIL vocabulary). Default bicubic.

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Declared in `ClikaRT/processor/config.h`, line 110

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### resample(ImageResample, bool) {#resample-2}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`resample`**([`ImageResample`](./index.md#ImageResample) `mode`, `bool` `antialias`)

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Filter + antialias in one call (the resize quality pair): `mode` picks the filter, [`antialias`](./ImageProcessorConfig.md#antialias) the smoothing.

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Declared in `ClikaRT/processor/config.h`, line 113

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### set\_antialias() {#set_antialias}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_antialias`**(`bool` `on`)

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Antialiased resize on/off. Default ON, the PIL behavior every HuggingFace image processor exhibits; turn off only to trade fidelity for speed on large downscales.

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Declared in `ClikaRT/processor/config.h`, line 117

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### center\_crop\_to() {#center_crop_to}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`center_crop_to`**(`std::int64_t` `height`, `std::int64_t` `width`)

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Center-crop to `height`×`width` (turns crop on).

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Declared in `ClikaRT/processor/config.h`, line 119

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### set\_do\_center\_crop() {#set_do_center_crop}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_center_crop`**(`bool` `on`)

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center-crop step on/off ([`center_crop_to`](./ImageProcessorConfig.md#center_crop_to) turns it on)

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Declared in `ClikaRT/processor/config.h`, line 120

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### pad\_to() {#pad_to}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`pad_to`**(`std::int64_t` `height`, `std::int64_t` `width`)

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Pad (detection-style) bottom/right with zeros to `height`×`width` (turns pad on).

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Declared in `ClikaRT/processor/config.h`, line 123

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### set\_do\_pad() {#set_do_pad}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_pad`**(`bool` `on`)

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pad step on/off ([`pad_to`](./ImageProcessorConfig.md#pad_to) turns it on)

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Declared in `ClikaRT/processor/config.h`, line 124

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### rescale\_by() {#rescale_by}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`rescale_by`**(`double` `factor`)

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Scale pixel values by `factor` (e.g. 1/255). Turns rescale on.

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Declared in `ClikaRT/processor/config.h`, line 126

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### set\_do\_rescale() {#set_do_rescale}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_rescale`**(`bool` `on`)

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rescale step on/off ([`rescale_by`](./ImageProcessorConfig.md#rescale_by) turns it on)

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Declared in `ClikaRT/processor/config.h`, line 127

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### normalize() {#normalize}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`normalize`**([`ClikaRT::Span`](../Span.md)`<const float>` `mean`, [`ClikaRT::Span`](../Span.md)`<const float>` `std`)

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Per-channel normalization (subtract mean, divide by std). `mean`/`std` are length 1 or 3; turns normalize on. The spans are read during the call.

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Declared in `ClikaRT/processor/config.h`, line 130

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### set\_do\_normalize() {#set_do_normalize}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_normalize`**(`bool` `on`)

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normalize step on/off ([`normalize`](./ImageProcessorConfig.md#normalize) turns it on)

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Declared in `ClikaRT/processor/config.h`, line 131

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### set\_do\_convert\_rgb() {#set_do_convert_rgb}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_do_convert_rgb`**(`bool` `on`)

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force 1/4-channel input to RGB before the pipeline (default on)

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Declared in `ClikaRT/processor/config.h`, line 132

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### set\_target\_dtype() {#set_target_dtype}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_target_dtype`**([`DataType`](../../index.md#DataType) `dtype`)

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The dtype the pipeline produces (and works in for rescale/normalize). The loaded image is cast to it exactly once, or not at all when it already matches. Default Float32.

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Declared in `ClikaRT/processor/config.h`, line 136

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### set\_resize\_before\_cast() {#set_resize_before_cast}

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[`ImageProcessorConfig`](./ImageProcessorConfig.md)`&` **`set_resize_before_cast`**(`bool` `on`)

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Resize/crop in the LOADED dtype and cast to [`target_dtype`](./ImageProcessorConfig.md#target_dtype) afterward, the HuggingFace/PIL order (default true). Set false to cast to [`target_dtype`](./ImageProcessorConfig.md#target_dtype) FIRST and resize in that dtype: the portable path for a device whose resize kernel does not cover the loaded integer dtype.

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Declared in `ClikaRT/processor/config.h`, line 141

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### do\_resize() {#do_resize}

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`bool` **`do_resize`**() `const`

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whether the resize step runs (default on)

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Declared in `ClikaRT/processor/config.h`, line 144

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### resample() {#resample-3}

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[`ImageResample`](./index.md#ImageResample) **`resample`**() `const`

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The resampling filter. A config whose PIL code has no filter here (e.g. LANCZOS) reads back `Bicubic`, the filter the pipeline actually runs.

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Declared in `ClikaRT/processor/config.h`, line 147

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### antialias() {#antialias}

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`bool` **`antialias`**() `const`

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whether resize antialiases (default on)

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Declared in `ClikaRT/processor/config.h`, line 148

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### do\_center\_crop() {#do_center_crop}

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`bool` **`do_center_crop`**() `const`

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whether center-crop runs (default off)

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Declared in `ClikaRT/processor/config.h`, line 149

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### do\_rescale() {#do_rescale}

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`bool` **`do_rescale`**() `const`

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whether rescale runs (default on)

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Declared in `ClikaRT/processor/config.h`, line 150

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### rescale\_factor() {#rescale_factor}

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`double` **`rescale_factor`**() `const`

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the rescale multiplier (default 1/255)

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Declared in `ClikaRT/processor/config.h`, line 151

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### do\_normalize() {#do_normalize}

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`bool` **`do_normalize`**() `const`

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whether normalize runs (default on)

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Declared in `ClikaRT/processor/config.h`, line 152

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### do\_convert\_rgb() {#do_convert_rgb}

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`bool` **`do_convert_rgb`**() `const`

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whether RGB conversion runs (default on)

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Declared in `ClikaRT/processor/config.h`, line 153

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### do\_pad() {#do_pad}

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`bool` **`do_pad`**() `const`

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whether detection-pad runs (default off)

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Declared in `ClikaRT/processor/config.h`, line 154

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### target\_dtype() {#target_dtype}

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[`DataType`](../../index.md#DataType) **`target_dtype`**() `const`

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the pipeline output/work dtype (default Float32)

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Declared in `ClikaRT/processor/config.h`, line 155

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### resize\_before\_cast() {#resize_before_cast}

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`bool` **`resize_before_cast`**() `const`

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whether geometry runs before the dtype cast (default true)

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Declared in `ClikaRT/processor/config.h`, line 156

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